Home

ODEON Room Acoustics Program

1. Ready Sum 825 WY Figur D1 Copying a material from MsExcel A material to be copied may contain a leading comment name and must end by 24 floating point values denoting the 24 reduction indexes from 50 Hz to 10000 Hz the first value is always assumed to be for the 50 Hertz one third octave band if the number of bands is less than 24 then the last value is used for the bands above if more than 24 values the values above 10 kHz are discarded To copy the values from MsExcel mark the relevant cells and press Ctrl C to paste the values into Transmission dialog simply press Ctrl V Likewise to copy data from the Transmission dialog to MsExcel press Ctrl C while the dialog is the selected window in Odeon then select the first cell in MsExcel or which ever cell is relevant and press Ctrl V Data can also be imported from Insul Sound Insulation Prediction software 50 simply by Copy the spectrum for Bastian format and paste into ODEON Single or double sided walls Sometimes a transmission wall may be composed by two individual surfaces two separate surfaces in the MaterialsList as shown in the illustration from the 3DBilliard display below It is possible for Odeon to link together such a pair of surfaces if they are almost parallel allowing transmission trough walls with a thickness and with different absorption properties on either side To accomplish this it is important that e Transmission type is assigned to both surfac
2. 4 64 64 78 2 68 51 52 49 62 2 02 48 22 1 1 45 3 2 68 43 85 1 45 42 40 40 98 1 45 0 000 ElevSurf2 1 122 2 7 TB walls HHT Defining a number of surfaces using the CountSurf statement The CountSurf is mostly here for backwards compatibility In most cases it will be easier to use the Surf statement along with a for end loop A Counter surface is divided on two lines and must follow the syntax CountSurf lt First Surface Number gt lt NumberOfSurfaces gt lt Optional name gt lt ListOfPointNumbers gt lt FirstSurfaceNumber gt A unique number from 1 to 2 147 483647 for identification of the surface Using the same number but with negative sign defines the surface and its mirrored counterpart in the XZ pane Y 0 A CountSurf will take up several surfaces numbers which must all be unique lt NumberOfSurfaces gt The number of surfaces to be created by the CountSurf call lt Optional name gt Optional user defined name for easy identification of the surface e g Beam lt ListOfPointNumbers gt Each surface may be bounded by between 3 and 50 corners which all lie in a plane Corner numbers refer to the corners which must have been defined e g using the Pt or CountPt statement before using the surface statement The order of listing must be as obtained by travelling around the surface s edge in either direction The list of corners must be on the same line A room
3. 5 decay curve Dso Deutlichkeit definition early O 50 ms to total 5 energy ratio Cso dB Clarity early O 80 ms to late 80 energy ratio 1 dB Ts ms Centre time time of first moment of impulse response 10 ms or gravity time G dB Sound level related to omni directional free field 1 dB radiation at 10 m distance LF Early lateral 5 80 ms energy ratio cos lateral 5 angle STI RASTI Speech Transmission Index 0 05 Room acoustical parameters and their subjective limen as given by Bork 39 and Bradley 40 Example 1 If the real G value is 1 dB and the simulated is 1 9 dB then the difference is not noticeable Example 2 If the real LF value is 12 and the simulated is 17 the difference is just noticeable Note When comparing measured parameters to the ones simulated it should be kept in mind that the measured parameters are not necessarily the true ones as there are also uncertainties on the measured results as well These errors are due to limited tolerances in the measuring equipment as well a limited precision in the algorithms used for deriving the parameters from the measured impulse response or similar errors if results are not based on an impulse response measuring method There may also be errors due to unprecise source and receiver positions 9 1 Sources of error There are many sources of errors in a room acoustical simulation leading to results which are less than p
4. Vol 80 No 3 pp 837 845 1986 41 The CIPIC HRTF Database hitp interface cipic ucdavis edu 42 Linda Parati Filipe Ortondo Comparison of Directional Sources in Simulating a Soprano Voice Procedings of the Stockholm Music Acoustics Conference August 6 9 2003 SMAC 03 Stockholm Sweden 100 43 M A Gerzon General Metatheory of Auditory Localisation Preprint 3306 of the 92 Audio Engineering Society Convention Vienna March 1992 44 Bamford Jefery Stephen An Analysis of AmbisonicsSound Systems of First and Second Order A thesis presented to the University of Waterloo in fulfilment of the thesis requierement for the degree of Master of Science in Physics Waterloo Ontario Canada 1995 http audiolab uwaterloo ca jeffb thesis thesis html 45 Dave Malham Home page for Ambisonics and related 3 D audio research Music Technology Group The University of York http www york ac uk inst mustech 3d_audio 46 Richard Furse 3D Audio Links and Information http www muse demon co uk 3daudio html 47 Ingolf Bork Report on the 3 Round Robin on Room Acoustical Computer Simulation Part II Calculations Acta Acoustica United with Acoustica Vol 91 2005 p 753 763 48 M R Schroeder Digital Simulation of Sound Transmission in Reverberant Spaces JASA 47 424 431 1970 49 DIRAC http www acoustics engineering com dirac dirac htm 50 Insul Marshall Day Acoustics http ww
5. e the room contains de coupling effects e g connected corridors or niches Thus the results given by Quick Estimate should not be considered to be a final result Even so the method is useful in the initial work on assigning reasonable materials to the surfaces in the room Global estimate is a more precise method which doesn t make any assumptions about diffuse field conditions and as such it is a more reliable method for estimation of global reverberation time e For workrooms where all absorption is often situated in the ceiling region and sources are situated in the floor region the RT predicted by Global Estimate will typically be longer than the values predicted by Quick Estimate a factor two is not unlikely if walls are basically smooth e In auditoriums the opposite is the case because the dominant absorption area the audience is close to the source In any case the RT s predicted by Global Estimate is the most reliable provided that proper scattering coefficients have been entered The principle of the method was first suggested by Schroeder 48 DERRE i Point Response calculations The Point response calculations estimate not only RT but also room acoustic parameters like Clarity Deutlichkeit SPL SPLa STI and LFso see chapter 7 The calculated results can be thought of as a simulated measurement Calculated results relates to e a number of active sources e one receiver position e orientation of the receive
6. Speech Transmission Index known as STI is calculated according to 7 The STI parameter takes into account the background noise which may be adjusted from the Room Setup For the STI parameter to be valid it is very important to adjust the background noise accordingly remember that background noise must be set in a relative level if relative source gains are used It should be mentioned that it is not stated in 7 what kind of directivity the source in the STI measuring system should have so if using a source with directivity different from the one used in the real measurements in the simulations results may not be comparable The subjective scale of STI is given below Subjective scale STI value Bad 0 00 0 30 Poor 0 30 0 45 Fair 0 45 0 60 Good 0 60 0 75 Excellent 0 75 1 00 DL Rate of Spatial Decay Rate of spatial decay is the decay of sound pressure level per distance doubling DL2 is calculated according to ISO 14257 2 The DL2 parameter is intended to characterise the acoustic performance of workrooms The values to be expected for the DL2 parameter is according to 1 1 3 dB for reverberant rooms and 2 5 dB for ideally treated rooms The design criterion for DL2 is set to 3 5 dB or better according to ISO 11690 1 3 The DL2 parameter is calculated as a part of the Multi Point response if the job only contains one active source the active source is a point source more than one receiver
7. To reset cancel the most resent manipulation MTranslate in the example above use the MPop command which will pop the operation of the matrix stack Hints The order in which the coordinate manipulations are carried out is important usually but not necessarily always the MScale commands should come first then the MRotate commands and finally the MTranslate commands 3 34 If you are not familiar with coordinate manipulations it may be a good exercise to try different manipulations on the sample geometry above and load the geometry into ODEON upon each change Using layers in ODEON The Layer statement allows dividing a geometry into separate parts which can be displayed separately and in its own layer colour in the 3DView 3DOpenGL and Materials list This makes it easier to model and investigate selected groups of surfaces When importing geometry from a DXF file e g from AutoCAD where layers are an integrated part the layers included in that file will be preserved in the imported version of the room If layers have been used in a geometry the layer can be activated or deactivated in the 3DView 3DOpenGL and Materials list The layers menu is activated from these windows using the Ctrl L shortcut Vocabulary what s a layer Layers are commonly used in CAD modeling programs such as AutoCAD in order to make complicated geometries manageable Layers in CAD programs and some drawing and picture editing programs can be
8. absorption material e g Odeon material 901 902 903 or 904 c Assign a high scattering coefficient of 0 7 to this area d Place the receivers some 1 2 metres above the floor Audience B Modeling the audience as boxes Model the audience area as audience boxes with a height of approximately 0 8 metres above the audience floor b Assign appropriate absorption material e g Odeon material 901 902 903 or 904 c Assign a high scattering coefficient of 0 7 to the surfaces of the audience box d Position the receivers some 0 4 metres above the modeled audience box Experiences from tests with first approach are positive and it is far the easiest to model The Elmia hall is an example of this A potential drawback of modeling the audience area as a box is that it removes volume from the room which is may be a problem in rooms with low ceiling height volume 3 20 How to model the podium on stage Same guideline as for the audience area goes here Rather than modeling each step of the podium on stage the podium can be simplified into a few sloped surfaces Should fumiture such as tables chairs and shelves be included in a model of an office If a table plate is close to a source or receiver point then it is likely to produce a strong specular reflection at the receiver so if this is the case then it should be included Furniture such as shelves and screens in large office environments which subdivi
9. clicking the Play Single Point BRIR button The BRIR may give a first clue as to how the room sounds and it also allows some evaluation of the quality of the calculated point response e g whether to use a higher number of rays or a higher Reflection density in the Room setup Although the BRIR may sound a little rough it may work quite realistic when convolved with a signal less transient than an ideal Dirac function To get a more realistic presentation of a BRIR as it would sound in the real world you might want to convolve it with the Clapping signal file an anechoic recording of hands being clapped which is eventually a less transient signal than an ideal impulse A note on directivity patterns for natural point sources With natural sources we refer to sources such as human voice an acoustical instrument or similar where a recorded signal for auralization may be associated with the directivity pattern Directivity patterns for natural sources may be used for auralization of the very same signal it represents and if not handled correctly this will result in auralization where the overall frequency response is included not once but twice first time through the directivity pattern which includes the overall frequency response second time through the source signal which inherently also include that response For calculation of acoustical parameters it is desirable that the true frequency contents is included in the directivity pattern e
10. compared to overhead sheets without any thickness You define a number of layers with different names and possibly different line colour thickness etc and draw the different parts of your geometry on the different layers The layers can be turned on or off in the CAD program allowing better overview by hiding parts of the geometry that are not relevant in a part of the drawing process Syntax for the Layer statement Layer lt Layer name in quotes gt lt R intensity gt lt G intensity gt lt B intensity gt or as another option Layer lt Layer name in quotes gt lt LayerColour gt lt Layer name in quotes gt A descriptional name which must start and end with a quote sign lt R intensity gt lt G intensity gt lt B intensity gt Three floating point values between O and 1 which together is describing the colour of the layer as a Red Green Blue intensity If using the Layer command Shift Ctrl L from within the Odeon editor the colour intensities are set by clicking the desired colour in a dialog box Do note that its not advisable to choose a greyish colour as may not be visible in ODEON lt LayerColour gt As another option the colour of the layer can be described using one of the predefined colours Black Blue Cream Fuchsia Gray Green Lime Maroon Navy Olive Purple SkyBlue Teal or White The LayerColours par example demonstrates the different colours The LayerStatement par example shows how to create a
11. effect on the estimated reverberation time unless strong decoupling effects are present in the room ES Room setup calculation parameters At this point you should have an idea of the order of size of the reverberation time To continue the series of calculations you should enter the Room setup and specify the Impulse response length The Impulse response length should cover at least 2 3 of the reverberation curve in this case 2000 ms should be sufficient To learn more about the other parameters available from this page please press F1 Global Estimate a reliable method for estimation of reverberation time Run Global Estimate and let it run until you are satisfied that the decay curve has become stable and then press the Derive results button Note the longest reverberation time The reverberation time differs from the values calculated by Quick Estimate because the room shape and the position of absorbing material are taken into account It is important that the Impulse response length in the Room Setup is at least 2 3 of the reverberation time 2 6 J Calculating point responses At this point we are ready to calculate point responses Three different point response calculations are available e Single Point response offering detailed calculation results and auralization options for a selected receiver e Multi Point response offering room acoustical parameters for all the receivers defined in the Receiver list at the Source rece
12. rays sent from a point source is handled a little different in order to combine with the hybrid calculation method rays are reflected specular as long as the reflection order is less or equal to the Transition order specified at the Room Setup dialog this is done in order to allow the detection of image sources up to the specified order above this order the rays are reflected using the Late ray reflection method Vector Based Scattering reflecting a Late ray Vector based scattering is an efficient way to include scattering in a ray tracing algorithm The direction of a reflected ray is calculated by adding the specular vector Snell s law scaled by a factor 1 s to a scattered vector random direction following the angular Lambert distribution of ideal scattered reflections sin20 2 which has been scaled by a factors where Sis the scattering coefficient If sr is zero the ray is reflected in the specular direction if it equals 1 then the ray is reflected in a random direction Often the resulting scatter coefficient may be in the range of say 5 to 20 and in this case rays will be reflected in directions which differ just slightly from the specular one but this is enough to avoid artifacts due to simple geometrical reflection pattern i Incident i lt Specular weight 1 s A L Resulting X Scattered weight s Figur 3 Vector based scattering Reflecting a ray from a surface with a scattering coefficient o
13. the difference being greater flexibility more channels allowed individual adjustment of each channel is allowed plus auralization results are stored in wave files which may be used on the WEB CD ROM s Power Point presentations etc Click the Toggle button to get to the auralization display This display is divided into a left and a right part In the left display mono signals are convolved with Binaural Room Impulse Responses BRIR s which have been calculated as part of the Single Point responses this process may be compared to a binaural recording of a mono signal played through simulated source s in the room The right part of the auralization display two tables is a mixer allowing convolved results to be combined into one wave file allowing multi channel simulations e g stereo setups singer versus orchestra etc The Offline auralization offers greater flexibility than the real time auralization allowing full control over which signal to pass through which of the 300 channels available and assigning individual level and delay to each channel If for some reason you need the auralization output as a wave file it is also the offline auralization which should be used 2 9 Single channel simulation First try to create a one channel simulation of a person speaking from source position 1 In the auralization display select the Conv no 1 row and select the Voice Sabine Short file in the signal file field this is an anechoic recordin
14. 0 1 0 in the geometry file using the point 2 in a surface definition of the geometry file will refer to the auto generated point Pt 2 1 0 1 0 1 0 Thus the following surface definition Surf 1000 Symmetric surface 1 2 2 1 will model a surface symmetric around the XZ plane Y 0 e g an end wall or a reflector If the surface is completely symmetric as above then the symmetric points can also be specified using the Mirror word which should be the last component in the corner list Surf 1000 Symmetric surface 1 2 Mirror Note You should not try to define the point 2 in the geometry file it is automatically generated Symmetric double surface Symmetric double surfaces are pairs of surfaces symmetric around the XZ plane Y O e g a right and a left wall Surf 2 Right wall Left wall 12 22 23 13 will appear as two surfaces inside the ODEON program Thus you will have the following two surfaces inside the ODEON program 3 36 2 Right Left wall containing the symmetric points 12 22 23 13 and the surface 2 Right Left wall containing the points 12 22 23 13 as they are defined in the geometry file Note You may not define surface 2 if you are using the symmetric double surface 2 because ODEON automatically generates surface number 2 The Box statement The Box statement defines a Box with or without top and bottom The Box statement may typically be used for Box shaped rooms and columns A specia
15. 16 const R 15 const H 10 Cone 1 N R 270 H Cone shaped ceiling HH Hint The cone can be made elliptical using the MScale statement The Dome statement The Dome statement generates a full dome half hemisphere covering the full 90 vertical angle In most cases the Dome2 statement is probably better suited The syntax for Dome is Dome lt Number gt lt NumberOfSurfaces gt lt Radius gt lt RevAngle gt lt optional name gt lt Number gt A unique number from 1 to 2 147 483647 for identification of the first point and surface in the Dome Using the same number but with negative sign defines the dome and its mirrored counterpart in the XZ plane Y 0 Dome will take up several point and surface numbers which must all be unique lt Radius gt Radius of the Dome must always be greater than zero lt Revangle gt Revangle must be within the range 360 and different from zero If RevAngle is 180 a half Dome is generated if its 360 a full Dome is generated Positive revolution angles are defined counter clockwise Connection points The right side vertical points in Dome are stored in PlistA The left side vertical points in Dome are stored in PlistB In the special case where the revolution angle is 180 all points are stored in Plistd and the number of vertical subdivisions is stored in ONVert The example shown was generated with the following code HHH const N 16 const R 15 Dome 1 NR
16. 270 This is a dome HHH Hint The dome can be made elliptical using the MScale statement 3 40 The Dome2 statement te The Dome2 statement is a Dome shell of the calotte type where the LFF SSS 7 ESS vertical revolution angle is not necessary 90 Rather then specifying 4A SS SN the dome by a revolution angle it is specified by the width and height Dome2 may typically be used for modeling dome shaped ceilings The syntax for Dome is Dome2 lt Number gt lt NumberOfSurfaces gt lt Width gt lt Height gt lt RevAngle gt lt optional name gt lt Number gt A unique number from 1 to 2 147 483647 for identification of the first point and surface in the Cone Using the same number but with negative sign defines the surface and its mirrored counterpart in the XZ pane Y O A Cone will take up several point and surface numbers which must all be unique lt NumberOfSurface gt Specifies the number of surfaces in one horizontal ring of the dome around 16 to 24 surfaces per ring is suggested ODEON will automatically calculate the number of subdivisions in the vertical level If the revolution angle is 180 the number is stored in the ONVert variable would have been 9 in the example above The ONVert variable may help when connecting a Dome2 to a Cylinder2 in order to specify the correct number of surfaces in the cylinder lt Width gt Width at the beginning of the dome The width must always be greater than zero lt Rev
17. Add a material allow to create new materials or to edit existing ones The material editor available assists in mixing different materials into one 4 60 Surface List Material List window The surface list lists the material specifications assigned to the surfaces starting from the left to the right Surface number The unique number assigned to the surface in the geometry file Material number The number of the material assigned to the surface from the material library This number and material correspond to the number listed in the material display except when e The material has been edited in the material library after the material was assigned to the surface e g its absorption coefficients have been changed e The materials were assigned on another computer where another material library was available with different definitions of the material having this number Note Once a surface has been assigned a material this material sticks to the surface even though the material has been changed in the material library Material Li8 thus calculated results stays in consistency with the materials assigned to the room To make such a new material take effect in the room please reassign the material e g using the Global Replacement option Another option is to change the absorption coefficients of room material using the edit fields below the surface list in the left side of the materials list doing so will change the absorption o
18. Finally move the chair to the desired location using the left mouse button Using the circle tool and the mirror 14 00 Io 00 hoo too Io 00 hoo o0 ood ooo ae 000 000 ooo EET EE 0 00 000 ag at 1 00 1 00 _ q 10 1 00 1 00 i x 200 2 00 2 00 2 00 2 00 Z Z Z opi l j 1 00 o jo o jao 4b 1 00 In this example a table plate with circular ends is modeled a First a circle is created b Then half of the circle is deleted c Finally the surfaces is mirrored in a horizontal mirror at y 1 Creating a circular surface To create a circular surface first draw a line a surface with two points in order to specify centre and radius or the circle then use the Ctrl O shortcut to activate the circle tool and accept to create a circle from 12 points If the circle tool is clicked when the selected surface contains less than two or more than three points then a help text is displayed this text will also explain about ellipses Make a circle half a circle Delete the 5 upper points in the circle in order to reduce the circle to half a circle At this point you should have created the half circle in middle of figure above Mirroring the surface In order to create the complete table the mirror functionality can be used select the horizontal mirror and specify the coordinate of the mirror line in the figures the coordinate was 1 00 Select the first 3 51 of the two points to be connected across the mir
19. Less common operations are available from the dropdown menu in the top of the Odeon program window menus will change in order to facilitate the currently selected window or indeed the selected tabsheet in the currently selected window If looking for a facility in a window it is quite likely that it can be found in the dropdown menu Context sensitive help Context sensitive help is available using the F7 shortcut key throughout the program The help includes description of the facilities available in a particular window suggestions on the choice of calculation parameters hints on the evaluation of calculation results etc Answers to questions which go on a Specific window are found in the context sensitive help rather than in this paper manual Saving data and maintaining consistent results The ODEON program automatically saves the user entered data such as sources and materials with the room Whenever data need to be defined in order to carry out calculations ODEON will prompt whether to accept or discard changes If the changes are accepted ODEON will automatically erase results that are no longer valid ensuring that results are always consistent with data entered When you close a window data is automatically saved your upon acceptance so as a general rule there are no Save buttons available in ODEON dialogs 2 1 Short guided tour Combined and Auditorium editions Si Run the ODEON application You will find the ODEON program a
20. N Window tube Surf 100 Window glass 200 gt 200 N 1 HE 3 47 3 3 Odeon Extrusion Modeler A small modeling program the Odeon Extrusion Modeler is included with Odeon The program is found in the Windows start menu along with the Odeon program It can also be launched from within the Odeon editor The Extrusion modeler allows modeling so called extruded geometries in a graphic environment or in other words to draw geometries using the mouse An extruded surface is a flat 2D outline drawn at a specified drawing depth the third coordinate and with an extrusion height When assigning an extrusion height to the 2D outline it becomes a holster outlined by the edges of the extrusion surface if so desired this holster can have a bottom and a top Odeon 1985 2004 In the extrusion modeler it is possible to make one drawing which contains multiple extrusion surfaces each described by a 2D outline a simple drawing and the line properties drawing depth extrusion height bottom flag top flag and a name If the extrusion is created in the XY plane then one extrusion surface may form walls floor and ceiling whereas other extrusion surfaces define tables chairs or screens Odeon 1985 2004 For some geometry it may be more appropriate to draw the geometries in one of the other main planes XZ and YZ planes As an example the auditorium par model in the figure has been modeled in the XZ plane using
21. Single Point Multi and Grid This display is a very valuable tool for debugging of new models e g to detect missing or misplaced surfaces It may also give an impression of what is happening in the calculations e g the effect of the scattering assigned to the surfaces Click the Ok button then click the Single forward button a few times and note the behaviour of the ray tracing 3D Billiard The 3D billiard display is a tool that can be used for investigating or demonstrating effects such as scattering flutter echoes or coupling effects A number of billiard balls are emitted from the source and reflected by the surfaces in the room To speed up the process set the Dist per update to a higher value To visualize a flutter echo a large Number of billiard balls should be used e g 10000 balls It s easier to visualize a flutter echo if rays are only emitted in the relevant plane XZ YZ or XY If the geometry is complicated it may be hard to see the billiard balls in that case toggle parts of the geometry off using the T shortcut 2 3 Pre calculated Rooms Round Robins At this point you have tried the basic functions in ODEON and may want the view results for more realistic rooms In the room directory you will find pre calculated results in the rooms Elmia RoundRobin2 detailed par and PTB_Studio open curtains detailed model par which were the rooms used as test objects in the 2 39 and 3 47 International Round Robins on Room
22. a SO8 file can be used without further Gain or EQ settings in ODEON In certain cases the form of the available data or the mode of usage may make this approach inappropriate Sensitivity and EQ within DirectivityFileUtility exe and Gain and EQ within ODEON may be combined in many ways to achieve the desired result 10 95 Text format The data presented to the Odeon should be in relative calibration across frequency but need not be in any absolute calibration this calibration is applied from within the program Thus the data for the forward on axis direction constitutes a relative frequency response for that direction which is used to calculate the frequency dependency of the source s on axis sensitivity The first non comment line of the input file indicates whether the data is for e FULL set for complex sources where directivity data is known for each 10 Azimuth and 10 Elevation e SYMMETRIC set for symmetric sources e g a trumpet e POLAR set containing only horizontal and vertical polar plots for sources where only a horizontal and a vertical plot are known e g a loudspeaker Each of the subsequent lines of the input file should contain sound levels in dB for a complete 180 of elevation from the forward axis to the backward axis The resolution must be 10 hence each line contains 19 values 0 10 20 160 170 and 180 Comment lines are allowed anywhere in the ASCII input file s When only hor
23. about the uncertainty of material data if the room does not exist except taking the uncertainty of the materials into account in the design phase If the room does indeed exist and is being modeled in order to evaluate different possible changes it may be a good idea to tweak adjust such uncertain materials until the simulated room acoustical parameters fits the measured ones as good as possible Absorption properties in a material library are often by users assumed to be without errors This is far from being the truth For high absorption coefficients and high frequencies the values a probably quite reliable however low frequency absorption data and absorption data for hard materials will often have a lack of precision Low frequency absorption At low frequencies the absorption coefficients measured in a reverberation chamber are with limited precision because e There are very few modes available in a reverberation chamber at lowest frequency bands e Low frequency absorption occurs partly due to the construction itself rather than its visible surface structure Often it may not be possible to reconstruct a complete building construction is a reverberation chamber and if reconstructing only a fraction of the wall in the reverberation chamber it will have different absorption properties because it becomes less or more stiff There is no current solution to these problem but one can hope that new measuring techniques will to some extend overc
24. are assigned to transmission walls when transmission walls are composed from a single surface two surfaces and three surfaces Once the room has been loaded into Odeon additional information is available in the Notes editor using the Shift Ctrl N shortcut In the Joblist some example setups have been prepared for calculations in source as well as in receiver rooms 105
25. are stored in PlistA The top points in Cylinder2 are stored in PListB The example shown was generated with the following code HHH Const N 10 Const W 5 Const H 1 Const L 10 Cylinder2 1 N W H L TB Cylinder calotte HE Hint The cylinder can be made elliptical using the MScale statement The Cone statement The Cone statement models a cone Typical use of the Cone statement is for modeling half cone or cone shaped ceilings The syntax for Cone is Cone lt Number gt lt NumberOfSurfaces gt lt Radius gt lt RevAngle gt lt Height gt lt optional name gt lt Number gt A unique number from 1 to 2 147 483647 for identification of the first point and surface in the Cone Using the same number but with negative sign defines the surface and its mirrored counterpart in the XZ pane Y 0 A Cone will take up several point and surface numbers which must all be unique lt Radius gt 3 39 Radius of the Cone must always be greater than zero lt Revangle gt Revangle must be within the range 360 and different from zero If RevAngle is 180 a half cone is generated if its 360 a full cone is generated Positive revolution angles are defined counter clockwise lt Height gt The height must be different from zero If the height is less than zero the orientation of the cone is inverted Height is oriented in the Z direction on the figure The Cone example shown was generated with the following code HHH const N
26. com or Xx www intelliCAD com Google SketchUp http sketchup google com Xx AutoCAD www autodesk com 3DStudioMax http www discreet com X Rhinoceros www rhino3d com X There may also be other programs around capable of creating geometry data which can be used with Odeon Odeon supports a number of CAD entities which can be exported from these programs and imported directly by Odeon without any extra effort Depending on the modeling program used and indeed how it was used different approaches may need to be taken in order to ensure that all or most of the drawing data are exported to the DXF file in a form which can be understood by Odeon If Odeon encounter entities in the import process which Odeon recognizes but doesn t support then Odeon will notify about the problem The modeling programs should be 3D modeling programs Programs such as AutoCAD LT only have limited support for 3D modeling and are not recommend Programs such as AutoCAD 2002 IntelliCAD 6 Profesional Pro and 3DStudiomax are true 3D modeling programs and have been reported to be suited for the purpose Other programs may work as well but in any case you may have to experiment in order to find the optimum way to export and import the geometries from the programs About CAD drawings Room models to be used by ODEON must be surface models defined from plane surfaces no matter if the models are created in a CAD program or if they are modeled in the ODEON env
27. corresponding to grazing incidence on a smooth surface the correction factor reaches its maximum of two 6 80 A last remark on Oblique Lambert is that it can include frequency depending scattering at virtually no computational cost This part of the algorithm does not involve any ray tracing which tends to be the heavy computational part in room acoustics prediction only the orientation of the Ob ique Lambert source has to be recalculated for each frequency of interest in order to model scattering as a function of frequency 6 7 Sending rays from a source In ODEON Combined and Industrial version only there different kind of sources are available the point the line and the surface source Knowing a little bit about how ray directions and starting points are generated by ODEON may avoid confusion and help using tools like 3D Investigate Rays at its optimum Point Sources For Single Multi and Grid response calculations and for the 3D Investigate Rays display rays are sent in directions distributed as evenly as possible over a solid angle Ray directions are arranged in rings and ray 1 is sent out almost vertically downwards and the last ray is sent almost vertically upwards The total number of rays used is usually a few more or less than requested to ensure an even distribution For Quick Estimate and Global Estimate the send directions are chosen randomly allowing the calculation to be finished after any ray without getting a very une
28. distance and angle dependent and as such it is not known before the source and receiver are defined and the actual ray tracing or image source detection takes place An example on this is that a desktop may provide a strong specular component to its user whereas it will provide scattered sound at remote distances The method has several advantages not only does it make life easier because the same scattering coefficient can be used for different surfaces no matter their size it also allow better estimate of the actual scattering occurring at a reflection point because scattering caused by diffraction is not fully known before the actual reflections are calculated thus angles of incidence path lengths etc are known In order to allow these features to be included in predictions the reflection based scattering coefficient sr combining the surface roughness scattering coefficient ss with the scattering coefficient due to diffraction Sa is calculated individually for each reflection as calculations take place s 1 s d s The formula calculates the fraction of energy which is not specular when both diffraction and surface roughness is taken into account 1 Sa denotes the energy which is not diffracted that is energy reflected from the surface area either as specular energy or as surface scattered energy the resulting specular energy fraction from the surface is 1 Sa 1 Ss s Surface scattering Surface scattering is in the
29. eee ee eee a eee a renee ened 3 58 3 6 2 I testing Water tightness using 3D Investigate RayS cceeeeeeee eee eee eee eaetaeas 3 59 Ay Mate nial xxcccccccsdesesacececescvctetece dete a AA AOAR 4 60 4 1 Special MaterialS cvictccctviciescivectvectwetivandeatiatGadsdausdoudlaniduiddanechauduandvaudeandsoedeasdenedeanetet 4 60 4 2 Editing and extending the Material Library ccceccee cece eset eee eee eee eee eee ee eee eee e eas 4 62 5 AUPAliZatiOMm sesca ne r secete ne cesoteus sonete ne Gone Gene peceee ne tena ee netcnnge ne ec eenbo E 5 64 6 Calculation Principles herser rnar EEE Eaa 6 70 6 1 Global decay method Soricei a a aes 6 70 6 2 Quick EStimate sisas aane aE EE E E EEE E EE Mine eediee peek ieee tends 6 70 6 2 1 L Global Estimate c ccccccccscscssescsssccsssceecsssesassesecsssecasstasscsecssssiteasseeeeaseeaeans 6 71 6 3 Calculation of Response from Sources to Receivers 0ccceeseeeeeeeeeeeeeeeaeeeeseeeeeeeeeages 6 71 6 4 The Late ray reflection method of ODEON cccceceeeee eee e eee sees eee eaeeeeeeaeeeanenateeneenees 6 75 6 5 The Reflection Based Scattering coefficient ccc cce cece eect eee eee eee eee eee e teeta eens 6 75 6 6 Oblique Lambert vcccsccesecsceeces scce teas teneseececne teucerectenete neds cies nd teens a iadaa anaa 6 79 6 7 Sending rays from a SOUICE cece cece eee a anata teeta 6 81 6 8 Processing reflection data for auralization use i
30. energy so if the surface is in an exposed position e g the end of a balcony near the stage one should avoid for example simply replacing a quarter circle with a single plane at 45 which might then act like a reflector Concave curves naturally focus sound energy and since focussing is a fault we wish to model we must try to arrange that it be preserved However this does not mean that a large number of subdivisions are the solution Using many surfaces in the model will e Make the model visually complex and increase the probability of errors in the model typically small leaks may become a problem e Not combine with the image source theory used for the early reflections point sources e Increase the calculation time Subdivisions about every 10 to 30 will probably be adequate to reproduce focussing trends without excessive numbers of surfaces thus walls in a cylindrical room may be modeled from 12 to 36 surfaces A cylindrical column which disperses energy may probably be modeled from say 6 to 8 surfaces 3 1 4 What to model How to model an audience area Modeling each step between the rows in an audience area is not recommended the audience area can be simplified a lot without compromising the quality of the results in fact using one of the suggestions methods below is likely to produce better results Audience A Modeling the floor surfaces a Define the floor area below the audience b Assign appropriate
31. f jph Each extrusion surface has a set of array properties associated with it one set for each of the three main orientations in the room These properties can be found in the Surface editor and define how many times the surface should be repeated in each of the ha Soe iar C varena he ha hum ka am T iE f T h C Eina mer a LI eE ng reesi vera Lad eai or J i Laial POS ae Leen a i z mn main directions and the distances between i i E a the repetitions This feature is typically used io mee Tunis a a at in order to create a number of columns ye i o e a beams tables or chairs with a regular ec ke ra See ie ORE spacing When editing an array surface e g 1 do modifying a point all the repetitions of the ie i p j mee surface will be changed accordingly If i ore Gi ieee im individual changes are needed the arrayed om gm oe ee opa e surface must be exploded Once this Bal ey TS es fuir ae a Oe SR Le ba ep pe ae l operation has been carried out the surfaces in the arrayed surface has been turned into individual surfaces which can be modified surface by surfaces e g delete some of them It is not possible to perform the reverse of the explode operation so before exploding an arrayed surface make sure all operations common to the surfaces in the array have been carried out 3 50 Modeling a chair Z The easiest way to model RE hae cee eed a chair
32. following assumed to be scattering appearing due to random surface roughness This type of scattering gives rise to scattering which increase with frequency In figure 4 typical frequency functions are shown In ODEON these functions are used in the following way Specify scattering coefficients for the middle frequency around 700 Hz average of 500 1000 Hz bands in the materials list then ODEON expands these coefficients into values for each octave band using interpolation or extrapolation Set of scattering coefficients Z S 07 a a 0 015 os ca 0 06 S o5 0 25 oa a 0 55 5 M 08 03 gt lt 0 9 B 02 0 1 63 125 250 500 1000 2000 4000 8000 Frequency Hz Figure 4 Frequency functions for materials with different surface roughness The legend of each scattering coefficient curve denotes the scattering coefficient at 707 Hz At present it has not been investigated in depth which scattering coefficient at the mid frequency 707 Hz should be used for various materials However initial investigations indicate that the following magnitudes may be sound 6 76 Material Scattering coefficient at mid frequency Audience area 0 6 0 7 Rough building structures 0 3 0 5 m deep 0 4 0 5 Bookshelf with some books 0 3 Brickwork with open joints 0 1 0 2 Brickwork filled joints but not plastered 0 05 0 1 Smooth s
33. further To familiarise further with ODEON you should try to change some of the materials sources etc in the room and make new calculations A suggestion is to try changing the scattering coefficient on surface 2004 Rear wall behind audience from 0 7 to 0 05 and listen to the change in sound quality echo problems Create a copy of the room using the File Copy files option then make the changes to this room model In this way you will have results from both of the rooms present for comparisons Pre calculated Rooms Round Robins At this point you have tried the basic functions in ODEON and may want to view results for more realistic rooms A few pre calculated examples are covered in section 2 3 The examples include rooms which were used in the 2 and 3 Round Robins on Room Acoustic Computer Simulations along with the measured and simulated results 2 1 1 Summary of the calculation methods Global Estimation of reverberation time There are two calculation methods for the calculation of global reverberation time built into ODEON The two global estimation methods for reverberation times estimates reverberation time for the complete room with one selected source position zl Quick estimate is the fast method which is found in the Material List This method is based on the Sabine Eyring and Arau Puchades formulas and as such assumes diffuse field conditions Diffuse field cannot be assumed if e the room absorption is unevenly distributed
34. is defined and the distance between the source and the receivers are not the same for all receivers Please notice that one misplaced receiver may ruin the entire DL2 calculation thus it is a good idea to check the receiver positions or even better to check the individual results of the Multi Point calculation DL2 is given for the frequency bands 63 Hz to 8 kHz and DLz2 co is the A weighted Rate of Spatial Decay for the frequency bands 125 Hz to 4 kHz For DL2 as well as DL2 co the correlation coefficients are calculated If the correlation coefficients are low this may indicate bad locations of source and or receivers however it may also indicate a very low damping in the room the Spatial Decay Curve being almost horizontal The measuring points Receiver points and the source position are of course essential to the DL2 parameters and should follow ISO 14257 2 As an example a path of receivers may be chosen in the following distances from the source using logarithmic increment I 2 4 5 6 3 8 10 metres The positions should also follow the standard with respect to distance from floor and reflecting surfaces ODEON will use all the receivers defined in the receiver list In some cases the positions of the receivers will not combine with the receiver positions that should be used for the receiver path in the DL2 calculation In this case the following solution is recommended e Make a copy of the room using the File Copy files op
35. is set to TRUE e Odeon will not prepare the geometry for calculation as result the loading of rooms is speeded up e Odeon will enable debugging of parameters with the Debug statement The syntax for Debug is Debug lt debug string gt In effect anything can be put after the Debug keyword i e you may put a complete copy of a line in the par file there The contents following the Debug keyword is evaluated or if it can t be evaluated then echo ed directly to the debug window in Odeon when loading the geometry and it has no effect on the geometry If Debug sOn is set to FALSE then debug lines are ignored Contents in the Debug strings which can not be evaluated are displayed in quotes Example When loading the following par file into ODEON HH DeBuglsOn TRUE debug option turned on if DebugIsOn is set to false then Debug lines are ignored const L 6 Debug L debug a single constant const W 4 Debug const W 4 const H 2 7 Debug L W H Debug values of L W and H Box 1 L W H TB Walls floor and ceiling Debug Box 1 L W H TB Walls floor and ceiling Debug a complete line HH Odeon will create this Debug window as a response LITT icix DebuglsOn is TRUE at places in par file thus user defined Debug messages may be displayed in this window In order to prepare the geometry for calculations and skip debug messages the DebuglsOn flag must be FALSE everywhere in the par file Line 4 L 6 Line 6 const
36. may contain up to 10000 surfaces 3 30 Example CountSurf 1000 5 Beam in ceiling 1000 1100 1200 1300 will produce fives surface the first containing the numbers given in the ListOfPointNumbers the next surface with 1 added to all the corners in the list etc Of course all the points refereed to need to be defined typically this is done using a CountPr definition for each of the corners refereed to in the corner list of the CountSurf statement In the above example the points 1000 1004 1100 1104 1200 1204 and 1300 1304 need to be defined Sample room files Beams Par BeamBox Par BeamBoxWithWimdows Par Revolution surface RevSurf RevSurf must follow the syntax RevSurf lt FirstSurfaceNumber gt lt CurveStartl gt lt CurveStart2 gt lt SectionsInRevSurf gt lt Optional name gt The RevSurf command is typical used together with two CountPt statements to create a revolution surface using two curves of points The curves must contain the same number of points The RevSurf command will always create a number of surfaces each build from four points lt FirstSurfaceNumber gt A unique number from 1 to 2 147 483647 for identification of first surface in the revolution surface Using the same number but with negative sign defines the surface and its mirrored counter part in the XZ pane Y 0 lt CurveStartl gt First point number in the first revolution curve The curve of points is typically created using the CountPt
37. mean absorption coefficient are labelled Modified Sabine and Modified Eyring The mean absorption coefficients used for the Arau Puchades formula are derived in similar ways except that separate values for surface hits area and the corresponding mean absorption coefficients are calculated as projections onto each of the main axis of the room The Sabine Eyring and Arau Puchades formulae require a value for the room volume which ODEON estimates from the mean free path experienced by ray tracing using the well known relation Eeid S l 6 70 where V is the room volume and S the total active surface area From version Odeon 6 5 the ray tracing process carried out in order to estimate the room volume assumes scattering coefficients of 1 for all surfaces rather than using the coefficients assigned to the surface in the materials list as this is the mean free path formula is based on diffuse field assumptions The value of S used here is the sum of the areas of non transparent surfaces taking into account whether one two or indeed none of the sides of a surface are visible inside the room Convergence criterion A certain number of particles must be sent out and followed around the room for a stable estimate to be obtained More and more particles are sent out in random directions until the value of the reverberation time has remained within 1 for at least 50 particles At the end of a run the data on how many times each surface was hit is
38. minimum there must be 1 36 8 lines in a full input file e 1 line is vertical upper plot O 12 o clock plot when looking at the source e g at a loudspeaker membrane 10 line is horizontal left plot 90 9 o clock plot 19 line is lower vertical plot 180 6 o clock plot 28 line is right horizontal plot 270 3 o clock plot An example Full_Omni dat on the full input format can be found in the DirFiles directory created at the installation of ODEON When the directivity pattern is rotationally symmetric The first non comment line of the file should start with the word SYMMETRIC In the SYMMETRIC case there is one line of data for each frequency As a minimum there must be 1 8 lines in a symmetric input file 10 96 Examples of SYMMETRIC sources are a Trumpet and the Omni directional source An example Symmetric_Omni dat on the SYMMETRIC input format can be found in the DirFiles directory created at the installation of ODEON Samples on directivity patterns TLKNORM TLKRAISE and Soprano ref 42 The TLKNORM source type corresponds to a male talker with a normal vocal effort The gain and EQ fields in the Point source editor inside ODEON should be set to zero This source is also a reasonable approximation to a female talker except that the 63 and 125 Hz band should be ignored To simulate a trained talker addressing an audience in a raised voice use the TLKRAISE source This has the same directivity as TLKNOR
39. new sets for use with ODEON Binaural recording Humans usually listens using two ears This allows us to perceive sound as a 3D phenomenon To create a binaural recording its not enough to create a two channel recording stereo also the colouration created by diffraction from the human body has to be included This is usually done by using a dummy head with a microphone mounted at the entrance of each ear canal this recording may be recorded using an ordinary stereo recorder but is now refereed to as binaural Binaural recordings are usually played back through headphones to avoid colouration from the room in which it is played as well as avoiding diffraction from the human body to be included twice at the recording and at the playback If one has measured or indeed simulated the BRIR s see below in a room it is possible to simulate a binaural recording BRIR Binaural Room Impulse Response The BRIR is the key to binaural room acoustic auralization The BRIR is a set of impulse responses detected at the left and right entrance of the ear canals of a dummy head or indeed at blocked entrenches of the ear channels of a living person residing in a room when a sound source or some sound sources has emitted an impulse The BRIR should include all the necessary information on receiver position and orientations source s position s and orientations room geometry surface materials and the listener s geometry described by t
40. one of the most important room acoustical parameters so it is important that levels at which auralization samples are presented are realistic If playing a simulation of voice at an unrealistic high level the speech intelligibility may be over judged it does not help that Clarity or Speech Transmission Index is satisfactory if the Sound Pressure Level is too low If play back levels are too high echo problems may be exaggerated because echoes that would be below audible threshold or at least at a very low level are made audible The levels presented in auralization samples created by ODEON are influenced by e The HRTF s e Level in input signal file e g the RMS value or Leqa Calculated Sound Pressure Level which is based on geometry sources receiver positions materials etc Overall recording level in the Auralization setup Red Lev in the Auralization display of the JobList if off line convolution is used Mixer levels Mix Lev in the JobList if off line convolution is used Gain in the Streaming convolution dialog if the real time convolution option is used Output gain of the soundcard the volume setting Sensitivity of the headphones Coupling between headphone and the subjects ear Maximised play back levels for maximum dynamic range If you are only interested in the best sound quality in your auralization files you may focus on getting an Output Level Out Lev in the auralization display within the Job list as close t
41. org 10 1 File location for directivity files No matter if files are in the CL1 CL2 or in Odeon s native So8 format the files should be stored in Odeon directivity directory which is specified inside Odeon at Options Program setup Directivity files location The files may be stored in subdirectories to this directory allowing loudspeaker directivities of different brands to be located in separate directories e g C odeon DirFile ManufacturerA or C odeon DirFile ManufacturerB We have taken the opportunity to create a number of folders for manufactures which do supply loudspeaker directivity files in the CLF format Using these predefined directories it is easier to move a room from one PC to another without breaking file linkage 10 2 Creating new directivity patterns in the Odeon So8 format Tools for creating directivity patterns in the Odeon So8 format can be found at the Tools Creating directivity patterns menu entry inside the ODEON program The tools allow you to expand the set of source directivity pattern files available for point sources in ODEON The ODEON directivity pattern file Version 3 or later contains information on the sound levels for the eight frequency bands 63 Hz to 8 kHz in dB for each 10 azimuth and 10 elevation These files are binary and have the extension SO8 An example on a directivity pattern is the pattern stored in OMNI SO8 10 3 Entering a directivity plot using the Directivity plot editor
42. parameters and symmetric modeling syntax signs on point and surface numbers The symmetric modeling syntax means less typing and less typing errors Parametric sample BoxFromParametersUsingSymmetricModeling par HHH const W 4 const L 6 const H 2 7 Pt 1 0 W 2 0 Pt 2 L W 2 0 Pt 11 0 W 2 H Pt 12 L W 2 H Surf 1 floor 1 2 2 1 Surf 2 ceiling 11 12 12 11 Surf 3 end wall 1 11 11 1 Surf 4 end wall 2 12 Mirror Mirror works just as well defines point 12 and 2 Surf 5 side wall 1 2 12 11 HHH Below the box shaped room is modeled using the Box statement which is the easiest way to create this simple geometry A MTranslate statement is used to insert the Box at the same position as in the three other examples Parametric sample BoxStatement Par HHH const L 6 const W 4 const H 2 7 MTranslate 1 2 00 3 44 Box Ilwh tb Walls and floor HHH Modeling a cylinder This example shows two different ways to create a cylindrical room with a floor and a ceiling In the first example the room is modeled using the Cylinder statement Parametric Sample CylinderStatement Par HHH const N 16 const R 15 const H 10 Cylinder 1000 N R 360 H TB Cylindrical room HH The Cylinder statement is of course the easiest way to model a cylinder however sometimes more flexibility is needed e g different radius in top and bottom In the second example the corners in the room are modeled using the CountPt statement and the cylindr
43. possible to add a number of points to a point list e g another PList to a PList In the following example PList1 is assigned the points 100 110 120 130 140 150 160 170 180 190 200 10 11 12 13 15 Plist PlistO 10 gt 13 15 A point list can be referenced in the following way adding point 1 before and 2 after the list in this example Surf Test_surface 1 PListO 2 To reset the list use the statement list O used in this example ResetPList0 Multi Surface MSurf The multi surface MSurf is essentially just a variant of the Surf statement Instead of typing one header line e g Surf 1 A surface name for each surface the header can be shared by multiple surfaces MSurf lt SurfaceNumber gt lt NumberOfSurfaces gt lt Optional Description gt lt ListOfPointNumbers1 gt lt ListOfPointNumbers2 gt lt ListOfPointNumbers3 gt liiis lt NumberOfSurfaces gt lines with lists of points describing each surface lt SurfaceNumber gt A unique number from 1 to 2 147 483647 for identification of the surface Using the same number but with a negative sign defines the surface and its mirrored counter part in the XZ pane Y O The surface number may be defined using mathematical expressions lt NumberOfSurfaces gt The number of surfaces in the surfaces in the MSurf lt Optional Description gt A string displayed and printed for easy identification of the surface Could be something like Main floor 3 27 Example on multi surfac
44. read the contents of a directivity file Select File Create ASCII file from SO8 file e Open the SOU file you which to read e Open the newly created ASCII file e g C AODW DirFiles Omni Asc using a text editor like NOTEPAD This may be useful for instance to see how the interpolation of the polar plots worked out The generated ASCII output file will use the separating character specified from within the ODEON program OdwCombined Exe OdwAuditorium Exe or Odwindustrial Exe from the dropdown menu at Options Program setup ASCII output The character will be inserted between each value in the output file The default separator is a single space The file generated is an ASCII file containing the values in SPL at 1 metre defined in the input file The format of the file is the same as that of an input file of the FULL type 10 97 Appendix A Mathematical expressions available in the Par modeling format Constants variables point numbers surface numbers and coordinates may be defined using mathematical expressions Where integer numbers are expected Counter ranges in for end loops point surface numbers etc the results of mathematical expressions are automatically rounded to the nearest whole number Operation Syntax Example Addition 2 5 7 Subtraction 3 1 2 Multiplication A 2 3 8 Division 4 2 2 Power Base Exponent 2 3 8 or or Power Exponent Base Powe
45. rig gee ee eee D Loi el Yo ia LE pepe ere E iad betel iaDia rA E w T i wx Temi ber e mes re r a ra SSS P nmi heg P iep Haji niy Hee D lm Start the program a shortcut to the program is found at the Windows Menu Start Programs Odeon OdeonExtrusionModeler Initial settings Before starting modeling geometry select the drawing plane which is best suited for the geometry to be modeled Also select properties for grid and snap spacing Drawing an extrusion surface Left click the mouse at the positions where the points in the surface are desired if no points and lines are generated then you need to bring the current surface in edit mode using the Insert or Esc shortcut or by double clicking a point in the surface Once all points in the surface have been defined finish the current surface by starting a new one using the Ctrl A shortcut or pressing the Insert or Esc shortcut To assign a drawing depth X Y or Z and an extrusion dX dY or dZ select the surface in the Surface editor table where it can also be specified whether the surface should have a bottom and a top and a Description may be entered The drawing depth and extrusion for each extrusion surface is displayed graphically at the bottom of the application window Editing or correcting an extrusion surface In order to make corrections to an extrusion surface select it in the Surface editor table and bring it into edit mode using the Insert or Esc shortc
46. slope of the backwards integrated octave band curves The slope of the decay curve is determined from the slope of the best fit linear regression line between 5 and 35 dB obtained from the backwards integrated decay curve Early Decay Time EDT is obtained from the initial 10 dB of the backwards integrated decay curve Sound Pressure Level Clarity Deutlichkeit LF STearty STiate ANd STiotar The energy of each reflection is added to the appropriate terms in the formulas for all the energy parameters according to its time and direction of arrival After the response calculation Clarity Deutlichkeit Centre Time Sound Pressure Level Lateral Energy Fraction STearly STiate and STtota is derived In the following formulae Ea b is the sum of energy contributions between time a and time b after the direct sound time is the end of the calculated response and f is for the reflection arriving at time t the angle between the incident direction and the axis passing through the two ears of a listener Below two definitions are shown for Clarity Deutlichkeit Lateral Energy Fraction STearly STiate and STtota Corresponding to the Room Setup Calculation parameters Smooth early late ratios option being checked or not The smoothing is turned on by default The averaging is equivalent to a smoothing of the transition between early and late energy and attempts to make up for the facts that 7 83 e Reflections in ODEON are p
47. subscribing the room if the construction part which the fractional surface is part of is considerable smaller that the room box the scattering might be underestimated and a higher scattering coefficient should be assigned to the surface e Transmission is for walls which transmit sound to another room When this wall type has been selected it is possible to edit the transmission data to specify the reduction index transmission loss and to link the wall with another surface in case the wall is composed of two parallel surfaces with a distance between them and possibly with different surface materials on either side When the Transmission type is assigned to a surface 50 of the rays hitting the surface will be reflected and 50 will be reflected the energy calculations are accomplished by multiplying each ray or particle with the appropriate frequency dependent energy parameters Transmission is covered in appendix D Surface name Lists the name given to the surface in the surface file if given any name Area Lists the calculated area for each surface 4 2 Editing and extending the Material Library The materials displayed in the left side of the Materials List window resides in an ASCII file called Material Lis This library provided with ODEON may be altered and extended at will by the user using the material editor available from the Material list If you should wish to add several materials e g by copying them from some other fi
48. than 35 dB For reliable results it is recommended to use an Impulse response length which is comparable to the reverberation time Impulse response resolution Job calculations and Global Estimate The Impulse response resolution is the width of the steps in the Impulse response histogram in which the energy of the reflections are collected during a point response calculation The histogram is used for calculation of EDT and Tso A resolution of approximately 10 ms is suggested Transition Order Job calculations only The calculation methods used in Odeon 8 has been heavily updated therefore recommendations given for the transition order TO in earlier editions of Odeon does not apply anymore The transition order applies only to point sources Below the transition order calculations are carried out using the Image Source Method above TO a special ray tracing algorithm is used see section 6 4 Currently our safe recommendation on the transition order is a transition order of 2 although it does not seem to be very critical anymore Transition order 0 If a transition order of zero is selected then point responses will be calculated using ray tracing only A TO of zero should be chosen for rooms with many fittings e g work rooms with many machines etc 8 88 Transition order gt 2 It seems that quality of results can be improved slightly for rooms such as fan shaped halls with little diffusion if using a TO as high as 5 or
49. the cylinder is always the centre of the floor bottom surface Connection points The foot points in Cylinder are stored in PlistA The top points in Cylinder are stored in PListB The example shown was generated with the following code CylinderStatement Par HHH const N 16 const R 15 const H 10 Cylinder 1000 N R 270 H TB Cylindrical room Ht Hint The cylinder can be made elliptical using the MScale statement 3 38 The Cylinder2 statement Cylinder2 is a cylinder shell of the calotte type Rather than specifying the radius and revolution angle Cylinder2 is specified in terms of the width and height Cylinder2 is typically used for cylindrical curved ceilings The syntax for Cylinfer2 is Cylinder2 lt Number gt lt NumberOfSurfaces gt lt Width gt lt Height gt lt Length gt lt T B N gt lt optional name gt lt Width gt Width is oriented in the X direction on the figure lt Height gt Height of the cylinder shell is oriented in the Y direction on the figure and may be positive concave shell as well as negative convex shell Height must be different from zero and less or equal to Vo Width lt Length gt Length of the cylinder shell is oriented in the Z direction the figure If Length is negative the orientation is inverted Insertion point The insertion point of Cylinder2 is always foot point of the calotte floor bottom surface Connection points The foot points in Cylinder2
50. the points it is referencing out comment them e Reload the room Problem with display of coordinate system The blue coordinate system looks odd or behaves strangely Solution If the Origo is situated in a point far away from the geometry the coordinate system may not display properly when projection is turned on in that case turn off the projection using the P shortcut In order to fully solve the problem the position of the origo should be altered as described in the example above 3 56 The geometry displayed in the 3DView appear to be too small or large after re import If the geometry was initially imported using an incorrect unit then Odeon has defined its default view list in the 3DView in order to display that initial version of the geometry correctly To reset the view list use the Ctrl DEL Shortcut from within the 3DView 3 5 Model check in ODEON The geometry file is the first file used by ODEON when assigning a file from Files Open Room model When assigning a new or modified room its validity is checked The check performed by ODEON involves checking whether data is consistent and in the correct format but not whether a meaningful geometry is being defined If the geometry passes then you may start checking if the geometry is meaningful and without errors This may involve Viewing the room in a 3DView Viewing the room in the 3DOpenGL display Analysing the geometry for unacceptable surface warps in the 3DGeometry De
51. the scattering assigned to the surfaces Click the Ok button then click the Single forward button a few times and note the behaviour of the ray tracing 3D Billiard The 3D billiard display is a tool that can be used for investigating or demonstrating effects such as scattering flutter echoes or coupling effects A number of billiard balls are emitted from the source and reflected by the surfaces in the room To speed up the process set the Dist per update to a higher value To visualize a flutter echo a large Number of billiard balls should be used e g 10000 balls It s easier to visualize a flutter echo if rays are only emitted in the relevant plane XZ YZ or XY If the geometry is complicated it may be hard to see the billiard balls in that case toggle parts of the geometry off using the T shortcut Auralization Listening to the rooms At this point you have tried calculation of room acoustical parameters operating visual display like decay curves 3D reflection paths reflectograms etc Its time to move on trying the auralization options in ODEON Two ways of auralization are available in Odeon a real time streaming convolution which produces one or two channel auralization on the fly with some latency and off line convolution allowing auralization with up to 25 simultaneous channels which may be assigned individual signal delay and level The result of the off line convolution is stored in files for later playback Off line A
52. this example point 1 and point 23 are identical If an elevation surface has 22 surfaces then 23 points must be made available to the ElevSurf as in this example HHH MPt I 23 000 7 48 10 76 14 64 64 78 2 68 51 52 49 62 2 02 48 22 1 1 45 3 2 68 3 28 43 85 1 45 42 40 40 98 1 45 0 34 5 000 ElevSurf 1 1 22 2 7 walls Surf 200 Floor I gt 22 Surf 201 Ceiling 24 gt 24 22 1 HHH Elevation surface 2 Use the ElevSurf2 statement to define a series of vertical surfaces from a series of perimeter points plus an elevation height The perimeter points are typically defined using the MPt statement The syntax of ElevSurf2 is ElevSurf2 lt FirstSurfaceNumber gt lt FirstPointNumber gt lt SectionsInElevSurf gt lt Height gt lt T B N gt lt Optional name gt The ElevSurf2 only differs from E evSurf in that a top and bottom surface may be specified the T B N option lt FirstSurfaceNumber gt A unique number from 1 to 2 147 483647 for identification of the first surface in the E evSurf2 surface Using the same number but with negative sign defines the surface and its mirrored counter part in the XZ pane Y 0 lt FirstPointNumber gt First point number in the floor perimeter The floor points are typically MPt statement See example below lt SectionsInElevSurf gt The number of surfaces to be created by the FlevSurf2 statement If creating a cylinder a nu
53. to View Grid Response results as well This topic will be covered below Bbetine a receiver grid and calculate grid response Enter the Define Grid menu and select the floor surfaces surface 1001 and surface 1002 Specify the Distance between receivers to 2 metres then click the Show Grid button Note If the Define Grid button is disabled this is because some process is open which requires data to be saved In this case it is probably the Estimate Reverberation display that needs to be closed To find this open window use the Windows menu item on the menu bar Other displays containing calculation processes may cause the same kind of disabling of miscellaneous options Close the Define Grid dialog to save the grid definition Calculate grids Click the Job list button again Activate Grid option from the Job List check the Grid option for job 1 4 and click the Run All button ODEON will now start calculating the grid response for the four jobs this may take a while When the calculations have finished select job number 1 in the Job List and click the View Grid Response button to view the grid results To learn more about the results and options available from this display use the F1 shortcut 3D Investigate Rays 3D Investigate Rays visualises the ray tracing as it is carried out during any point response calculation By default its calculation parameters are also set up as the parameters used for the point response calculations
54. which was created and worked fine in one of the above listed versions of Odeon this is probably due to a change that has been made to the surface numbering mechanism applied in Odeon The numbering mechanism has been changed slightly in order to avoid a conflict which appeared when using symmetric surfaces along with modeling entities such as CountSurf Box Cylinder etc and in particular to make the automatic surface numbering work without any problems when the NumbOffSet is set to Auto If having problems loading a room due to the reasons just mentioned Odeon will either give an error message that surfaces are repeated in the geometry file or that materials are not applied to all surfaces In these cases you may wish that Odeon use the old numbering mechanism this can be done using the Version4 flag in the par file As the first line in the geometry file just after the sign type Version4 TRUE 1 3 2 Short guided tours This chapter will give an introduction to the use of the ODEON program Depending on the edition purchased the guided tour differs The Combined and Auditorium editions are covered in section 2 1 and the Industrial edition is covered in section 2 2 Buttons hints and menus The most common operations can be carried out using buttons Pointing the mouse on a button will display a small bubble telling the function of that button a hint You can also operate the program using menus or shortcut keys
55. with larger areas Do note that some surfaces based on poly faces may not import correctly un ess the glue option is turned on ODEON will not combine surfaces with each other when they are situated on different layers in the CAD drawing thus if you wish that certain surfaces are not glued together e g if upper and lower part of a wall should be assigned different materials either draw the surfaces on different layers in the CAD program preferable or turn off the glue surface s option may lead an excessive number of surfaces and may not work with poly faces Max point margin If points in the DXF file are within this margin the points will be considered equal Allowing a certain amount of point margin will allow the Glue function to perform better if the coordinates in the model are not exact However if you have modeled both sides of a surface e g outside and inside surface of a balcony front edge the Max point margin should be smaller than the distance between these surfaces otherwise the points on either side of the surface will be considered the same with disastrous results Max warp ODEON will split four point surfaces into 2 three point surfaces if the surface s warp exceeds this value The glue option on the other hand will try to glue surfaces as long as this does not lead to a surface exceeding then max warp 3 55 3 4 3 Editing the imported geometry It may be necessary or at least desirable to make changes to g
56. 0 or fully absorptive Material 1 Go into the Materials List and assign e g 20 absorption to all surfaces use Ctrl Ins to do this in one keystroke e Place a source somewhere inside the room Sources are defined from the Source receiver List At first it may be a good idea to define a point source somewhere in the middle of the room Open a 3D Investigate Rays display and run it with e g 1000 rays with a Max reflection order of zero This tests whether any holes can be seen from the source position and should reveal any gross problems The tracks of lost rays will show outside the room boundaries and indicate whereabouts in the room problems occur If rays are being lost and you have an idea of which part s of the room is are leaky a number of things may be done e Reduce the value of Max accept warp in the Room setup at the ModellAir conditions page Then run the 3DGeomtry Debugger Warnings will appear if surfaces have a warp or an overlap above the acceptable range This may reveal slight warps of surfaces in the leaky region of the room which then have to be reduced as far as possible by revisions to the geometry file e Use the 3DView or 3DOpenGL for inspection of the model to study the region s under suspicion It may turn out that a surface is missing or does not join to its neighbours in the expected manner It may help to zoom regions in question with the Highlight surfaces Show corner numbers and coords and Modeling
57. 595 30 Leo L Beranek Takayuki Hidaka Sound absorption in concert halls by seats occupied and unoccupied and by the hall s interior surfaces J Acoust Soc Am 104 December 1998 p 3169 3177 31 Rindel J H Modeling the Angel Dependent Pressure Reflection Factor Applied Acoustics 38 p 223 234 32 Bill Gardner and Keith Martin MIT Media Lab HRTF Measurements of a KEMAR Dummy Head Microphone http sound media mit edu KEMAR html 33 William H Press Brian P Flannery Saul A Teukolsky William T Vetterling Numerical recipes in Pascal The Art of Scientific Computing Cambridge University Press 1990 34 Affronides Sophocles Introduction to Signal processing J Prentice Hall International 1996 35 Oppenheim Alan V Schafer Ronald W Descrete Time Signal Precessing Prentice Hall International 1989 36 Music for Archimedes CD B amp O 101 1992 37 Anechoic Orchestral Music Recordings Denon PG 6006 1988 38 Ming Zang Kah Chye Tan M H Er Three Dimensional Sound Synthesis Based on Head Related Transfer Functions Centre for signal processing School of Electrical and Electronic Engineering Nanyang Technological University Singapore 639798 39 Bork Ingolf A Comparison of Room Simulation Software The 2 Round Robin on Room Acoustical Computer Simulation Acta Acoustica Vol 86 2000 p 943 956 40 Bradley J S Predictors of speech intelligibility in rooms J Acoust Soc Am
58. 6 however not if only few rays are used in the calculation Smooth early late rations Job calculations only A smoothing procedure is normally applied when calculating Cso D STeary STiate and STtota and LFso to simulate the filtering in real measurements as well as the smearing that happens to real life reflections The Smooth early late ratios option is by default ON Smooth late decays Job calculations only Causes a curve fitting and smoothing procedure to be applied to the reverberant decay giving better appearance to the late part of the decays The smoothing is a way of simulating that the number of reflections increases with respect to time as it would it in real rooms The Smooth late decays option is OFF by default and doesn t improve the quality of results except for the visual appearance of reverberation curves Desired late reflection density Job calculations only Determines the reflection density which ODEON will attempt to achieve in the late portion of the decay for Single and Multi Point Response calculations The higher this value is the smaller is the chance that unrealistic peaks will disturb the late part of the decay curve using the default value of 100 ms will usually be sufficient To achieve the highest possible density turn off the Decimate late rays option use a high number of rays and a high Desired reflection density You will find a separate value for the Desired late reflection density on the De
59. Acoustic Computer Simulations Geometry absorption data source and receiver positions as well as the measured room acoustical parameters are those supplied to all participants in the Round Robins by the PTB in Odeon 1985 2005 Germany these data are publicly available at www ptb de To compare results calculated by Odeon with those measured in the real rooms e Open the room in question e Open the JobList the Shift Ctrl J shortcut e Select one of the pre calculated Multi point response jobs job one or two in the Joblist and open it the Alt M shortcut e Select the Measured versus simulated tab sheet in the Multi Point display A couple of other examples Hagia lrene par is a model of a Byzantine church in Istanbul which like the examples above also includes the measured room acoustical parameters Another example Studstrup par is also available this is a model of a turbine hall at a power plant measured SPL A is included in that example This example is only available for the Auditorium and Combined editions If you wish to carry calculations faster you may enter the Room setup and select the Engineering setting this will provide results approximately 5 times faster without much loss in quality in results Other facilities in ODEON Apart from the features which have been demonstrated in the above tour ODEON also contains facilities for e Calculation of transmission through walls thi
60. Congress and Cultural Centre Architect zg r Ecevit Acoustics Jordan Akustik Denmark ODEON Room Acoustics Program Version 9 0 Industrial Auditorium and Combined Editions by Claus Lynge Christensen ODEON A S c o Acoustic Technology rsted sDTU rsteds Plads Technical University of Denmark Building 352 DK 2800 Lyngby Denmark www odeon dk 2007 Introduction This manual is intended to serve as an introduction on modeling room geometries in Odeon to the facilities in the ODEON software and to the calculation principles applied in ODEON It will not cover in depth all facilities included in the Odeon software explanations of displays calculation parameters results etc are available as context sensitive help from within the Odeon applications shortcut F1 It is recommended to use the online help to learn about the specific features available from the different displays the interpretation of results calculation parameters etc The contents of this manual are as follows Chapter 1 covers installation of the program changes from previous versions etc Chapter 2 is a Short guided tour introducing the ODEON program and its facilities offering a short guided tour to the operation of the program including specification of calculation parameters definition of receivers receiver grids different kind of sources and the presentation of results Section 2 1 is intended for the Auditorium and Combined editions Secti
61. DEON program Measuring HRTF s is however a complicated task so you will probably be using the supplied ones If you should be interested in creating own sets of HRTF s for Odeon additional information can be found in the help available from within the Odeon program The imported HRTF s to use for auralization are pre filtered into octave bands in order to reduce calculation time The octave band filter parameters for the selected filter bank can be seen on the filter bank name at the Auralization Setup menu The filter parameters are M The M value is taken into account if the Apply enhancement option is checked If the file name contains the word Mddd where ddd is a floating point number then localization enhancement was applied to the HRTF s 38 This means that frequency dip and notches in the individual HRTF s has been exaggerate in order to improve the directional cues in the HRTF s The M factor determines how much the dips and notches has been exaggerated If M is O then the effect is neutral a value of 3 0 improves localization without too much undesired colouration A M value greater than 3 0 does not seem to give any noticeable advantages whereas a value less than 3 0 give less colouration The enhancement algorithms are further developments of those used in earlier versions of Odeon as a result the M factor can be set as high as 3 allowing a significant improvement of the 3D experience through headphones without noticeable draw
62. DSOLID REGION and BODY entities are not supported by ODEON try using one of the approached listed above in order to make the geometry compatible A final remark is that it is always a recommended practice to make backup copies of your CAD files before making any conversions 3 4 2 Performing the import in Odeon To import a DXF file e Select Files Import from file dxf 3ds cad or simply drop the file on the Canvas of Odeon e Specify the input file e g MyCADRoom dxf e Specify the destination file e g MyCADRoom Par One the file names have been specified the Import DXF file dialog appears allowing miscellaneous import options to be specified By default most of the parameters may be left untouched however it is important that the correct drawing unit is specified If the geometry does not appear as expected you may try other input parameters Unit in input file Unfortunately dxf files are unit less It is important that the correct unit in which the geometry was modeled is selected in the import dialog If the correct unit is not specified the import process may fail because the geometry seems to be only a few millimetres large or several kilometres in size Geometric rules glue surfaces Surfaces imported in the DXF format are put simple by nature surfaces build from three or four sets of coordinates When the glue option is turned on ODEON will try to glue or stitch if you wish these surfaces in order to form fewer surfaces
63. Downloaded from orbit dtu dk on Dec 18 2015 oe Technical University of Denmark W Industrial Auditorium and Combined Editions Version 9 0 User Manual Odeon Room Acoustics Program Christensen Claus Lynge Publication date 2007 Document Version Publisher final version usually the publisher pdf Link to publication Citation APA Christensen C L 2007 Industrial Auditorium and Combined Editions Version 9 0 User Manual Odeon Room Acoustics Program Kgs Lyngby Odeon A S General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights e Users may download and print one copy of any publication from the public portal for the purpose of private study or research e You may not further distribute the material or use it for any profit making activity or commercial gain e You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details and we will remove access to the work immediately and investigate your claim A ODEON Room Acoustics Program Version 9 0 User manual Industrial Auditorium and Combined Editions Front figure The Opera House project for Ankara
64. In this guided tour we shall define point line and multi surface sources although only the point source is relevant to this auditorium type of room Finally we define a receiver Click the Source receiver list button at the toolbar to open the Source receiver list from which sources and discrete receivers are defined If the Source receiver list is already open but hidden behind other windows etc clicking this button will rearrange the program windows as needed Define a point source Click the New point source button in the local toolbar at the right side to open the Point source editor Enter the values x 3 metres y 2 metres and z 1 2 metres If you are not sure of the position of the source you can select the 3D Edit source display If you do so you should notice how the menu item 3D Edit Source appears on the dropdown menu when this window becomes active The 3D Edit Source Receiver menu will allow you to operate the 3D display e g use the SPACE key to switch between different predefined views Finally set the overall gain to 65 dB 65 is just an arbitrary value To save the new source just close the Point source Editor and confirm New sources are by default turned OFF therefore it will not be visible in the 3D Edit source display Press the SPACE key to activate the source for the current Job more on Jobs later on If you are running the Auditorium edition of ODEON define two extra point sources of your own choice a
65. M but the levels in the eight octave bands are respectively 2 2 5 7 9 8 6 and 6 dB higher The directivity pattern of Soprano ref 42 is the directivity of a soprano singing opera 42 Comments and empty lines Lines containing comments and empty lines may be inserted anywhere in the file as long as they do not come between data items which should occur on one line Comment lines must begin with a colon an semicolon or an asterisk 10 5 Compatibility with previous versions of ODEON The directivity files of ODEON 2 6D and earlier having the file extension SOU is based on the six octave bands 125 to 4000 Hz where ODEON version 3 or later is using the eight octave bands 63 to 8000 Hz Thus new files have to be created containing the information for the eight bands The levels for 63 and 125 Hz will be equal just copied and the levels for 4 and 8 KHz will be equal just copied To create a directivity pattern for ODEON 3 or later e g OMNI SO8 from an ODEON 2 6D directivity file or earlier e Select File Translate 6 band into 8 bands e Open the old directivity file e g OMNI SOU The new directivity pattern file OMNI SO8 will automatically be saved at the default path for directivity pattern files e g C ODW6_O Dirfiles This path is specified from within the ODEON program at the toolbar dropdown menu Options Program setup 9 3 Making a readable text file from a directivity pattern file SO8 To
66. N are stored in uncompressed wave files having the well known wav extension Most if not all resolutions are supported so files edited by programs such as CoolEdit or Adobe Audition can be used without any conversion being required 5 67 8 16 24 32 bit PCM 32 bit IEEE Float 8 16 24 32 bit PCM Extensible tells the number of significant bits 32 bit IEEE Float Extensible includes some additional info which is not used for input by ODEON To be compatible with the HRTF s supplied with ODEON the wave files should always be at a 44100 Hz sampling frequency The ODEON program comes with a few anechoic samples which are installed to the odeon WaveSignals directory If you wish to extend the library of input signals you should put your new signal files here or in a subdirectory to this directory e g odeon WaveSignals English voice or odeon WaveSignals NoiseSignals A few audio CD s containing anechoic recordings are commercially available namely the Archimedes CD 36 which contains some recordings of solo instruments and the Denon CD 37 which contains semi anechoic stereo recordings of orchestral music The easiest way to transfer recordings on an audio CD into wave files on the harddisk on a computer is probably to use a software application known as a CD ripper this also ensures the transfer is without loss in quality Signals ripped from CD audio tracks will always be in two channels if you know tha
67. The easiest way to enter a new directivity plot is to use the built in plot editor which allows building a directivity plot from a vertical and a horizontal plot Enter the dB values for the horizontal and vertical plots at the selected frequency band in the corresponding tables The angular resolution is 10 degrees If data are not entered for all angles e g if the data are not available Odeon will do interpolation between the angles entered For angles between the polar plots Odeon will perform elliptical interpolation Calibration Three different options are available e f No calibration is selected Odeon will use the dB values as entered in the table adding the equalization values entered e f Calibrated source is selected Odeon will add the equalization entered then shift the resulting SPL s of the source in order to obtain a sound power level of O dB re 10E 12 Watt at the selected Calibration frequency band This calibration type is typically used for generic source types such as the OMNI or SEMI directivity pattern e f Sensitivity calibration is selected the SPL s of the source will be shifted in order to obtain the SPL is Sensitivity calibration dB on axis of the source at the distance specified as Ref distance metres Maximum dynamic range The minimum level will be Max level minus Maximum dynamic range If the range is large the display may not be optimum in the directivity viewer The source w
68. To obtain the easiest operation inside ODEON the following orientation should be used using a concert hall as the example e X axis pointing towards the audience e Y axis pointing to the right as seen from the audience e Z axis pointing upwards The syntax is CoordSys lt X gt lt Y gt lt Z gt where X Y Z indicate which axis should be used as the x y and z axis inside ODEON X Y and Z may also have a sign to indicate that the axis should point in opposite direction the Example 1 the default orientation which is assumed by ODEON if the CoordSys statement is not used in the geometry file CoordSys X Y Z Example 2 changing the direction of the X axis CoordSys X Y Z Example 3 Swapping the X and the Z axis CoordSys Z Y X Example 4 The CoordSys statement may be used more than once in the same par file HH CoordSys X Y Z je g if the X axis was inverted in imported model data sresetting the coordinate system to the default CoordSys X Y Z s model data appended in the Odeon editor modeling environment sit is most practical if using the default Coordinate system when modeling in the Odeon environment then coordinate system will have the same orientation in the Odeon editor as well as in the 3DView inside Odeon siise model data i model data HHT User coordinate system The UCS command is mostly there for compatibility with previous versions of ODEON the coordinate manipulation function
69. Version onto your computer Upgrading your software license The program Noise Explorer is used here for upgrading Odeon software licenses The hardware HASP key contains coded license information that is used to unlock the different software To upgrade your license install Noise Explorer from the Install Noise Explorer folder onto your computer and make sure the hardware HASP key is attached to the USB port a Run the Noise Explorer program b Choose the Tools menu and select License Utility c A window appears showing what licenses are installed on the hardware HASP key d Note down the Key Identification code top right corner of the window e This Key Identification code must be given to Bruie amp Kj r when an upgrade is ordered so a new license code can be generated When you have received your new License Code a Start the Noise Explorer program b Choose the Tools menu and select License Utility c Type in your newly received code in the License code field d Press Install e Close the dialog box You can now use all the facilities of the new version of the software a Run the Setup exe program from the Combined Auditorium or Industrial directories and follow the instructions during the installation process this will install the relevant edition of the ODEON program onto your computer b To run the program the supplied hardware key must be inserted into one of the USB ports on the PC 1 2 Tr
70. W 4 4 4 Line 8 L 6 W 4 H 2 7 0000000000000032 e 11 Box 1 1 L 6 W 4 H 2 70000000000000032 TB Walls floor and ceiling 3 2 2 Creating a new Par file time saving hints The golden rule when creating a Par file to model a room is to think carefully before you start typing For very simple rooms it is not too difficult to keep track of things but for realistically complex rooms a systematic approach is desirable You will typically have a set of drawings which have to be used as the basis for the ODEON model It pays to spend quite a long time working out how the room can be simplified to a manageable number of sensibly shaped plane surfaces sketching over the drawings These ideas will have to be modified when you start to work out the actual coordinates to ensure that the surfaces really are plane Here are some ideas that may help you to create correct surface files faster e Exploit symmetry If the room has an axis of symmetry place the coordinate axis on it Then use the sign convention for symmetric semi symmetric modeling e f there are vertical walls and or features which repeat vertically e g identical balconies use the CountPt CountSurf RevSurf statements or indeed For End constructs e Build the room gradually testing the Par file at each stage of growth by loading it into ODEON and have a look at the result e Use hybrid statements such as Box Cylinder etc 3 42 Where it is difficult to ge
71. ach column in order to make surface and point numbers unique The different positions of the points used for each column are obtained using MTranslate and MReset Parametric sample BoxColumnRoom Par HHH const L 10 const W 4 const H 3 const NumColX 4 const NumColY 3 const ColumnW 0 3 mTranslate 1 2 0 0 Box I lw h tb walls in the room modeling the columns 3 45 for ColYCnt 1 NumColY MReset MTranslate L NumColX 1 w 2 Col Cnt W NumColY 1 0 for ColXCnt 1 NumColX NumbOffSet NumbOffSet 8 comment hint setting NumbOffSet to Auto would do the same job Box 1 ColumnW ColumnW h n columns in the room MTranslate L NumColX I 00 end end HH Using hybrid statements and coordinate manipulation The following example demonstrates an example on how to use the hybrid statements Cylinder2 and Dome2 as well as the coordinate manipulations which are essential to the use of the hybrid statements This example is a rather complex one so the main parts of the file is explained below Line 3 7 Defining constants Line 8 9 Inserting the cylindrical wall which needs a rotation of 90 around the Z axis Line 11 The foot points of the cylindrical wall which is temporarily stored in Plistd are stored in PlistO for later use definition of the floor Line 12 13 Inserting the dome shaped ceiling The Z rotation has already been set to 90 when the wall was created Line 14 18 Setting the coordinate manipulation for the ceiling and cr
72. ailable at the local toolbar as well as from the toolbar dropdown menu e Assign Material assigns the material selected in the material list to the surface s selected in the surface list e Assign Material for all surfaces assigns the material selected in the material list to all the surfaces in the room e Global Replacement replaces all appearances of the material assigned to the selected surface in the surface list with the material selected in the material list This is useful if you wish to replace all appearances of a material with another e g using two layers of plasterboard instead on one e Assigning Scattering coefficient is done a little different You simply select the field at the surface and enter the scattering coefficient using the keyboard e Assigning Transparency coefficients select field at the surface and enter the transparency coefficient directly using the keyboard e Assigning wall Type allowing calculation of Transmission through walls or fine tuning scattering diffraction algorithms e Repeat Scattering coefficient assigns the scattering coefficient last entered in the surface list to the current selected surface e Repeat Scattering coefficient for all surfaces assigns the scattering coefficient assigned to the surface selected in the surface list to all the surfaces e Quick Estimate for fast evaluation of reverberation times and listing of summarized absorption areas while assigning materials etc e Edit
73. al Estimate and Quick Estimate If the Scattering Method is set to Lambert all directions of late reflections are calculated using the scattering coefficients assigned to the surfaces in the Materials List E g if the scattering coefficient is 10 the new ray direction will be calculated as 90 specular and 10 scattered random direction due to a Lambert distribution If the Scattering method is set to None scattering is not taken into account thus all reflections are calculated as specular and if it is set to Full scatter 100 scattering is applied to all surfaces These settings are not recommended except for initial tests demonstration or research purposes Oblique Lambert The Oblique Lambert method allows including frequency dependent scattering in late reflections of point response calculations this option is recommended Reflection Based scatter The Reflection based scattering method automatically takes into account scattering occurring due to geometrical properties such as surface size path lengths and angle of incidence The use of the method is recommended unless that part of scattering has already been included in the scattering coefficients assigned to the rooms surfaces Interior margin Typical geometrical offsets in the boundary of the room default is 10 centimetres Surfaces which are closer to the boundary surfaces of the room than the distance specified by the Interior margin will also be considered bou
74. angle gt Revangle must be within the range 360 and different from zero If RevAngle is 180 a half cone is generated if its 360 a full cone is generated Positive revolution angles are defined counter clockwise lt Height gt The Height must be different from zero If the height is less than zero the orientation of the dome is inverted Height must be different from zero and less or equal to Width Connection points The right side vertical points in Dome2 are stored in PlistA The left side vertical points in Dome2 are stored in PlistB In the special case where the revolution angle is 180 all points are stored in Plistd and the number of vertical subdivisions is stored in ONVert The example shown was generated with the following code HHH Const N 16 Const W 10 Const H 3 Const L 10 Dome2 1 NW H 270 Dome calotte HH Hint The cylinder can be made elliptical using the MScale statement DebuglsOn and Debug The debug options are useful when creating large or complicated geometries in the Odeon par format Using these facilities can speed up geometry loading when loaded for preview only and allow debugging of parameter values in geometry files DebuglsOn is a Boolean which can be set to TRUE or FALSE the syntax is 3 41 DebuglsOn lt Boolean gt Typically you will insert the Debug sOn flag in the beginning of the geometry file in order to investigate parameter values when loading a geometry When this Boolean
75. as been closed the 3DView will display surfaces which is considered to be interior in a greenish colour while the exterior is displayed in black Diffraction from the exterior will be calculated taking into account that diffraction is limited towards the lowest frequencies because of limited depth of the wall constructions Limitations In special cases the Reflection Based Scattering Coefficient may overestimate the scattering provided by small surfaces which are only fractions of a bigger whole e g small surfaces being part of a curved wall or dome Such surfaces should not cause diffraction due to their individual area because the individual surfaces do not provide any significant edge diffraction In these cases the method can be bypassed by setting the surface Type to Fractional in the MaterialsList see chapter 4 When setting the Type to Fractional the surface area used for calculating the Reflection Based Scattering Coefficient is determined 6 78 from the box subscribing the room rather than the individual surface if the construction part which the fractional surface is part of is considerable smaller that the room box scattering might be underestimated and a higher scattering coefficient should be assigned to the surface Figure 6 A typical diffuser depth interior margin entered by user determines which parts of the geometry should be considered exterior of a room thus limiting the scattering of the boundary surfaces which can no
76. ast and easy to use binaural auralization is provided by the Steaming convolution facility to learn more about this facility use the online help from within the JobList If greater flexibility is needed a separate auralization display appears when using the toggle button Alt T from within the JobList Offline convolution for flexible Auralization In the left part of the auralization display mono signals are convolved with impulse responses in the right part of the auralization display such convolved signals may be mixed together in order to create multi channel simulations The Auralization results may be either two channel signals binaural which should be listened to through headphones or multi channel signals to be played through a surround system The mono input signal is selected in terms of a signal file and a channel in that file In a stereo signal file channel 1 is the left channel signal channel 2 is the right channel signal and average is the average signal of the channels included in the file A signal file is typically 1 channel mono or 2 channel stereo but may in principle contain many channels The impulse response is selected in the Job no column and refers to the Single Point Response with that job number Once the impulse response has been selected the point through which the receiver is oriented is displayed in the corresponding 3D display and the used receiver position is displayed in the table in the auralization
77. at rays do not even have to come near to the receiver to make a contribution Thus even in coupled room it is possible to obtain a reasonably number of reflections at a receiver which is required to obtain a result that is statistically reliable with only a modest number of rays This results in a fine balance between reliability of the calculation results and calculation time A complete histogram containing both early and late energy contributions is generated and used to derive Early Decay Time and Reverberation Time The other room acoustical parameters are calculated on basis of energy collected in time and angular intervals For surface and line sources a number of secondary sources are placed randomly on the surface of the source each emitting one ray and radiating a possible contribution to the receiver The rays emitted from these source types generate an independent secondary source each time they are reflected Compared to the calculation principle applied to the point sources one might say that only late energy contributions are collected for these source types or rather that calculations are based on a sort of ray tracing 6 4 The Late ray reflection method of ODEON The Late ray reflection method is applied for all rays used in Quick Estimate and Global Estimate For point response calculations rays send out from a line or a surface use the Late ray reflection method from the first reflection of a ray reflection order
78. athematical expression like Length Sin PI 4 where Length is a user defined constant or variable Mathematical expressions may not contain any SPACE or TAB tabulation characters To get a complete overview of the mathematical functions available please refer to appendix A Points A point is made up from an unique point number and its X Y and Z coordinates Use the Pr MPt and CountPt statements to define points Points can also be defined implicitly using one of the hybrid statements Surfaces A surface is made up from a unique number an optional descriptive text and a number of points connected to one another To define surfaces use the Surf MSurf CountSurf ElevSurf ElevSurf2 and RevSurf statements Surfaces may also be defined implicitly using the hybrid statements Hybrid statements Hybrid statements are Box Cylinder Cylinder2 Cone Dome Dome2 and ElevSurf The hybrid statements create the points and surfaces needed to model the specified shape The points and surfaces created must always have unique numbers 3 22 Coordinate manipulation functions A set of functions for coordinate manipulation and surfaces made up from coordinates is included This includes rotation around the various axes scaling and translation These functions are needed in order to insert shapes defined by the hybrid statements in the geometry with the correct position and orientation Comments and empty lines Lines containing comments and e
79. ay modeling has been made easier calculation principles has been enhanced and huge amount of new features has been added Project files The only project file from versions earlier than 3 0 being fully compatible is the surface file SUR The rest of the project files are no longer valid And even though the sur format is still valid it is not recommended to model rooms in this format The par format is a much more efficient format Directivity files refereed to as source types in ODEON 2 xx ODEON 3 0 and later version uses eight bands of frequency information Thus previous directivity files e g OMNI SOU are no longer valid You can translate your old directivity files into new eight band directivity files e g OMNI SO8 using the Tools Directivity patterns Translate 6 band into 8 band menu entry in the Odeon programme And more importantly the current version of Odeon supports the Common Loudspeaker Format see chapter 10 1 2 1 3 6 Upgrading from version 3 1 and earlier If upgrading from ODEON 3 1 or earlier versions of ODEON the guided tour in chapter 2 and chapter 3 on modeling is indeed recommended reading Stepping through these chapters will save much time later on in particular its is important to be familiar with the new geometry modeling language and or CAD import options before starting large modeling projects Upgrading from Odeon 4 5 and 6 to Odeon 7 and later If you are having problems loading a room
80. backs A When an A is appended after the M factor this tells that Minimize colouration effects diffuse field approach was not enabled so the HRTF were optimized for Anechoic conditions i e no reflections present If no A is found in this place in the name then Odeon has attempted to Minimize colouration effects The enhancements applied may give some colouration effects because some frequencies are amplified for individual directions When this option is checked Odeon will try to accomplish that colouration is kept at a minimum in a multi reflection environment that is the average frequency response for all directions in the set of HRTF s is kept neutral Sample rate The sample rate of the HRTF This sample rate should be the same as the sample rate of the signal files anechoic recordings to be used The supplied HRTF s are sampled at 44100 Hz Apass Ripple of octave band filters in dB Smaller is better 0 5 dB is probably sufficient Astop Maximum possible attenuation of octave bands To allow complete attenuation of all reflections of a 16 bit signal 96 dB dynamic range As should be 96 dB however due to auditory masking we are not able to hear such differences so 40 dB is probably sufficient Smaller Asop leads to shorter calculation time of the BRIRs Band overlap in percent Octave bands implemented using FIR filters are not completely rectangular it takes some frequency span before they attenuates completely An overlap
81. between the filters of 100 percent gives a smooth transition between the filters which is probably a more realistic representation of real world reflections than shorter overlaps At the same time long overlap gives shorter calculation time of the BRIRs If you should need to use filters with other filter parameters e g Ax being 96 dB you should create a filtered set of HRTF s with these parameters use the File Create filtered HRTF s option Then from within your room select the new filter bank from the Auralization Setup If you should need to import other HRTF s than the Kemar 32 these HRTF s are installed but does need to be imported or Subject_021Res10deg 41 Installed as well as imported you should create a text file following the same format as used in the files Unity ascii_hrtf Kemar ascii_hrtf and Subject_021Res10deg ascii_hrtf These files can be found in the HeadAndPhone EE and HeadAndPhone EC directories To import a set of HRTF s select the Tools Create filtered HRTF s option then select the specific 5 65 HRTF ASCII file e g C Odw HeadAndPhones EE Kemar ascii_hrtf finally specify miscellaneous parameters when the import dialog appears for help on these parameters please press F1 from within that dialog You may also desire to import a set of HRTF which has already been imported in order to specify an alternative filtering approach e g to enhance the HRTF s in different ways Headphone filters I
82. ble and invisible images Images S1 and 12 are surface generating it Figure 1 visible from R while S2 3 and 12 are not illustrates the concept of visible and hidden image sources If an image is found to be visible then a reflection is added to the reflectogram if another ray has not already detected it In this early part of the point response calculation rays are only used indirectly to detect Image sources that are likely to be valid From Odeon version 4 2 the Image sources are split into a specular contribution and a scattering tree which consists of secondary sources on the image source surfaces allowing a realistic calculation of early scattering The attenuation of a particular Image source is calculated taking the following into account Fa 6 72 Directivity factor of the primary source in the relevant direction of radiation Reflection coefficients of the walls involved in generating the image Air absorption due to the length of the reflection path Distance damping due to the distance travelled from the primary source to the receiver Scattering loss frequency dependent due to the scattered energy which is handled by a scattering tree Scattering may occur because of surface roughness as specified by the scattering coefficients in the materials list or due to limited surface dimensions or edge diffraction Early scattering In short each time Odeon detects an image source an inner loop of scat
83. bout the modeling language is to study the examples which are installed in the Odw rooms manual examples directory along with the Odeon program open the room s in Odeon then click the Open the Odeon Editor icon on the toolbar in order to study the room Components in the modeling format The basic function of the modeling format is to allow modeling of surfaces in room geometries The surfaces can be modeled point by point surface by surface however it is also possible to make use of symmetry and to create repeated features in a room such as columns using programmatically loops finally it is possible to use hybrid functions which creates points as well as surfaces in terms of shapes such as boxes cylinder and domes Constants variables and counters Constants and variables can be defined and used in the file format It is a good habit to use constants whenever a value is used more than a few times in a file this reduces typing errors and it also makes it easier to make general changes to a geometry such as changing the height of a room Mathematical expressions Mathematical expressions can be used to express any real or integer number in the file e g coordinates constants variables counters point numbers surface numbers etc If you use a value that is not an integer value to describe a point or surface number being is an integer then that value will be rounded to the nearest integer value You may describe coordinates using m
84. bugger Analysing the geometry for unacceptable surface overlap in the 3DGeometry Debugger Checking for missing surfaces in the room forming holes in the geometry The Unique edge s function available from the 3DView may help you shortcut E e Testing water tightness of the room tracing rays in the 3D Investigate Rays or 3D Billiard window 3 5 1 B amp lviewing the room in a 3DView The 3DView displaying your room once loaded into ODEON has a large number of facilities which can be useful when creating and verifying geometries for Odeon aa AEETI al zj Figure 1 Viewing corners and coordinates in a selected surface using the N shortcut and highlighting corner and displaying the coordinates of the corner closest to the mouse pointer using the m shortcut The perspective option shortcut P allows you to turn off the perspective of the room to get an isometric display of the room This may prove valuable when investigating warped surfaces The Unique edge s option in the 3DView display shows edges which only occur on one surface Such an edge is free it might be the edge of a free hanging reflector but it could be the result of an error whereby two surfaces which should join along an edge do not 3 57 aia Example Modeling a box shaped room consisting of 6 surfaces but forgetting to define the 6 surface l in the geometry file This room will have a hole Bs where the 6 surface is m
85. capabilities and limitations of the program Chapter 7 describes the calculated point response parameters available in ODEON how they are calculated and how to interpret the results Chapter 8 describes the various calculation parameters available in the program Most of the parameters are automatically set to reasonable values by ODEON however for special cases you may find adjustment of some of the calculation parameters to be useful Chapter 9 is the discussion on quality of results and how to achieve good results This chapter may be relevant once familiar with the program Chapter 10 describes how to extend the library of directivity patterns available for point sources and the use of directivity patterns in the Common Loudspeaker Format CLF Happy modeling Claus Lynge Lyngby April 2007 vi Introductio Mss ecn ete ks Sc ce E ve ake we ec ee eee v MN OX PEE E T beeen cnn A E E TAT vii 1 Installation and running the program ssssssssssssrrsssrsrrrrssrrrrntnrrrrnnnnrrrrnnnnrrnnnnnnnnnnnnnnrnnn nrnna 1 1 1 1 Installing and running the program sssssssssssssrsrrrrssrrrnnnsrrrrnnnnrrrnnnnrrrnnnnnrrrnnnnurnnnnnnnnnn 1 1 T 2 Troubleshooting irnn E ee ed E E 1 2 1 3 Upgrading from previous versions ssssssssrssssssrrrrsrrrrrtnsrrrrntnnrrrnnnntnnnnnnnrrnnnnnnnnnnnnnnnnn 1 2 1 3 1 Upgrading to version 9 0 scciricidicspidid ngisin airaa R ra 1 2 1 3 2 Upgrading from versions earlier than version 8 9 sss
86. cece eee rene need 10 94 Common loudspeaker format CL1 and CF2 files ccc cece cece eee eeeeeeeee cease seaeeeeaeeeeaeeeas 10 94 10 1 File location for directivity files remeare cece cere eee eee eee eee ene sees eee dae R nan aei 10 94 10 2 Creating new directivity patterns in the Odeon S08 format eseeeeeeeee eee eee ees 10 94 10 3 Entering a directivity plot using the Directivity plot editor c cece eceeee eee eeee eee eeae ees 10 94 10 4 Creating a new directivity pattern using a text file AS INPUt cece eee eee eeeeeeeeeeeeaees 10 95 10 5 Compatibility with previous versions Of ODEON ccccceceeeeeeee eset eeeeee eset eens eeeeeneees 10 97 9 3 Making a readable text file from a directivity pattern file SO8 ccccceeeeeseeeeeeeeeaeeeas 10 97 Appendix A Mathematical expressions available in the Par modeling format eeeeeee teeta 98 Appendix B References a ecchar ted iee sd op ae pep eee ded tec nae hed a a a ina eed ees 99 Append C VoGabulary ceca cicvetieattaneta vals ca bbwida wal cide oath estds wale a eek vata SAMA salt ba lbua e buatea calbb ead sa Gb vaca EE 102 Appendix D Specify Transmission through walls ccccceceeeee eee eee eee cnet eee e eens eae eeee eee eae eeneenneeanes 104 viii 1 Installation and running the program 1 1 Installing and running the program ODEON comes on a CD ROM containing the three different editions of Ode
87. ces for a further discussion on parameters and design criterions Auditorium acoustics as Concert Halls Opera Halls Multipurpose halls etc are dealt with in 26 and 27 where different halls around the world are presented along with judgement of their acoustics and guidelines for design Short guidelines on which values to expect for Clarity and G in concert halls based on some simple design parameters as width height floor slope etc are given in 28 Some recommended values for room acoustical parameters Objectiv parameter Symbol Recommended Subj limen symphonic music Reverberation time T30 1 7 2 3 seconds 5 Clarity Cso 1 to 3 dB 5 Level rel 10 m free field G gt 3dB 1 dB Early Lateral Energy LFso gt 0 25 5 Fraction Early Support STearly gt 13 dB Total Support STiotal gt 12 dB Recommended values for ISO 3382 1 objective room acoustical parameters 6 in large music rooms with audience according to Gade 24 Subjective limen as given by Bork 39 and Bradley 40 Early Decay Time and Reverberation time The energies of all the reflections received at the receiver point are collected in histograms with class interval specified in the Room setup Impulse response resolution After completion of the response calculation early decay time and the reverberation time are calculated according to ISO 3382 6 The Reverberation time Tso is calculated from the
88. culating BRIR s left signal right signal and the stereo signal The stereo setup has now been completed and you may start calculations Run All Depending on the source gains you have chosen you may experience overload or under range in this case you should adjust the Recording Level Rcd Lev and or Mixer level and recalculate These levels correspond to the levels on a tape recorder and on a mixer and the problems concerning overload and under range are the same If levels are too low you will get a poor dynamic range and if too high you will experience clipping The Out Lev in the rightmost columns of the tables should not exceed O dB on the other hand if the output level is say 30 to 50 dB a very poor dynamic range is obtained 4 Playing results When calculations have finished you may play the calculated binaural simulations Select the relevant table row and column then click the play button or the Alt S short cut e To play the input signal select the Signal file column in the Convolve BRIR and Signal file table e To play the mono signals convolved with a BRIR select any other column in the Convolve BRIR and Signal file table e To play the mixed results select the relevant row in the mix table e Finally to play the individual components in a selected mix select the relevant row in the rightmost table mixer level adjustments are not taken into account These signals are just a repetition of the convolved results from the le
89. d then more rays should be used More rays needed There are no way of telling if more rays are needed for a certain calculation but to get an idea whether a room has strong decoupling effects you may try to run the Global Estimate calculation If e Global Estimate stabilizes slowly e The Global decay curve make sudden jumps like steps on a stair e The Global decay show hanging curve effect This could be an indication that more rays are needed Let the Global Estimate run until the decay curve seems stable then use say 1 10 1 times the number of rays used in the Global estimate to specify the number of rays to be used in the calculation of the point responses specified in the room setup Transition order The Transition order can be optimised taking into account the basic properties such as room shape into account se section 8 for suggestions on Transition order 9 91 9 1 3 Materials absorption data Wrong or imprecise absorption data are probably one of the most common sources of error in room acoustical simulations This may be due to lack of precession in the measurements of the absorption data or because the material construction assumed in the simulations are really based on guesswork in any case it is a good idea to remember this and to estimate the size of error on the material data as well as the impact on the simulated results Solution if materials data are uncertain There is really not much to do
90. d if you wish to model in a unit different from metres The unit used in the parametric file is by default assumed to be metres however if you prefer to model in another unit this is possible using the Unit statement Check the example below Example modeling in Inches Unit Inches You may choose your unit among the following predefined Metres Centimetres Millimetres Inches Feets and Yards Or if you need a different unit simply type the scaling factor from your unit into metres e g Unit Inches corresponds to Unit 0 0254 The Unit statement may be used more than once in the same par file HHH Unit Inches je g imported model data in inches aise model data Unit 0 57634 model data measured on a paper drawing which appeared in an odd unit sete model data eee model data Unit Metres s model data appended in the Odeon editor modeling environment sit is most paratical to use metres as the unit when modeling in the Odeon environment then coordinate values will be the same in the Editor as inside the 3DView in Odeon Hit 3 32 CoordSys statement The CoordSys statement is used if you wish the redefine the orientation or the coordinate system in which the geometry was modeled The statement is typically used if the geometry was by accident modeled in an orientation different from the one assumed by ODEON or if it was imported from a CAD drawing where the orientation may also be different
91. del using the Ctrl Arrow shortcut See the corresponding 3DOpenGL dropdown menu for more shortcuts When materials have not been assigned to all surfaces in the room surfaces will appear in random colours making holes easier to spot If materials have been assigned the colours will by default reflect the acoustic properties of the surfaces however it is possible to turn on the random colouring at will using the R shortcut Do note That 3DOpenGL may occasionally fail to display complicated surfaces including numerous holes correctly typically surfaces created by CAD software using solid modeling techniques and substractions although the surfaces are perfectly legal with respect to ODEON In these rare cases you may assure yourself that the model is in fact correct by putting point sources at various test positions and conduct tests using the 3D Investigate Rays and 3D Billiard utilities 3 6 1 a 3DGeometry debugger Overlapping and warped surfaces should be avoided in the room model specified in the geometry file but a certain amount of overlap and warp by default 50 mm is allowed without generating a warning By overlapping surfaces is meant surfaces which define a part of the same plane in space In the 3 58 simple case this can be because the surfaces are simply duplicates another case could be a door which has been defined in the same plane as the wall in which it is mounted Overlapping surfaces should be avoided because it will n
92. deon Room Acoustics Program Version 2 5 User Manual Publication No 49 The Acoustics Laboratory Technical University of Denmark Lyngby 1994 103 pages 9 J H Rindel Computer Simulation Techniques for Acoustical Design of Rooms Acoustics Australia 1995 Vol 23 p 81 86 10 J H Rindel Computer simulation techniques for the acoustical design of rooms how to treat reflections in sound field simulation ASVA 97 Tokyo 2 4 April 1997 Proceedings p 201 208 11 Cremer L and H M ller Principles and Applications of Room Acoustics Applied Science Publishers London 1982 12 Barron M and A H Marshall Spatial Impression Due to Early Lateral Reflections in Concert Halls The Derivation of a Physical Measure Journal of Sound and Vib 77 pp 211 232 1981 13 Kristensen J Sound Absorption Coefficients Measurement evaluation application Note no 45 Statens Byggeforskningsinstitut H rsholm 1984 in Danish 14 Knudsen V O and C M Harris Acoustical Designing in Architecture John Wiley 1953 15 Bobran H W Handbuch der Bauphysik Verlag Ulstein Berlin 1973 16 Ingerslev F L rebog i bygningsakustik for Ingenigrer Teknisk forlag Copenhagen 1949 17 Petersen J Rumakustik SBl anvisning 137 Statens Byggeforskningsinstitut H rsholm 1983 18 Parkin P H H R Humphreys and J R Cowell Acoustics Noise and Buildings Faber and Faber London 1979 19 Fas
93. der statement defines a cylinder shell with or without top and bottom The statement may typically be used for modeling cylindrical room or columns The Cylinder2 statement which creates a cylinder of the calotte type will usually be preferable for modeling cylindrical ceilings The syntax for Cylinder is Cylinder lt Number gt lt NumberOfSurfaces gt lt Radius gt lt RevAngle gt lt Length gt lt T B N gt lt optional name gt lt Number gt A unique number from 1 to 2 147 483647 for identification of the first point and surface in the Cylinder Using the same number but with negative sign defines the cylinder and its mirrored counterpart in the XZ pane Y 0 A Cylinder will take up several point and surface numbers which must all be unique lt NumberOfSurfaces gt For a full cylindrical room with a revolution angle of 360 around 16 to 24 surfaces are recommended For columns a number between 6 to 8 is recommended lt Radisus gt Radius of the cylinder must always be greater than zero lt Revangle gt Revangle must be within the range 360 and different from zero If RevAngle is 180 a half cylinder is generated if its 360 a full cylinder is generated Positive revolution angles are defined counter clockwise lt Height gt If the height is less than zero the orientation of the cylinder is inverted If height equals is zero one circular surface is generated Insertion point The insertion point of
94. des the room breaking up long reflection paths and introducing extra absorption and scattering should neither be omitted Furniture at more distant locations in the room which does not produce any strong early reflections to the receiver can be greatly simplified or even omitted from the model as long as the a extra absorption and scattering produced by that furniture is somehow included on other surfaces in the same regions of the room How to model a table with chairs An easy way to model a table with chairs around it is to model a box making its side surfaces semi transparent by setting the transparency coefficients to values greater than zero e g 0 5 in the Materials list inside Odeon If the furniture is basically plane surfaces then low scattering coefficients should be assigned just like for any other type of plane surface provided that Reflection Based Scatter is activated Only if major details e g computers and computer screens are omitted in the model should the scattering coefficients be increased to e g 0 5 It may be acceptable to model the geometry in more detail but the above method seems to work well and makes the modeling process faster Orientation of surfaces does tilt of a surface have any significance on room acoustics Small changes to the orientation of surfaces can indeed cause dramatic changes Making dominant surfaces slightly off angle can cause extra scattering in the room almost as if extra scatteri
95. display The recording level may have to be adjusted in order to get a good dynamic range or on the other hand to avoid overload The output level achieved when convolution has been carried out is displayed in the rightmost column and should never exceed O dB The recording level corresponds to the recording level on a tape recorder If you wish to compare different simulations you should use the same recording level Creating multi channel auralization is by nature a little complicated and you should get familiar with one channel simulations before using this feature the mixer Multi channel simulations can be created using the mixer in the auralization display the two rightmost tables The mixer allows you to mix together up to 25 one channel simulations from the Convolve BRIR and Signal file table The simulations can only be mixed together if they e use the same receiver position Point Response Receiver e use the same orientation receiver towards source To check this scroll through the Convolve BRIR and Signal file table and view the receiver column Rec and the receiver towards source point which is displayed as a red cross in the corresponding 3D display Other facilities in ODEON Apart from the features demonstrated in the above tour ODEON also contains facilities for Calculation of transmission through walls this issue is covered in Appendix D Copying the project files generated by ODEON available from the Files me
96. dividual loudspeakers to the receivers if the Compensate speaker delays option is checked and in order to compensate for difference between the angles which are covered by each two loudspeakers if the Parameterization option is checked Even though Odeon performs these compensations it is recommended to use a speaker layout with as equal angles between the speakers as possible and if possible with left right symmetry Check that labels displayed in the map of loudspeakers is in agreement with the loudspeaker coordinates entered then if this is the case close the Define speaker rig dialog The Auralization setup dialog is still open and it may be a good idea to save the defined speaker rig just defined to a seperate archive file it may be needed at a later point e g if moving Odeon to another computer upgrading the program etc 5 The Out lev displays the level of the sample having the highest value in the resultant wave file this value should not be confused with loudness or RMS 2 11 A note on mapped speaker rigs Surround sound files can be mapped by ODEON if this option has been selected in the Define speaker rig dialog An example of a mapped file may be a 5 1 surround file which contains 6 channels that should be feed into front left right left back right back and subwoofer channels If loudspeaker system surround soundcard and its setup match this then the signals will automatically end at the right places In order t
97. e Once sent from a source rays are followed around the room as they become reflected and the geometrical data is stored id numbers of walls hit points of incidence etc The criterion for stopping the trace of a given ray is normally a geometric one either the path length travelled set by the Impulse Response Length or number of reflections experienced Max reflection order The geometrical data produced is written continuously to the hard disk and used later in the determination of reflections received at a point The early reflections of rays from points sources are treated a little bit different from the rest of the rays because they are reflected speculary if the reflection order is less or equal to the Transition order allowing the detection of image sources Above this order the rays are reflected due to the Late ray see section 6 4 method of ODEON Single Point Multi Point and Grid Response the receiver dependent part Having traced rays around the room and stored the data of ray histories the next step is to place the receiver at a specific point and so to speak collect the reflections there These point response calculations are the receiver dependent part of the calculations at this point the contributions of direct and reflected sound are collected at the receiving point allowing the calculation of the results known as Single Point Multi Point and Grid Response When more than one receiver is involved the rece
98. e containing 5 sub surfaces MSurf 1 5 Steps on a stair 5544 gt 5534 5112 gt 5122 5111 gt 5101 5212 gt 5222 5211 gt 5201 5312 gt 5322 5311 gt 5301 5412 gt 5422 5411 gt 5401 5512 gt 5522 Elevation surface Use The ElevSurf statement to define a series of vertical surfaces from a series of perimeter points plus an elevation height The perimeter points are typically defined using the MPt statement The syntax of ElevSurf is ElevSurf FirstSurfaceNumber gt lt FirstPointNumber gt lt SectionsInElevSurf gt lt Height gt lt Optional name gt Example on use of the MPt and ElevSurf statements First the perimeter points point 1 to 23 at the floor level of an office environment are described using the MPt statement Then the elevation surface is created from these points creating the perimeter walls of the office with a constant height of 2 7 metres Finally the floor and ceiling is created using the Surf statement 0 00 10 00 20 00 30 00 40 00 metres Perimeter points at the floor level Example file MPt and ElevSurf Par Demonstrates the use of MPr multi point Surf Surface and ElevSurf Elevation surface statements In this example the X coordinates are made in absolute values whereas the Y coordinates in most cases are in or de creased using the or options To create a closed ElevSurf that is the first wall joins the last wall first and last point in the series of points handled to the ElevSurf must be identical in
99. e direct sound The minimum source receiver distance according to ISO 3382 is 9 92 d nin T 2 c T where V is the volume of the room in cubic metres c is the speed of sound in metres per second T is an estimate of the expected reverberation time in seconds Thus for a typical concert hall a source receiver distance less than 10 metres should be avoided in order to get good predictions measurements of the reverberation time 9 1 8 Minimum distance from the receiver to the closest surface If a receiver is place very close to a surface then results will be sensitive to the actual position of the secondary sources generated by ODEON If such a secondary source happens to be very close to the receiver e g 1 to 10 centimetres this may produce a spurious spike on the decay curve resulting in unreliable predictions of the reverberation time indeed if the distance is zero then in principle a contribution being infinitely large would be generated To avoid this problem is recommended that distances to surfaces are kept greater than say 0 3 to 0 5 metres Anyway for measurements it is for other reasons recommended to keep distances greater than a quarter of a wavelength i e 1 3 metres at 63 Hz a distance of 1 metre is required by ISO 3382 9 93 10 Directivity patterns for point sources Common loudspeaker format CL1 and CF2 files Odeon 8 and later supports the Common Loudspeaker Format which is an open format for loudspeak
100. e energy form one of its two sides or from both its sides Finally set the Overall gain to 65 dB To save the new source just close the Multi surface source Editor and confirm Surface source The facilities of the surface source are fully included in the multi surface source the surface source is only available for compatibility reasons Bhetine receivers Click the New receiver button to open the Receiver editor Enter the values x 1 5 metres y 0 5 metres and z 1 65 metres To save the new source just close the Receiver Editor and confirm Define other receivers at x y z 12 3 2 2 x y Z 8 7 1 5 x y Z 21 1 3 6 We will get back to the receivers and the activated sources under the point Calculating Point Responses Assign material properties Open the Materials List and see how to operate in the Materials menu Assign the following material data to the surfaces in the model Surface 1001 1002 2001 2002 2003 2004 3001 3002 number 2002 2003 Material 901 905 702 702 702 702 702 702 Scatter 0 7 0 7 0 05 0 05 0 05 0 7 0 05 0 05 Hit the F1 shortcut to learn more about scattering coefficients and other material specifications Notice high scattering coefficients are used on the floor and sidewalls in order to model machinery and beams EJ Quick Estimate fast estimation of Reverberation Time From within the Materials list run the Quick Estima
101. eating the ceiling Line 19 Resetting the coordinate manipulation to work in absolute coordinates Line 20 23 Creating Wall floor point Line 24 25 Defining floor using the cylinder points stored in Plist0 Line 28 29 Defining side walls using symmetric modeling Line 30 31 Defining back wall using the ceiling cylinder points which is still stored in PListB Dome2 and cylingder2 x 2 room par Ht const H 5 Const L 10 Const W 15 Const N 12 Const HCurve 4 NAMARWND MRotateZ 90 Cylinder 1000 N W 2 180 H N 10 Storres PListA for later use with floor 11 PList0 PListA 9 12 MTranslate 0 0 H 13 Dome2 2000 N W HCurve 180 Halfdome 14 MReset 15 MRotateZ 90 16 MRotateY 90 17 MTranslate 00 H 18 Cylinder2 3000 ONVert W HCurve L n Cylindric ceiling 19 MReset 20 Pt1 0W 20 21 Pt2 LW 20 22 Pt3 0 W2H 23 Pt4 LW2 H 24 Surf 1 Floor 25 2 PlList0 2 26 done with PList0 its a good habit to Reset it 27 ResetPList0 28 Surf 2 Side Walls 29 1243 30 Surf 3 BackWall 3 46 2 PlListB 2 31 Ht Defining surfaces with concave edges Most surfaces in the geometries used with ODEON will probably be have convex edges rectangles cylindrical surfaces etc however in ODEON it is possible to define surfaces with cavities even surfaces with holes Such surfaces are defined just like any other surface by creating a list of corners where the listing is obtained by travelling around the
102. ed x y and z scale The default setting is Scale 1 1 1 The Scale command evokes scaling of coordinates after all other coordinate manipulation is carried out If you should need more advanced scaling options please use the MScale option Coordinate manipulations the M family Advanced coordinate manipulation can be carried out using matrix manipulation The coordinate manipulation functions which is essential to the use of hybrid statements Box Cylinder etc is implemented as the following functions MTranslate lt TranslateX gt lt TranslateY gt lt TranslateZ gt MRotateX lt Rotation angle gt MRotateY lt Rotation angle gt MRotateZ lt Rotation angle gt MScale lt ScaleX gt lt ScaleY gt lt ScaleZ gt MPop MReset The manipulations carried out by the M family are cumulative This means that you can specify more than one operation to be carried out e g first rotate 90 around the Z axis then rotate 90 around the Y axis and finally translate 10 metres upwards The following example shows these operations carried out on a cylinder shell the Cylinder statement is described later Manipulating a cylinder Par HHH MRotateZ 90 MRotateY 90 MTranslate 0 0 10 Cylinder 1 20 5 180 10 TB Cylindrical ceiling HE The transformation commands to be carried out must always be stated before the points geometry on which they should work is created To reset all previous coordinate manipulations use the MReset command
103. ed on either or both reference coordinates of existing points The snap point The snap point is a special case of snap to existing points In some cases you may want to move a surface to a precise location e g 0 33 0 46 not being a point on the grid nor an existing point of another surface In that case e Create a new surface Click the approximate position of the reference point Change the coordinates to the exact position e g 0 33 0 46 in the Point editor Press Insert or Esc to finish editing the surface the point will appear with the mark Snap point Select the fix point in the surface to be moved left mouse button and move it to the location of the snap point Do note that Snap to existing coordinates option must be checked Once the surface has been moved the surface containing the snap point may be deleted this is not a strict requirement as surfaces containing only one point will not be transferred to the par format to be used in Odeon Relative or absolute extrusions Use the Ctrl H shortcut to toggle between relative or absolute extrusions in the Surface editor table When extrusions are displayed in relative measures an extrusion may be defined as Z 10 and dZ 5 telling that the extrusion starts at a height of 10 and has an extrusion height of 5 If toggling to absolute extrusion then the same extrusion is displayed as Z1 10 and Z2 15 telling that it starts at Z 10 and ends at Z 15 Modeling an array of surfaces has
104. ed to that surface inside the Odeon program The Auto option is very useful in combination with loop constructions see description of the for end constructs later on Typing PrtAbsRef after the value assigned to NumbOffSet forces absolute number references for points while using the specified offset on the numbers of surfaces this is explained later 3 24 Example on the use of NumbOffSet creating surface 101 containing the points 101 to 104 and surface 201 containing the points 201 to 204 NumbOffSet Par Ht NumbOffSet 100 Pt 1 0 1 0 Pt 2 0 1 0 Pt 3 1 1 0 Pt 4 1 1 0 Surf 1 A surface 1 2 3 4 NumbOffSet NumbOffSet 100 Y Pt 1 0 1 1 Pt 2 0 1 1 Pt 3 1 1 1 Pt 4 1 1 1 Surf 1 Another surface 1 2 3 4 HE Example creating point 1 4 and surface 1 setting NumbOffSet to Auto then creating Point 5 8 and surface 5 Hitt Pt 1 0 1 0 Pt 2 0 1 0 Pt 3 1 1 0 Pt 4 1 1 0 Surf 1 A surface 1 2 3 4 NumbOffSet Auto Pt 1 0 1 1 Pt 2 0 1 1 Pt 3 1 1 1 Pt 4 1 1 1 Surf 1 Another surface 1 2 3 4 HT Defining a point using the Pt statement Use the Pr statement to define a single point The syntax must be as follows Pt lt Point Number gt lt XMathExpression gt lt Y Math Expression gt lt ZMathExpression gt Example defining point number 100 in x y z 1 1 1 Pt 100 1 1 1 Hint Point number and coordinates can be written using mathematical expressions allowing greater flexibility and reusability Parametric modeling d
105. efining multiple points Use the MPt statement to define a series of points which is typically used in connection with the ElevSurf or ElevSurf2 Statement The syntax must be as follows MPt lt Number gt lt NumberOfPoints gt lt XMathExpression1 gt lt YMathExpression1 gt lt ZMathExpression1 gt lt XMathExpression2 gt lt YMathExpression2 gt lt ZMathExpression2 gt VumberOfPoints lines each defining a point in the multi point sequence should follow the MPt statement lt Number gt 3 25 A unique number from 1 to 2 147 483647 for identification of the first point in that multi point sequence lt NumberOfPoints gt The number of points defined by this multipoint statement if the number is 3 then 3 lines should follow each describing the coordinates of a point Example 1 defining point number 100 in x y z 1 1 1 and point number 101 in x y z 2 2 2 MPt 1002 10 1 0 1 0 2 0 2 0 2 0 As a special option for multi points it is possible to repeat a coordinate used in the previous point of that multipoint sequence or to repeat the coordinate while adding or subtracting a value from that point Example 2 defining point number 100 in x y z 1 1 1 and point number 101 in x y z 1 2 0 MPt 1002 1 1 1 Defining a series of points using the CountPt statement The CountPt statement must follow the syntax CountPt lt FirstPointNo gt lt MaxCount gt lt XMathExpression gt lt YMathExpression gt l
106. ences HRRF s are not used in this calculation which is aimed at loudspeaker representation where the listener will receive reflections from own head and torso The other difference is that reflections are added with random phase 6 9 Calculation method for Reflector Coverage 25000 rays are send out from the selected source if the rays hit one of the surfaces defined as reflector surfaces at the Define reflector surfaces menu a cross is painted where the reflected rays hits the 6 81 room surfaces Note that the value of the Transition order is taken into account if it is zero and the Lambert scattering is active the chosen reflectors will exhibit a degree of scattered reflection corresponding to their scattering coefficients Sound from line and surface sources will always reflect scattered if the Lambert scattering is on 6 82 7 Calculated Room Acoustical parameters This chapter will shortly describe the derivation of energy parameters for Single Point Multi Point and Grid response calculations for the Industrial edition only EDT T30 SPL SPLa and STI are available All the parameters are derived on the assumption that the addition of energy contributions from different reflections in a response is valid This manual will not cover the use of the individual parameters in depth and suggestions on ideal parameters choice should only be sought of as a first offer instead refer to relevant literature e g some of the following referen
107. eometry once it has been imported The 3DView display which displays the geometry one it has been imported is a useful tool for this purpose please see the context sensitive help available in this display from within Odeon for further details shortcut F1 Example Importing the supplied ElmiaDXFSample dxf and changing its Origo Try importing this dxf file which is located in the room directory To make the operation of Odeon as smooth as possible it is desirable to move the Origo of this geometry Once the geometry has been imported this change may be made as follows Investigate the coordinates of the front edge of the stage 1 Turn on the modeling options in the 3DView shortcut M on and move the mouse in order to investigate the corners coordinates 2 If pressing the Ctrl key while Left clicking the mouse then the data for the closest corner is copied to the clipboard the data text can be pasted into the Odeon s editor using the Ctrl V shortcut Pasted corner data from the 3DView Pt 248 10 500 5 90000 24 00000 for a left point on the stage Pt 247 10 500 5 90000 24 00000 for a right point on the stage We may want to locate Origo at the front of the stage This can be done using the Mtranslate statement in the geometry file in order to move the mid point average of the two points above of the stage to 0 0 0 open the par file clicking the Odeon editor icon then just after the sign type MTrans
108. er data supported by several loudspeaker manufacturers as well as manufactures of software programs such as Odeon The Common Loudspeaker Format was developed and is maintained by the CLF group at www clfgroup org It is an open though secure file format for loudspeaker performance data and polar plots which loudspeaker manufacturers can use to supply data to end users in the professional sound and acoustics community CLF is defined in two parts a text based format used solely for data input and editing and a binary format for data distribution as a user of ODEON you should deal only with the binary distribution files having the extensions CL7 and CL2 In order to view all data in the CLF format you should download a free viewer from the CLF home page The CLF Group is providing a set of free tools for data editing conversion from text to binary format and viewing binary data allowing loudspeaker manufacturers to create view and verify binary distribution files for use in programs such as Odeon This ensures that it is easy for loudspeaker manufactures to make these data available Links to loudspeaker manufacturers currently providing binary distribution files can be found at the download page at www clfgroup org If apparently the data of interest is not available from the manufacturer of interest then assist the Clf group by encouraging the manufacturer to make such data available free tools for this purpose can be obtained at www clfgroup
109. erfect within one subjective limen Sometimes this is quite acceptable because we are just interested in rough results at other times we are interested in results as good as possible In any case being aware of the sources of error may help getting the maximum out of ODEON The sources of error or at least some of them are The approximations made in the ODEON calculation algorithms Inappropriate calculation parameters Material absorption coefficients are imprecise Material scattering coefficients are imprecise 9 90 e Geometry definition may not be accurate e The measured reference data to which simulations are compared may not be accurate 9 1 1 Approximations made by ODEON It should be kept in mind that algorithms used by a program such as ODEON are but only a raw representation of the real world In particular the effect of wave phenomena are only to a very little extend included in the calculations There is very little to do with this fact for you the user except to remember that small rooms and rooms with small surfaces are not simulated at high precision 9 1 2 Optimum calculation parameters A number of calculation parameters can be specified in ODEON These setting may reflect reverberation time a particular shape of the room or a trade of between calculation speed and accuracy Decimate late rays To use all the reflections found in the ray tracing process the Decimate late rays option should be switched off and the La
110. ert a rotation point in the surface b Use the Rotate surface shortcut Ctrl R to activate the rotation dialog and specify the rotation angle in this case 25 degrees finally delete the rotation point from the surface Examles A few examples on extrusion models are installed with Odeon the examples are located in the odeon rooms oes Directory The best way to learn about benefits as well as limitations of the extrusion modeler may be to load the examples investigate the surfaces e g scrolling the point and surface tables and to load the models into Odeon in order to investigate the models when they become extruded Special extrusions There are a few extrusion surfaces which are treated differently by the extrusion modeler 1 A surface with an extrusion height of zero will produce one and only one horizontal surface no matter if a bottom or top surface is selected 2 An extrusion surface which only contains two points will only produce one vertical surface neither bottom or top surface is produced only a single extruded surface if the extrusion height of this surface is zero then no surface is produced an exception to the exception 3 52 3 4 Importing DXF files The support for the DXF file format Drawing eXchange Format allows import of CAD models exported from modeling programs such as CAD package Web addresses Demo available for download IntelliCAD http www autodsys
111. es in the MaterialsList e Same set of reduction indexes are selected on either surface in the Transmission dialog e Double sided wall check mark is selected for both surfaces in the Transmission dialog Most of the above can usually be accomplished if the Update double sided wall upon exit is checked when Transmission data for the first wall is edited It is recommended checking and rechecking the data entered for transmission data before making calculations a check may involve using the 3DBilliard or 3D Investigate Rays to ensure that walls do in fact transmit sound and that double sided walls has been set up correctly 104 l 0 00 l 2 00 l 4 00 l 6 00 l 8 00 l 10 00 metres 6 00 metres N J i P1 0 00 7 Path lt m gt 7 20 Refl Time lt ms gt 21 Dead balls 0 Odeon 1985 2007 Figur D2 3DBilliard display illustrating Transmission through a double sided wall as can be seen ODEON understands correctly that balls should jump through the wall from one surface to another The principle of calculations is shown in figure D2 Statistically 50 of the ball rays are transmitted and 50 are reflected However this is compensated for in the calculations so the energy loses in the two rooms are determined by the absorption coefficients and reduction indexes as used Odeon 1985 2007 Figur D3 The Transmission Rooms par sample is installed with Odeon The figure illustrates how transmission data
112. es not produce an exponential growing number of reflections with respect to the time as would be expected in the real room but keeps the same reflection density in all of the calculation in order to keep down calculation times The attenuation of a secondary source is calculated taking the following into account Directivity factor of the primary source in the relevant direction of radiation point sources only Reflection coefficients of the walls involved in generating the image Air absorption due to the length of the reflection path Distance damping due to the distance travelled from the primary source to the receiver is inherently included in the ray tracing process e Directivity factor for secondary sources e g the Lambert Oblique Lambert or Uniform directivity see later 6 73 Summarising the calculation method used for point response calculations in ODEON As described above the point response calculation in ODEON is divided into a receiver independent and a receiver dependent calculation part The division into two calculations is solely done in order to save calculation time by reusing parts of the calculation where possible S Energy Time Figur 2 Summary of the model for response calculations Inset shows resulting reflection sequence at receiver R Looking at the calculation as a whole only with respect to one receiver may help understanding the concept In figure 2 reflections generated by a poi
113. escribed in more detail in 24 Early Support or ST1 E ST os 20 100 dB early _ E 0 10 Late Support ST Mes E 00 1000 dB late Eo10 Total Support ST E 0 1000 dB total Eo 0 STearly or ST1 is used as a descriptor of ensemble conditions i e the ease of hearing other members in an orchestra STiate describes the impression of reverberance and STtota describes the support from the room to the musicians own instrument If the early late averaging is turned ON averaging in time is performed as for the other parameters In case of the stage parameters the following limits of time intervals are used 9 ms 10 ms 11 ms 18 ms 20 ms 22 ms 900 ms 1000 ms and 1100 ms Warnings displayed with the room acoustical parameters When the calculated reverberation curves appears very uneven ODEON may come up with the following warning Warning Direct sound not found C D LF may not be reliable When ODEON calculates the parameters including time intervals in the parameter definition e g the Cso parameter the origin of the time axis are set due to the closest source from where direct sound is 7 85 received If no source is visible from the receiver or if a hidden source acts significantly earlier at the receiver the time origin may come somewhat after the beginning of the actual reflectogram sequence The warning may of course also indicate an erroneous position of the receiver STI Speech Transmission Index
114. essions lt Optional Description gt A string displayed and printed for easy identification of the surface Could be something like Main floor lt ListOfPointNumbers gt Each surface may be bounded by between 3 and 500 corners which all lie in a plane Corner numbers refer to the corners which must have been defined e g using the Pr or CountPt statements before using the surface statement The order of listing must be as obtained by travelling around the surface s 3 26 edge in either direction The list of corners must be on the same line A room may contain up to 10000 surfaces Example 1 surface made from point 1 2 3 4 Surf 100 floor 1 2 3 4 Example 2 surface made from point 1 2 10 11 12 13 14 4 5 Surf 200 Ceiling 1 2 10 gt 14 4 5 If there is a need to programmatically build a list of points this can be done using the PList and ResetPList statements Building lists of points using PList and ResetPList The PList and ResetPList statements are used in special cases together with the Surf statement Twelve lists are predefined namely PList0 to PList9 and PlistA and PListB which are handled automatically by ODEON The PList statements allows to programmatically construct a list of points e g a list like 100 110 120 130 140 150 160 170 180 190 200 this can be done using a for end construct in the following way adding a point number at a time for MyCounter 0 10 PList0 100 MyCounter 10 end It is also
115. f 50 results in a reflected direction which is the geometrical average of the specular direction and a random scattered direction Note Scattering is a 3D phenomena but here shown in 2D 6 5 The Reflection Based Scattering coefficient When the reflection based scattering coefficient is activated in the room setup ODEON will do its best in estimating the scattering introduced due to diffraction whether it occurs due to the limited size of surfaces or as edge diffraction When the method is activated the user specified scattering coefficients assigned to the surfaces should only include scattering which occur due to surface roughness diffraction phenomenon s are handled by ODEON The Reflection based scattering method combines scattering caused by diffraction due to typical surface dimensions angle of incidence 8 Snells law is the law of Billiard saying that the reflected angle equals the angle of incidence 6 75 incident path length and edge diffraction with surface scattering Each of the two scattering effects is modeled as frequency dependent functions The benefits are two fold e Separating the user specified surface scattering coefficient from the room geometry makes it easier for the user to make good estimates of the coefficients that will be in better agreement with the ones that can be measured In many cases a scattering coefficient of say 5 for all smooth surfaces may be sufficient e Scattering due to diffraction is
116. f all surfaces which has been assigned that material the material will not change in the material library in the right side of the Materials List Scattering coefficient or diffusion coefficient A scattering coefficient is assigned to each surface This scattering coefficient accounts for the roughness of the material at the mid frequencies around 700 Hz and it is expanded during calculations in order to take into account the frequency dependent behaviour of scattering using typically frequency functions for scattering coefficients This coefficient is taken into account during the ray tracing if Room setup Calculation parameters Scattering method is set to Lambert The scattering coefficient can be assigned values between O and 1 Material Scattering coefficient at mid frequency Audience area 0 6 0 7 Rough building structures 0 3 0 5 m deep 0 4 0 5 Bookshelf with some books 0 3 Brickwork with open joints 0 1 0 2 Brickwork filled joints but not plastered 0 05 0 1 Smooth surfaces general 0 02 0 05 Smooth painted concrete 0 005 0 02 With the scattering coefficients above it is assumed that Diffraction surfaces and Oblique Lambert has been enabled in the Room Setup If this is not the case then a minimum scattering coefficient of 0 1 is suggested 0 3 may be more appropriate for disproportionate rooms such as class rooms If some details are not modeled in a room then the scattering coefficient may a
117. fine Grid page which is used for the grid response calculations as it is likely that you will want to speed up grid calculation 8 89 9 Achieving good results The following section discusses how to obtain good results and indeed what is a good result It is not a straight answer as to how the best result is obtained merely a discussion that may provide some ideas as to what can be done in order to obtain reliable results in a program such as ODEON The desirable precision subjective limen Before discussing how to achieve good results it is a good idea to outline just what a good result is The subjective limen or just noticeable difference jnd on room acoustical parameters should give a good suggestion as to the desirable precision If the error between the real measured with some precision and the simulated room acoustical parameter is less the one subjective limen then there is no perceivable difference and the result is really as good as it can be so it would be senseless to look for more precise results In many cases it will be difficult or even impossible to obtain results at this precision and a poorer one will probably also be satisfactory for most purposes Parameter Definition Subj limen FDIS 3382 1 6 and CEI IEC 60286 16 7 for STI T30 s Reverberation time derived from 5 to 35 dB of the 5 decay curve EDT s Early decay time derived from O to 10 dB of the
118. floor surfaces on a layer named Stage floor the sidewalls on a layer named Sidewalls etc If you are modeling subdivided surfaces such as Upper wall and Lower wall because you wish to be able to assign different materials to these parts of a surface it is advisable to model these parts on different layers in order to avoid that ODEON glues these surfaces together described below If a 3 54 drawing is subdivided into layers this also makes it easier to assign materials to the surfaces in the Material List in ODEON because materials can be assigned to all surfaces on a layer in one operation Exporting a geometry from Odeon to IntelliCAD or AutoCAD When Odeon exports surfaces containing more than 4 points each these surfaces are exported using the 3DPOLY entity whereas all other entities are exported using the 3DFACE entity The 3DPOLY will appear as 3DPOLY lines in the CAD program and does not respond to the HIDE and RENDER commands like entities such as 3DFACE do However using the REGION command it is possible to convert 3DPOLY s into REGION s which do respond to the HIDE and RENDER commands Before exporting from the CAD program Remember that BLOCK s are not supported by ODEON BLOCK s containing relevant 3D info must be exploded using the EXPLODE command in the CAD program in AutoCAD this may also be done by exporting the file to the 3ds 3D Studio Max format and importing it again as described in the section on 3DSOLIDS 3
119. ft speaker and job 6 right speaker for calculation of the two binaural impulse responses Click the Run All Jobs to carry out the calculations Ra Two channel real time auralization Select job number 5 in the Job List and click the Streaming convolution button This will open the Streaming convolution dialog Select the your stereo input file in the Source signal field The convolver will begin to convolve an mono version of the input signal with the BRIR which was calculated for job number 5 To obtain stereo auralization select BRIR number 6 as the Secondary BRIR for 2 channel auralization ODEON will begin convolving the left channel of the input signal through BRIR number 5 and the right channel of the input signal through BRIR number 6 the result being a stereo playback in our simulated room The process involves four convolutions in parallel mixing binaural signals level adjustment and much more luckily this is all taken care of by ODEON To learn more about the Streaming convolution please press F1 from within that display Please notice that ODEON allow the combination of BRIR 5 and 6 because the same Single Point response receiver and Receiver pointing towards source are used in both simulations after all the same person receiver can not sit at more than one place and have more than one head orientation simultaneously Offline convolution The offline convolution more or less repeats what you have tried with the real time convolver
120. ftmost table Auralisation on loudspeakers It is possible to create auralization files for playback on a surround sound system The operation of surround sound auralization is more or less a repetition of the process just described however there are different hardware requirements and a loudspeaker rig must be defined before Odeon can calculate a surround file which is suited for the surround setup available Hardware requirements for loudspeaker auralization In order to play the surround sound files which can be generated by Odeon a suitable soundcard such as a 4 1 5 1 or 7 1 surround soundcard must be installed on the computer and connected to a matching loudspeaker system The soundcard must also be setup correctly in order to recognize which loudspeakers system it is currently connected to in the relevant software application which comes with the soundcard Defining the speaker rig In order to create surround sound output enter the Auralization setup and check the Create 2D surround sound impulse response Secondly click the Define speaker rig button in order to define the positions of your loudspeakers If you have a common surround soundcard then click the button for the speaker system which best resembles your system e g a 5 1 system It is possible to fine tune the positions of the loudspeakers in the Speaker list table Odeon will use this information in order to make corrections for signal delay due to difference in distances from in
121. g to correctly estimate SPL or STI However for auralization the directivity pattern should be equalised with the inverse spectrum of that of the front axis of the natural directivity pattern as this spectrum is already included in the source signal i e the wave file with human voice recorded with a microphone at front axis Odeon 8 5 and later can manage to do both at the same time if only the source directivity is marked as natural i e to create correct estimates of parameters from natural sources while creating correct auralization where the overall spectrum is only included once Odeon is installed with some directivity patterns which have the word NATURAL attached to their names e g BB93_Normal_Natural So8 When natural directivity patterns are selected from within Point source editor a green natural label is displayed next to the equalization entry fields If having existing directivity patterns of natural sources which are 5 64 not marked natural this can be done using the ToollDirectivity patterns Mark So8 file as natural directivity When creating new directivity patterns this information is part of the input data Head Related Transfer Functions and digital filtering To create binaural simulations a set of HRTF s see Appendix C Vocabulary is needed The HRTF s are different from subject to subject and in principle you may measure your own ones and import those into ODEON using the Tools Create filtered HRTF menu entry in the O
122. g of voice stored in a Windows Wave file residing in the directory set in the Options Program setup Auralization Wave signal file Directory To play the selected signal file make sure this cell is selected then press the Alt S shortcut or the Play wave button Adjust the Rcd Lev recording level to 30 dB Then arrow right to the Job no column and select Job no 1 from the dropdown list Exit the Job no cell but stay on the same row and the corresponding 3D Source Receiver view is updated to show active sources etc Click the Run All button to convolve the signal with the BRIR If other calculations e g point response calculations have to be carried out before the convolution is allowed ODEON will manage this automatically Play auralization file through headphones Once the calculations have been carried out click the Play wave result button and listen to the result through headphones If you have selected the Signal file column in the Convolve BRIR and Signal file table the anechoic input file is played If any other column in this table is selected the convolved result file is played Convolving BRIR s with signals and mixing signals In the following we will assume that you have a stereo recording called MyStereoRecording wav stored on your computers harddisk in a 16 bit resolution sampled at 44100 Hz Toggle to the Auralization display ALT T First step is to set up two mono playbacks one playing the left channel of
123. geometry on three different layers Selected surfaces can be selected for display in the 3DView 3DOpenGL and the Materials list BoxColumnRoom Par HHH const L 40 const W 30 const H 3 const NumColX 4 const NumColY 3 const ColumnW 0 3 3 35 MTranslate 1 2 0 0 Layer Walls 1 000 0 502 0 000 orange colour Box 11w h tb walls in the room MPop modeling the columns for ColYCnt 1 NumColY for ColXCnt 1 NumColX MReset MTranslate ColXCnt L Num ColX I1 w 2 ColY Cnt W NumColY I1 0 NumbOffSet Auto Layer Columns 0 502 0 502 0 000 Box 1 ColumnW ColumnW h n columns in the room olive colour NumbOffSet Auto MTranslate 0 0 1 2 Layer Table plates 0 000 0 502 1 000 bluish colour Box 1 3 3 0 1 tb tables end end HHH Symmetric modeling Symmetric rooms can be modeled taking advantage of the ODEON convention for symmetric models This allows generation of symmetric or semi symmetric rooms with symmetry around the XZ plane Y O symmetric modeling is always carried out in the main coordinate system it does not take into account manipulations carried out using UCS MTranslate etc Modeling a surface symmetric around the main axis e g a reflector above the stage can be done using symmetric points Modeling left and right walls at the same time can be done using a symmetric double surface Symmetric points Surfaces symmetric around the XZ plane Y O can be made using symmetric points If defining the point Pt 2 1 0 1
124. h measured results ODEON uses the modified definition shown above equivalent to cosine pressure sensitivity The LFso parameter has a high correlation with the apparent source width ASW as shown in 29 LG80 Early late averaging OFF 1 M000 Hz LG 10log gt JE cos B dB 4 Nisin t 80 LG80 Early late averaging ON 1 Noz eo o0 LG 10log Zi gt de cos 8 E cos 8 E conf dB Nizsm Lt 72 1 80 1 88 The value of LG8O becomes equal to the value of Late lateral G total late lateral level re to the level the source produces at 10 m in the free field when an OMNI directional source type and a power of 31 dB Octave band is selected from within the appropriate Point Source Editor This parameter is suggested in 29 and has a very high correlation with the subjective parameter Listener envelopment LEV Do note In version 9 0 the summed energy is multiplied with 0 25 to be in accordance with the revised 3382 standard therefore results of the LG parameter calculated in version 8 are 6 dB higher than the results from version 9 0 Stage Parameters Stage parameters are calculated as a part of the Single Point response Auditorium and Combined versions only if the job only contains one active source the active source is a point source and the distance between receiver and source is approximately 1 metre 0 9 to 1 1 metre The parameters are called Support for early late and total energy and are d
125. he HRTFs Convolving the left channel of the BRIR and the right channel of the BRIR with a mono signal a binaural signal is created which when presented to the listener over headphones gives the impression of the three dimensional acoustics at a 102 particular position in the room It is also possible to simulate the recording of the BRIR s which is what ODEON does 103 Appendix D Specify Transmission through walls A new feature in Odeon 9 is the ability to handle transmission through walls taking into account multiple transmission paths allowing walls to have a thickness and to have different materials on either side of the transmission wall 4 Assigning transmission data Once a Type of a wall has been set to Transmission in the MaterialList it becomes possible to specify transmission data using the Edit transmission data for surface option shortcut Alt Y This opens a dialog where Reduction indexes can be specified in one third octave bands from 50 Hz to 10 kHz The data can be entered directly or copied from a spreadsheet or from a text file using the common shortcuts Ctrl C and Ctrl V see description below EJ Microsoft Excel Lydisolation eks xls oj x File Edit view Insert Format Tools Data Window Help Type a question for help X v f Light double wall ey ee AAA A 1 Sound Transmission Loss 53 80 100 125 160 200 250 315 400 500 630 85 SN EE TE E ESEE e Sheet1 Sheet2 Sheet3 I4
126. hese examples show four ways to model a box shaped room using plain numbers using constants using constants plus symmetric modeling and using the Box statement along with the MTranslate statement In each example the dimensions of the room are W L H 4 6 2 7 Below the box shaped room is modeled using plain decimal numbers Parametric sample Box FromPureNumbers par HHH Pt 1 0 2 0 Pt 2 0 2 0 Pt 3 6 2 0 Pt 4 6 2 0 ceiling points Pt 11 0 2 2 7 Pt 12 0 2 2 7 Pt 13 6 2 2 7 Pt 14 6 2 2 7 Surf 1 floor 1 2 3 4 Surf 2 ceiling 11 12 13 14 Surf 3 end wall 1 2 12 Il Surf 4 end wall 1 2 12 11 Surf 5 side wall 1 4 14 Il Surf 6 side wall 2 3 13 12 HHH Below the box shaped room is modeled using constants for the definition of W L and H Some of the advantages of using parameters in modeling rooms are that it makes changes to a model much easier allowing reuse and often it will also improve the clarity of a model data Parametric sample BoxFromParameters par The box measures are Width 4 metres Length 6 metres Height 2 7 metres HHH const wW 4 const L 6 const H 2 7 3 43 Pt 1 0 W 2 0 Pt 2 0 W 2 0 Pt 3 L W 2 0 Pt 4 L W 2 0 Pt 11 0 W 2 H Pt 12 0 W 2 H Pt 13 L W 2 H Pt 14 L W 2 H Surf 1 floor 1 gt 4 Surf 2 ceiling 11 gt 14 Surf 3 end wall 1 2 12 11 Surf 4 end wall 1 2 12 11 Surf 5 side wall 1 4 14 Il Surf 6 side wall 2 3 13 12 HHH Below the box shaped room is modeled using
127. ical surfaces are modeled using the RevSurf statement Notice that the number of points created by the CountPt statement is one higher than the number of sections in the RevSurf statement The bottom and top of the room is modeled using the Surf statement notice that points used by these surfaces are referenced using the statement 100 gt 100 Sections 1 rather than writing each of the sequential points this is not only a faster way to write things it also allows a rapid change to the number of sections in the cylinder by simply changing the N constant Parametric sample a cylinder RevSurfCylinder Par HHH constN 16 const R 15 consttH 10 CountPt 100 N 1 R CosD PtCounter 360 N R SinD PtCounter 360 N 0 CountPt 200 N 1 R CosD PtCounter 360 N R SinD PtCounter 360 N H RevSurf 300 100 200 Sections cylinder walls Surf 100 Circular floor 100 gt 100 N 1 Surf 2 Circular ceiling 200 gt 200 N 1 Hit Modeling a box shaped room with columns in two dimensions using two level For End constructs When modeling geometries having more than one level of symmetry it is advantageous to use For End constructs This example shows how to model columns in two dimensions in a room using a two level For End construct Each column is created using 8 points and 4 surfaces thus the numbering used by points and surfaces is incremented by 8 each time a column is created This is done by incrementing the predefined variable NumbOffSet by eight for e
128. ilable from the Single Point response window please press F1 to consult the online help You may also select the page of interest and investigate the menu which in response appears at the top menu bar As a last option play the Binaural Room Impulse Response through headphones using the Ctrl l keystroke If the Multi option had been checked you would also be able to view the Multi point response results and if the Grid option had been checked and a receiver grid had been defined you would be able to view the Grid response results These topics will be covered below Do note that a result can not be viewed before it has been calculated one a result has been calculated the relevant cell in the Joblist will turn green in order to indicate that this result is available of Calculate Multi point Activate the Multi option from the Job list by checking the Multi option for job 4 then click the Run all or Run Selected Job button When the calculation has finished select job number 4 in the Job list and click the View Multi button to view the Multi point response results To learn more about the results and options available from this display press F1 You may also select the page of interest and investigate the dropdown menu which as a response appears in the top of the program window Note that point responses calculated using the Multi point response option are calculated much faster than Single point responses because no filters are created fo
129. ill now start calculating the Grid response for this job this may take a while When the calculations is finished select job number 1 in the Job list and click the View grid button to view the grid results To learn more about the results and options available from this display press F1 z zil Calc ulate Reflector Coverage Enter the Define reflector surfaces menu and select the podium ceiling surface surface 3001 Then click the Calculate reflector coverage button on the main toolbar to calculate the reflector coverage for the selected surface s Reflector coverage calculates the coverage provided by chosen reflecting surfaces at the first order reflections or up to fifth order if so desired using the dropdown menu or shortcut keys 1 through 5 This is an efficient tool for investigating whether the receiver area is covered by the reflectors or not and if the reflectors are positioned correctly The 3DBilliard display may also be useful for this purpose 3D Investigate Rays The 3D Investigate Rays display visualises the ray tracing as it is carried out during any point response calculation By default its calculation parameters are also set up as the parameters used for the point response calculations Single Point Multi and Grid This display is a very valuable tool for testing new room models e g to detect missing or misplaced surfaces It may also give an impression of what is happening in the calculations e g the effect of
130. ill usually have its max level at its polar axis 10 4 Creating a new directivity pattern using a text file as input Another way to create new patterns is to enter the data describing the directivity pattern into an text input file Depending on the data available and the complexity of the source one of three different text formats may be used Once the text input file has been created in one of the formats specified below e g in the Odeon editor OdwEdit it can be translated into an ODEON Directivity file which can be applied to any point source from within ODEON To translate the created text file into an ODEON directivity file Select Tools Create directivity So8 from ASCII file DAT Open the input file you have created Specify the name of the directivity file pattern you wish to create Select whether you wish a Calibrated source or not Apply calibration data as prompted for Applying Calibration Creating a new directivity file you will be prompted whether to create a calibrated source or not Calibrated source Sound Power Level 0 dB re 10E 12 Wat 1 kHz YES NO Calibrated Sources Press YES if an absolute level is not relevant to the directivity pattern an example on this could be the OMNI or SEMI directional directivity pattern When selecting a calibrated source no data apart from the ASCII input file are required The directivity represented by this file is preserved but the values are simply shifted by a con
131. ing a transparency coefficient greater than zero will cause the Image Source Method to be discarded for rays hitting such surfaces only relevant for point sources The Transparency value should not be used for modeling sound transmission through walls instead use the wall type for this purpose see below Type The wall Type can be set to Normal Exterior Fractional Transmission The type Normal Exterior and Fractional relates to the way Reflection Based Scattering is calculated for sound reflecting from the surfaces Transmission is for walls which transmit sound to another room e Normal is the default value which results in default handling of scattering and diffraction taking the Reflection Based Scattering method into account if it has been enabled in the Room setup e Exterior forces a surface to be handled as an exterior surface even if it was not detected as such by Odeon the result is that less diffraction is applied at the lowest frequencies where offset in the wall is not sufficient to result in low frequency diffraction e Fractional should be used for surfaces which are fractions of a bigger whole e g surfaces being part of a curved wall or a dome should not cause diffraction due to their individual area that is the individual surfaces do not provide any significant edge diffraction When setting the type to fractional the surface area used for calculating the Reflection Based Scattering Coefficient is determined from the box
132. ion which may be based on numbers or constants and variables that has already been defined Example 1 Const CeilingHeight 3 4 Example 2 Const FloorLevel 1 Const CeilingHeight FloorLevel 3 Example 3 Const FloorHeight 1 Const Length 6 Const CeilingHeight FloorLevel Length TanD 30 Defining and reassigning variables The definition of variables must follow the syntax Var lt Name gt lt OptionalValue gt Example 1 defining the variable FloorLevel Var FloorLevel Example 2 defining the variable FloorLevel and assigning the initial value 0 Var FloorLevel 0 Example 3 reassigning a variable adding 1 metre to the FloorLevel FloorLevel FloorLevel 1 Remark The predefined variable NumbOffSet may be used like any other variable but has a special meaning because is offsets point and surface numbering This variable is useful if copying a part of a geometry from another geometry file it is also useful in connection with the for end statements Auto can also be assigned to NumbOffSet in doing so Odeon will automatically increment the value of NumbOffSet to be greater than any point and surface number previously defined This has the advantage that repeated point and surface numbers can easily be avoided without having to keep track on the numbers used the drawback is that slight changes in the geometry file may change numbers on many subsequent surfaces ruining the relationship between surface numbers and the material assign
133. ironment e g using the ODEON par format Once a model has been successfully imported by ODEON it is important to perform a thorough check geometries which look fine in the drawing program may still contain serious errors such as repeated misplaced or missing surfaces 3 4 1 CAD entities supported by ODEON Irrelevant drawing entities which are not supported Many CAD drawings are in fact 2D paper drawings rather than 3D models Such drawings do not contain sufficient information to create a 3D surface model and are ignored in the import process Examples of drawing entities which are ignored are circles dimensioning lines texts etc 2D drawing data may coexist peacefully in a drawing containing useful 3D data the 2D data are as stated simply ignored It is possible to convert a few 2D entities into model data useful for Odeon provided that it is done from within the CAD program se the 22D entities paragraph BLOCK s are not supported ODEON can not import entities which were inserted into a drawing as BLOCK s Any BLOCK in a drawing which contains relevant 3D surface data must be exploded using the EXPLODE command before exported to the DXF file Odeon will notify the user if the DXF file imported did indeed contain BLOCK s 3D surface entities supported by ODEON e 3DFACE e Poly meshes MESH WEDGE PYRAMID BOX CONE CYLINDER SPHERE DISH DOME TORUS EDGESURF RULESURF and any other entities based on poly me
134. issing The unique So AR edge s option will show where the missing ji zro a a surface should have been 3 6 Combining geometries It is possible to combine geometries imported from an external CAD program with geometry modeled in the Extrusion modeler or modeled in the parametric modeling format of Odeon A geometry imported from a CAD program or generated in the Extrusion modeler is always in the par format and as such they may be combined in the Odeon Editor When combining different geometries from different sources some facilities in the parametric modeling format may be quite useful NumbOffset CoordSys Unit MTranslate MRoteteX MRoteteY MRoteteZ MScale MReset and MPop Below is an example outline which illustrates how number of geometries can be merged together in one parametric file HHH CoordSys X Y Z 1 model data aissa 1 model data NumbOffset 1000 avoid reusing point and surface numbers which has already been used CoordSys YX Z sswap coordinate axes if needed MTranslate 0 15 20 Translate move geometries as needed 2 Model data 2 Model data NumbOffSet 2000 MReset s restoring default origo CoordSys X Y Z restoring default coordinate system More model data HHH tl Using the 3DOpenGL display for model verification This display is very useful for detecting holes in the geometries Especially if stepping outside the model Arrow back shortcut and rotating the mo
135. iver dependent part of the process is simply repeated for each source When more than one source is involved the response at a given receiver is simply the sum of the responses from the individual sources each delayed appropriately if a delay is applied to the source ODEON automatically takes care of handling which of the calculation and result files are currently consistent with user entered data erasing those that are no longer valid Thus in some situations you may experience that Trace Rays calculation files have already been done are still valid in other cases they have to be recalculated The Early Reflection method Early reflections in ODEON are reflections generated by point s sources while the reflection order is less than or equal to the Transition order specified in the Room setup Every time a ray is reflected at a surface the position of an image source which may or may not give a contribution to the response at the receiver is found The position of this image is defined by the incident direction and the path length travelled from the source to the surface via other surfaces in the case of higher order reflections ODEON checks each s image source to determine Sees whether it is visible from the cs receiver Images may be hidden s Ne because walls in the room block the reflection path to the receiver or because the receiver falls outside the aperture formed between the image source and the Figure 1 Visi
136. iver list e Grid response offering a calculated map of room acoustical parameters if a grid has been specified from the Define grid menu Setup a single point response and run it e Select source number 1 as the Receiver towards source for each of the jobs 1 4 Notice how the blue cross changes into red in the Source Receiver view indicating that it has been selected for the selected job e Select receiver number 1 as the Single Point receiver for job 1 2 3 and 4 e Activate source 1 in job one source 2 in job two source 3 in job three and all three sources in job four Deactivate source number 1 in job 2 and 3 You can see which sources are active in a selected job by looking at the 3D Source Receiver View e Click the Run all button in the local toolbar at the right side to run the jobs and the four Single Point response responses will be calculated g View Single point response Select job number 1 in the Job List and click the View Single Point response button when the calculations have ended to see the results You will find seven tab sheets available in the Single Point Response window displaying room acoustical parameters energy curves Reflection density reflectograms 3D reflection paths and Binaural Room Impulse Response filters BRIR You can view results for each of the four jobs by first selecting the job in the Job List then clicking the View Single Point response button To learn more about the results and options ava
137. izontal and vertical polar plots are known POLAR The first non comment line of the file should start with the word POLAR In the polar case there are four lines of data for each frequency band The first four lines are for 63 Hz the next four for 125 Hz and so on For a given frequency the first and last values must agree on all four lines since all the polar plots meet at the polar axe The first line of a group of four is the upward vertical polar plot as seen from in front of the source 12 o clock plot Then come the left horizontal plot 9 o clock plot downward vertical plot 6 o clock plot and finally the right horizontal plot 3 o clock plot As a minimum there must be 1 4 8 lines in a polar input file Elliptical interpolation When the DirectivityFileUtility translates the polar input file it has to interpolate values between the four polar planes given in the input data This is done using elliptical interpolation independently for each frequency band creating the 8 x 4 plots missing between the four input plots An example Polar_Omni dat on the polar input format can be found in the DirFiles directory created at the installation of ODEON When the complete directivity characteristics are known FULL The first non comment line of the file should start with the word FULL In the full case there are 36 lines of data for each frequency The first 36 lines are for 63 Hz the next 36 lines for 125 Hz and so on As a
138. l case of the Box statement is when one of the dimensions Length Width or Height is zero in this case only one surface is created The syntax of the Box statement is Box lt Number gt lt Length gt lt Width gt lt Height gt lt T B N gt lt optional name gt lt Number gt A unique number from 1 to 2 147 483647 for identification of the first point and surface in the Box Using the same number but with negative sign defines the box and its mirrored counterpart in the XZ pane Y O A Box will take up several point and surface numbers which must all be unique lt Length gt Length is oriented in the X direction on the figure lt Width gt Width is oriented in the Y direction on the figure lt Height gt Height is oriented in the Z direction on the figure lt T B N gt The 7 B N parameter specifies whether the Box should have a top and or a bottom The options are 7 B TB and N for none Insertion point The insertion point of the Box is always the centre of the floor bottom surface Special cases If one of the dimensions Length Width or Height equals zero only one surface is created Connection points The four foot points in Box are stored in PlistA The four top points in Box are stored in PListB The Box example shown was generated with the following code 3 37 BoxStatement par HHH const L 6 const W4 const H 2 7 Box LWH TB Walls floor and ceiling HE The Cylinder statement The Cylin
139. lassic stereo setup with a receiver position and the two loudspeaker positions To run this example you need to have a stereo recording stored on your harddisk as a Windows wave file in 16 bit resolution and at a sampling rate of 44100 Hz or to be able to use the soundcard as the input This file which does not need to be an anechoic recording for this demonstration should be residing in the directory set in the Options Program setup Auralization Wave signal file Directory z E Enter the Source receiver list Make a copy of the point source source 1 To do this select source 1 in the Source list then press the C shortcut to copy this will open the Point Source Editor with the new source change the Y coordinate to 4 and type Left source in the Description field Following the scheme above create a copy of source 4 change the Y coordinate to 4 metres and type right source in the Description field E Enter the Job list to carry out calculations First activate source number 4 in job 5 and source number 5 in job 6 then select the receiver and point towards which the receiver is oriented For both jobs you will be sitting in receiver position 1 looking towards source 1 therefore select source 1 as the Receiver towards source point and receiver 1 as the Single point receiver for both jobs source number 1 is not activated in Job 5 or nor 6 we are only using this dummy source as a an aiming point for the receiver You have now set up job 5 le
140. late 10 5 10 5 2 5 945 9 2 24 24 2 At the end of the file just before the sign type MReset in order to make the coordinate system neutral this is desirable when adding new surfaces to the geometry Click the Odeon icon inside the editor in order to save the modified geometry and reload it into Odeon Other coordinate manipulations to the geometry may desirable in particular the CoordSys statement described in section 3 2 1 may be useful Trouble shooting Problem with zoom or translation in the 3DView Model appears in a strange position on the screen and zoom translation does not work as expected This problem is probably caused by some small invisible and irrelevant surface s located at odd position s in the imported model Solution 1 Try importing the geometry once again with some of the entities unchecked turned off it may be that some of the entities such as 3DPOLY or the like were not intended to be surfaces Solution 2 Removing the unwanted surface e n the 3DView turn on the Modeling options M shortcut look out for odd positioned points e Move the mouse cursor to the position of the odd point read one of these point numbers e Click the OdwEditor icon to open the par file remove the point and try to reload the room by clicking the Odeon icon in the Editor Now Odeon will hopefully report an error stating a surface is referencing the point which no longer exists e Remove that surface along with ALL
141. le this is possible by editing the file using the OdwEdit editor which is also available from within the Materials list and following the ODEON material format Special Materials There are three special materials in the library e Material O transparent e Material 1 totally absorbent e Material 2 totally reflective Although the material library Material lig may be edited materials O 1 and 2 must remain as originally defined Data format for materials in Material Lis The data format for a material in Material Lig is very simple each material is described by to lines ID_Number Descriptive text up to rest of line a63 al25 a250 a500 alk a2k a4k aK 4 62 ID_Number must be a unique number between O and 2 147 483 647 Absorption coefficients on second line must be floating point within the range O 1 the line containing 8 floating point values 4 63 5 Auralization Combined and Auditorium editions only Although much effort has been made to make it as easy as possible to use the auralization capabilities available in ODEON its felt that a separate chapter is needed as this is where all the threads from room acoustics modeling signal processing wave signal files transducers psycho acoustics recording techniques etc meets In the description of auralization techniques special words are frequently used please refer to appendix C Vocabulary for a short description In this chapter it is assumed that you have tried the sh
142. like the one in the FeaT PiN left figure is to simply SPIOENE p n enter the same data as oe ee ETE displayed in the 2 i omi iee screenshot of the DEEA Extrusion Modeler in the a aes ae right figure however a _ S a ae ee few tricks may be found in a ESECG DEA xX the description below If sl pim modeling a room in the XY la Al Modeling plane then a chair may in effect be considered A Err i an extrusion which excludes the top and three of its Er sides In this example we will create a chair with the seat ps p p p gp it dimensions 0 4 x 0 4 and a back rest with the height of 0 4 Legs and other small details should be omitted To make things easier do the modeling around origo then move the chair to its final location when finished When modeling around the origo it becomes easier to read the dimensions of the seat of the chair and to use grid and snaps without the need to calculate dimensions of the seat e Set the snap size s to 0 4 metres Click the 4 points in the seat of the chair Insert or Esc toggles point input on off Change the Z coordinate in the chair to 0 4 metres in the Surface editor to define seat height Change dZ to 0 4 metres in the in the Surface editor in order to define the height of the back of the chair Uncheck Top in the surface editor Uncheck the 3 sides which are not the back of the chair in the Point editor Finish the surface by pressing the Insert or Esc key
143. lso need to be increased a coffered ceiling where the coffered cells have not been modeled may typically have a value of 0 3 to 0 4 for the mid frequencies around 700 Hz Transparency coefficient semi transparent surfaces A transparency coefficient is assigned to each surface this is a way to make the surface semi transparent This feature may be used for modeling many small surfaces in real rooms E g a reflector panel built from many small surfaces with space in between can be modeled as one large surface having a transparency coefficient of e g 0 5 The transparency coefficient can be assigned values between O and 1 e 0 0 is assigned to all solid walls This value should always be assigned to the boundary walls of the room otherwise rays will escape from the model e Very small transparency coefficients should be avoided unless the number of rays is increased substantially Instead consider modeling the surface as solid Using a transparency coefficient greater than zero will cause the Image source method to be discarded for rays hitting such surfaces only relevant for point sources Another problem is that only very few rays will be transmitted making the results on the other side of the surface statistically unreliable 4 61 e Very large transparency coefficients e g 0 95 should also be avoided Instead consider removing the surface from the model An easy way to do this is to assign Material 0 transparent to the surface Us
144. mber between 16 and 24 is suggested if it s a column only use six to eight surfaces lt Height gt Height is oriented in the Z direction in the figure below lt T B N gt The 7 B N parameter specifies whether the E evSurf2 should have a top and or a bottom The options are T B TB and N for none If Top or bottom may only be included if all of the points in the floor in the elevation surface are in the same plane Example on use of the MPt and E evSurf2 statements First the perimeter points point 1 to 23 at the floor level of an office environment is described using the MPt statement Then the elevation surface is created from these points creating the perimeter walls of the office with a constant height of 2 7 metres Perimeter points at the floor level Room created using the MPt and Elevsurf2 statements Demonstrates the use of MPt multi point and E evSurf2 Elevation surface statements 3 29 In this example the X coordinates are made in absolute values whereas the Y coordinates in most cases are in or de creased using the or options To create a closed FlevSurf2 that is the first wall joins the last wall first and last point in the series of points handled to the ElevSurf2 must be identical in this example point 1 and point 23 are identical If an elevation surface has 22 surfaces then 23 points must be made available to the E evSurf2 as in this example HE MPt I 23 000 7 48 10 76
145. mpty lines may be inserted anywhere in the file as long as they do not come between data items which should occur on one line Comment lines must begin with a colon a semicolon a slash or an asterisk The semicolon can also terminate a non comment line allowing a non comment line to be terminated with a comment A series of comment lines are started with a and ended with a both as the first sign on a line Reserved keywords predefined counters and constants The following keywords are reserved by ODEON and has a special meaning in the parametric modeling language Constant and variable statements Const Var Point statements Pt MPt CountPt Point lists statements Plist0 Plist9 ResetPList0 ResetPList9 PlistA PListB Surface statements Surf MSurf RevSurf CountSurf ElevSurf ElevSurf2 Hybrid statements Box Cylinder Cylinder2 Cone Dome Dome2 Loop statements For End Transformation statements Mreset MPop MScale MTranslate MRotateX MRotateY MRotateZ and for compatibility with earlier releases of ODEON Scale UCS Predefined constants PI 3 14159265358979312 Predefined variables NumbOffSet ONVert Predefined Counters PtCounter Coordinate system definition statements Unit CoordSys Debugging Facilities Debug sOn Debug 3 23 Defining constants Constants must follow the syntax Const lt Name gt lt Value gt where value is a mathematical express
146. mulate the binaural listening experience at a given position in the modeled space In the way auralization is used in ODEON one may think of auralization as the art of creating digital simulations of binaural recordings in rooms which may not be build yet The aim is to provide the same three dimensional listening experience to the listener as would be achieved in the real room at the given receiver position with the simulated source position s and signals HRTF s Head Related Transfer Functions In short terms the HRTF describes how an impulse arriving at a person dummy head is smeared out by diffraction phenomenon s from head and torso of the person While an incoming impulse is only 1 sample long this will result in an impulse response arriving at the right and an impulse response arriving at the left ear which may typically have a length of interest of some 2 3 milliseconds approximately 100 samples at a 44100 Hz sample rate or if you prefer a length of 1 metre or so this is what is described by the HRTF s A set of HRTF s used for auralization will typically contain a library for many different angles of incidence The HRTF s that comes with ODEON are those made available by Bill Gardner and Keith Martin at MIT Media Lab at http sound media mit edu KEMAR htm as well as those from the CIPIC Interface Laboratory at http interface cipic ucdavis edu index htm If you have the capability of measuring HRTF s it is possible to import
147. n Single Point Response Calculations 6 81 6 9 Calculation method for Reflector Coverage cecceceee eee e eset ee eee teeta eee teeta enaeneeneeaeeaes 6 81 7 Calculated Room Acoustical parameters cccecc cece eee ee ee ene EEE EE EEE nA SE En EE Ena EEE 7 83 8 Calculation Parameters Room Setup and Define Grid ccceeee eect ee eee eee e eee ee eee eeeeaeeaes 8 87 vii 9 Achieving good results cece eee eee een neta nents 9 90 921 SourceS IOP ONOl snes a etd Mee eed Mea ed hubs a E a a ee a ee 9 90 9 1 1 Approximations made by ODEON ccccecccecee eee e eee e eee eee eee eee e eee n nee nat tant naeenaeeaas 9 91 9 1 2 Optimum Calculation parameters cccccccece eee ee ee eee Ee eA eee Eee EGE ESE ESE Ena Eee 9 91 9 1 3 Materials ADSOrPtion datar esrden tedapan i EEE SESE EGE EEE EAE 9 92 9 1 4 Materials scattering coefficients cece cee e eee eee eee eee eee eee ena eet eee eee 9 92 9 1 5 MEGASUREMONES i528 4 caine se cestecls ots cca aces aoa oe sa a cuvee nea ou vanne E ogeancinonbacatacnmacneaes 9 92 9 1767 Receiver position s orci ss ncekeae volatiles ue edn heeds hain d ea cee 9 92 9 1 7 Source Receiver distance sssssssssssssssreessssssssssseereceeerereerersrssssssssrseseeeesesessees 9 92 9 1 8 Minimum distance from the receiver to the closest SUrfACE cccece eee ene teat eeeeeaeees 9 93 10 Directivity patterns for POINt SOUICES cece
148. n using directivity patterns that has been marked as NATURAL please see chapter 5 for further information 1 3 3 Upgrading from versions earlier than version 8 When upgrading from versions earlier than version 8 it is essential to learn about the new methods for handling of scattering Chapter 4 covers the material properties to assign to surfaces chapter 6 covers the calculation principles including handling of scattering and chapter 8 covers the choice of calculation parameters 1 3 4 Major upgrade If performing a major upgrade typically a full version number or more e g from version 8 to version 9 then Odeon will install to a new directory for that version without changing the existing installation If you have no wishes to use the old version of Odeon then it is suggested to uninstall the version s using the Windows Start Control panel Add remove programs feature If keeping an earlier version be careful not to mix the use of old and new versions although we do strive to maintain forward compatibility we can not guarantee that a room which has been loaded into a new version of Odeon will also load in an older version without problems 1 3 5 Upgrading from version 3 and earlier If you upgrade from a version earlier than 3 0 then we do recommend that you read carefully through the manual as if you were a newcomer to ODEON There are a huge difference between the early versions of Odeon and the Odeon software as it is tod
149. nd go to the paragraph Activate sources Otherwise if you are running the Combined edition continue below defining a line and a multi surface source E Define a line source Combined edition Click the New line source button to open the line source editor Enter the values x 4 metres y 2 metres z 2 metres Length 2 metres and Azimuth 135 Finally set the Overall Gain to 65 dB To save the new source just close the Line source Editor and confirm 1 Hint Use the Tab or ShifttTab keys to move between fields Depending on the language selected on your computer or is used as decimal point The decimal separator to use internally in ODEON may also be selected from the Options Program settings Other settings entry 2 5 95 Define a multi surface source Combined edition Click the New multi surface source button to open the Multi surface source editor Select surface 2001 End wall behind podium for this source and click the Invert normal button or shortcut Ctrl I to make the multi source radiate into the room a surface in a multi surface source can radiate energy form one of its two sides or from both its sides Finally set the Overall gain to 65 dB To save the new source just close the Multi surface source Editor and confirm Surface source Combined edition The facilities of the surface source are fully included in the multi surface source the Surface source is only available for backwards c
150. ndary surfaces this means that surfaces such as doors or windows which may be modeled as being slightly on the inside of the boundary walls will still be considered as boundary surfaces Interior surfaces are displayed in a green colour teal in the 3DView whereas boundary surfaces are black so a change to the Interior margin will be reflected in this display when the Room Setup dialog is closed The measure tells Odeon that effective scattering provided by boundary room surfaces should be restricted below a frequency derived from this measure see the manual for details To get an idea of our suggestions to this value please look into the geometries supplied with the installation of Odeon whether a value of 10 or 20 centimetres is chosen may not be critical but for rooms with a very jumpy boundary it should be considered to specify this parameter Key diffraction frequency Default is 707 Hz in order to obtain the best result in the mid frequency range for speech and music This is the frequency at which diffraction is calculated for the ray tracing part of calculations All other parts of point response calculations take into account frequency dependent scattering Only in special cases where the focus is on another frequency range should this frequency be changed 8 87 Scatter coefficients gt Siim to be handled uniformly From published material on measured scattering coefficients there seems to be a general tendency that modest scat
151. ne filters are installed with ODEON namely the HeadsAndPhones EE and HeadsAndPhones EC directories The first directory contains a set of HRTF s which was measured on a live subject with blocked ear canal by the CIPIC Interface Laboratory 41 along with our matching ee hph headphone filters The later contains the well known Kemar HRTF s which includes ear canals along with our matching ec hph filters One of the directories can be selected in the Options Program setup Auralisation setup dialog once this is done matching HRTF s and headphone filters can be selected in the same dialog as well as in the Auralisation setup specific to the individual room If installing new HRTF s or installing some of the additional CIPIC data from the installation disk contained in the Additional HRTF_data_for_Auditorium_and_Combined zip file Headphone filters are acceptable in the wav format in that case the filters should contain the impulse response s of the headphone as measured on a dummy head of the same type as the one selected in the HRTF drop down menu i e with or without ear canal or a corresponding ear coupler The filter may be one or two channels two channel is desirable if compensating a specific headphone A measuring program such as DIRAC 49 may be suitable for the measurement of the impulse response of a headphone The creation of the inverse filter to be used is taken care of by ODEON Adjusting levels Sound Pressure Level is
152. ng had been assigned to the surfaces in the room A classical example on this is the box shaped room where a flutter echo can be removed changing the angle of a surface by a degree or two 3 2 Modeling rooms by typing it into a text file 3 2 1 The ODEON Par modeling format language Geometry models can be made using the parametric modeling language which is built in to ODEON The model data are typed into a text file given the file extension Par using the modeling language described below You may use the supplied editor OdwEdit to create and edit your text files The ODEON modeling format is not case sensitive so upper and lower case letters can be used as desired 3 21 A simple modeling example At its simplest but not fastest a floor with the dimensions 4 x 4 metres can be defined as follows using the reserved keywords Pr and Surf in order to define points and surfaces FloorSurface Par HHH Pt Pt Pt Pt Surf 1 HH NN AWN wR SARS RASS esses A One may chose to model the room point by point and surface by surface as in the example above however for many geometries it will be an advantage to use parameters to describe basic dimensions in the rooms and to use high level statements to describe multiple points and surfaces in a fast and flexible way Before starting your first large modeling project it is a very good idea to read through chapter 3 or at least skim it it will pay off in the end Another way to learn a
153. ng using the Ctrl A shortcut then right click the mouse on the drawing and select the Convert to Polyfaces other options may also work It is recommended to perform this operation on a copy of the CAD file rather on your original In AutoCAD 2000 the conversion process involves exporting to a 3D Studio Max file and re importing the exported file e Export the geometry into a 3D Studio file using the 3DSOUT command this does not change your current CAD drawing e Import the 3DStudio file just created back into a new clean drawing in AutoCAD using the 3DSIN command In this new drawing the above entities has been converted to Polyface entities which are supported directly by ODEON At the same time all entities contained in BLOCK s have been exploded making them appear explicit thus directly compatible with Odeon If Odeon reports of any of the unsupported entities when the dxf file has been imported this is because some 3D data is available in the DXF file in a format which can not be converted by ODEON Consider following the steps above in order to create a dxf file which can be converted by ODEON Do note that ACIS solid modeling extensions may not be available in all editions of the various modeling programs Using LAYER s in the CAD drawing Surfaces will when imported to ODEON carry the name of the layer on which they were drawn Use the layer name to give the different parts of the geometry different names e g draw the stage
154. nse file option is turned on reflections are processed in order to create a binaural impulse response BRIR First of all it is determined whether a phase shift should be applied to the reflection based on surface size and absorption coefficients of the last reflecting surface 31 Then the reflection is filtered convolved through 9 octave band filters Kaiser Bessel filters the ninth being extrapolated and finally the reflection is filtered convolved through two corresponding directional filters one for each ear Head Related Transfer Functions creating a binaural impulse response for that reflection This process is carried out for each reflection received at the receiver point and superposing all the reflections a resulting Binaural Room Impulse Response BRIR for that particular receiver point is obtained The actual order in which the filtering is carried out in ODEON differs somewhat from the description above otherwise the calculation time would be astronomic but the resulting BRIR contains the full filtering with respect to octave band filtering in nine bands as well as directional filtering B format filters for external decoding and Surround filters for loudspeaker playback Calculation of these impulse responses are based on the Ambisonics technique which is covered in 43 46 Most of the Odeon specific steps involved in the generation of these filters are similar to those used for generation of BRIR s there are however two differ
155. nt as 6 77 0 for d x cos 0 C edge Eo f E d x cos 0x f c 0 50 for d Xcos 0 lt C edge As can be seen scattering caused by diffraction is a function of a number of parameters of which some of them are not known before the actual calculation takes place An example is that oblique angles of incidence leads to increased scattering whereas parallel walls leads to low scattering and sometimes flutter echoes Another example is indicated by the characteristic distance a if source or receiver is close to a surface this surface may provide a specular reflection even if its small on the other hand if far from away it will only provide scattered sound sa 7 Log frequency Figur 5 Energy reflected from a free suspended surface given the dimensions w At high frequencies the surface reflects energy specularily red at low frequencies energy is assumed to be scattered blue f is the upper specular cut off frequency defined by the shortest dimension of the surface f is the lower cutoff frequency which is defined by the length of the surface Boundary walls and interior margin As long as surfaces are truly freely suspended surfaces they will act as effective diffusers down to infinitely low frequencies For surfaces which are elements in the boundary of the room such as windows doors paintings blackboards etc one should however not expect these elements to provide effective scattering down to infinitely lo
156. nt is one then the orientation is that of the traditional Lambert source and finally for all cases in between the orientation is determined by the vector found using the Vector Based Scattering method 6 79 Shadow zone Oblique angle 4 Figur 7 Traditional Lambert directivity at the top and Oblique Lambert at the bottom Oblique Lambert produces a shadow zone where no sound is reflected The shadow zone is small if scattering is high or if the incident direction is perpendicular to the wall On the other hand if scattering is low and the incident direction is oblique then the shadow zone becomes large If Oblique Lambert was implemented as described without any further steps this would lead to an energy loss because part of the Lambert balloon is radiating energy out of the room In order to compensate for this the directivity pattern has to be scaled with a factor which accounts for the lost energy If the angle is zero the factor is one and if the angle is 90 the factor becomes its maximum of two because half of the balloon is outside the room Factors for angles between O and 90 have been found using numerical integration Oblique Lambert attenuation factors Correction coefficient Oblique angle Figure 8 Correction factor for Oblique Lambert When the oblique angle is zero Oblique Lambert corresponds to traditional Lambert and the correction coefficient is one When the oblique angle is 90
157. nt source at a certain receiver is illustrated taking into account only two neighbouring rays up to the sixth reflection order Because we are dealing with a point source this figure illustrates the hybrid calculation method The calculation is carried out using a Transition order of 2 and all surfaces are assigned Scattering coefficients of 1 Thus rays will detect image sources up to second order and above this order they will detect secondary sources Both rays detect the image sources which will both contribute a reflection to the receiver because the specular reflection path between the source and the receiver is free and reflection points falls within the boundaries of the surfaces Although more than one ray detected the image sources they only contribute the detected image sources once this is obtained by having ODEON build an Image tree keeping track on this Each Image source being unique is one of the major advantages of the Image source model Above order 2 each ray generates independent secondary sources situated on the surfaces of the room The time of arrival of the contribution from a given secondary source is proportional to the ray path length from S to the secondary source plus the distance from the secondary source to the receiver The intensity of a contribution from a secondary source is attenuated as listed above 6 74 One of the advantages of the ray tracing method used in ODEON compared to more traditional methods is th
158. nu item Deleting calculation files or result files available from the Files menu item Archiving project files in one single compressed zipped file for efficient and safe storage or for easy posting by e mail available from the Files menu item e Tools for detecting errors in a new model e g warped or overlapping surfaces available from the Toolbar dropdown menu e Setup for printouts available from the Options Program Setup menu item e Export of calculated data in ASCII text format for use in a spreadsheet or other post processing 2 2 Short guided tour Industrial edition B n the ODEON application You will find the ODEON program at the Windows Menu Start Program files Odeon Odw Execute the program and begin the tour Slopen a room model to work on Select the Open a room model button to select a room The room files containing the geometries for ODEON carry the extension Par or Sur for compatibility with previous versions of ODEON and is plain ASCII text files following the format outlined in chapter 3 For this guided tour select the room model named Example par BZkoview Have a look at the room Whenever ODEON loads a room it is displayed in a 3DView This allows you to investigate the geometry and check it for errors etc Several facilities are available in the 3DView e g rotation zooming highlighting of selected surfaces and corner numbers etc Press Fi to get overview of the facilities and their u
159. o achieve a high degree of compatibility between software soundcards and loudspeakers Windows as well as the native software associated with soundcards are capable of remapping loudspeaker signals that is if the signals are mapped in the first place As an example a 7 1 soundcard may have a program e g SoundBblaster has an application called Creative Speaker Settings which allow you to select the output format to be 5 1 or indeed stereo if that is the layout of your loudspeaker system In the other end of the signal chain the same thing is the case if a 5 1 system is asked to play a mapped 7 1 signal then Windows will remap the signal in order to match it with the hardware available or rather the hardware which the system is aware of In order to achieve optimum results it is highly recommended that speaker rig defined in Odeon matches that of the physical loudspeaker rig and that the setup of the soundcard is also also in agreement with that Calculating surround files If the speakers have been correctly defined you may enter the auralization setup and calculate the surround results e g click the Run All Jobs button Once calculations have finished an extra button will be available in the toolbar in the right side of the Joblist allowing you to toggle between the binaural and surround sound mode if both options were chosen in the Auralization setup Click the button until the titlebar in the Joblist display Surround Mode At this point it sho
160. o but below O dB as possible in the Convolve BRIR and Signal file table and in the Mix convolved wave results into one wave file table in 5 66 order to obtain the highest dynamic range If using the Streaming convolution option available from the main display in the Joblist Odeon will maximize the auralization output level if changing input signal or BRIR from within this display you may press the Maximize Gain button to maximize the gain for the new setup Relative play back levels In some cases you ll be interested in obtaining correct relative levels e g for comparisons between different seats in a concert hall In this case you should remember to use the same recording level convolver level and mixer level in the samples to be compared it is a good idea to use the same input Signal file to make sure that levels are the same at this point If you wish to compare across different rooms you should also be careful to remember that source gains in the rooms corresponds If using the Streaming convolution option available from the main display in the Joblist Odeon will maximize the auralization output level so if you wish to compare different setups you should make sure to set the Gain in the Streaming convolution display to the same value Absolute play back levels for headphone auralization Setting the level to an absolute level so the subject presented to the auralization sample experiences the same level as would have been the case in the
161. oMax MicroStation Rhino or AutoCAD which is capable of creating 3D surface models and exporting these as dxf files as described in section 3 4 Finally you may combine the different modeling methods import a CAD model from a CAD program and extend or correct it using tools which come with Odeon No matter which approach you choose for modeling always check the validity of the models The room model must form a almost closed enclosure It should also be almost free from warped twisted duplicate or overlapping surfaces ODEON has several tools for checking models for such problems The tools are presented in section 3 5 It is suggested that you always use these tools when working on models of some complexity 3 1 Guidelines on room modeling Whether you choose to model your rooms by typing your rooms directly into a text file or using a CAD program there are considerations that are common to either case Some guidelines of general nature are given below 3 1 1 Default coordinate system To make it as easy as possible to operate ODEON the following orientation of room geometries should be applied using a concert hall as the example e X axis pointing towards the audience e Y axis pointing to the right as seen from the audience e Z axis pointing upwards 3 1 2 Recommended size of a surface The most important theoretical consideration concerns the size of surfaces in a room model The classical laws of geometrical acoustic
162. og2 8 3 Square Sar X Saqr 2 4 Square root Saqrt X Sqrt 2 1 41421356237309515 Radius Radius A B Radius 3 4 5 Absolute value Abs X Abs 2342 2342 Sign Sign X Sign 2 1 Sign O O Sign 3 1 Minimum number of two members Min X Y Min 23 12 12 Maximum of two numbers Max X Y Max 23 22 23 98 Appendix B References 1 Ondet A M and Sueur J Development and validation of a criterion for assessing the acoustic performance of industrial rooms J Acoust Soc Am 97 3 March 1995 p 1727 1731 2 ISO 14257 Acoustics Measurement and modeling of spatial sound distribution curves in workrooms for evaluation of their acoustical performance 3 ISO 11690 1 Acoustics 1996 Recommended practice for design of low noise workplaces containing machinery Part 1 Noise control strategies 4 ISO 11690 2 1996 Acoustics Recommended practice for design of low noise workplaces containing machinery Part 2 Noise control measures 5 ISO TR 11690 3 1997 Acoustics Recommended practice for design of low noise workplaces containing machinery Part 3 Sound propagation and noise predictions in workrooms 6 ISO DIS 3382 1 Acoustics Measurement of the reverberation time Part 1 Performance rooms 7 CEI IEC publication 60268 16 first edition 1998 Sound system equipment part 16 Objective rating of speech intelligibility by speech transmission index 8 G M Naylor amp J H Rindel O
163. oint like in time but in reality they are smeared out both physically and by filtering during measurement e Inaccuracies in geometrical modeling lead to inevitable displacements of reflections backwards and forwards from their true positions Clarity Early late averaging OFF Eo 80 Cy 10log dB 80 Clarity Early late averaging ON Eon Eo s0 Eoss Eo T Ego T Egg Cys oto dB Deutlichkeit Early late averaging OFF D Eo s0 E 0 00 Deutlichkeit Early late averaging ON 1 Eoas Eoso Eoss 3 Ep D Centre time Q co Sound Pressure Level SPL 10log E dB The value of SPL becomes equal to the value of G the total level re to the level the source produces at 10 m in free field as defined in ISO 3382 6 when an OMNI directional source type and a power of 31 dB Octave band is selected from within the appropriate Point Source Editor Lateral Energy Fraction Early late averaging OFF 80 gt E cos B t 5 LF yy Eo 20 Lateral Energy Fraction Early late averaging ON 72 80 88 ME cos B E cos B E cos B t 5 5 t 5 LF i z Eun Eo s0 an Fogg It should be noted that the original definition of Lateral Energy Fraction 6 assumes an ideal microphone having cosine directivity for energy Real figure 8 microphones have cosine directivity for 7 84 pressure In order that ODEON s predicted LFso values can be compared wit
164. old W and H Winkler Bauphysikalische Entwurfslehre Band 4 Bauakustik VEB Verlag fiir Bauwesen Berlin 1976 20 Meyer E D Kunstmann and H Kuttruff Uber einige Messungen zur Schallabsorption von Publikum Acustica 14 119 124 1964 21 Beranek L L Music Acoustics and Architecture John Wiley 1962 99 22 Ingerslev F and J Petersen Lydabsorberende Materialer Arkitektens Ugehefteno 3 1953 23 D hrkop H et al M rtel muring pudsning Teknologisk handbog SBI anvisning 64 2 edition Statens Byggeforskningsinstitut Hrsholm 1981 24 Gade A C Rumakustisk m leteknik s rtryk 14 til kursus 5142 Department of Acoustic Technology Technical University of Denmark Lyngby 1990 25 Gade A C Practical Aspects of Room Acoustic Measurements on Orchestra Platforms ICA 14 Proceedings Vol 3 paper F3 5 Beijing 1992 26 Beranek Leo How they sound Concert and Opera Halls Acoust Soc of Am 1996 27 Barron Michael Auditorium Acoustics and Architectural Design E amp FN Spon and imprint of Chapman amp Hall 2 6 Boundary Row London SE18HN UK 1993 28 Gade A C The Influence of basic design variables on the acoustics of concert halls new results derived from analysing a large number of existing halls Proceedings IOA Vol 19 Part 3 1997 29 Bradley John S Gilbert A Soulodre Objective measures of listener envelopment J Acoust Soc Am 98 5 1995 p 2590 2
165. ome the problems Hard materials Hard materials such as concrete are often listed as being 1 or 2 absorbing It may sound like a difference of 0 5 or 1 is not a significant difference However if a room is dominated by this material or if one of the dimensions of the room is a change from 1 to 2 is a relative change of 100 9 1 4 Materials scattering coefficients The knowledge on scattering coefficients is currently rather limited Hopefully in the future the scattering coefficients will be available for some materials Meanwhile the best that can be done is to make some good guesses on the size of the scattering coefficients and to do some estimates on the effect of uncertainty 9 1 5 Measurements Eventually the reference data which you may compare with simulated room acoustical parameters are not perfect We must accept some tolerances on the precision of the measured parameters 9 1 6 Receiver position s Common errors are e to base the room acoustic design on simulations in one or only few receiver positions e to place the receiver close to a surface e to use too short source receiver distance 9 1 7 Source Receiver distance Point response calculations made in ODEON are to be compared with point response measurements and as such the ISO 3382 standard should be followed To obtain good estimates of reverberation time the minimum source receiver distance should be used in order to avoid strong influence from th
166. ompatibility B Define a receiver Click the New receiver button to open the Receiver editor Enter the values x 18 metres y 5 metres and z 3 metres To save the new source just close the Receiver Editor and confirm Define other receivers at x y z 12 3 2 2 x y z 8 7 1 5 x y Z 21 1 3 6 We will get back to the receivers and sources under the point Calculating Point Responses Assign material properties Open the Materials List and see how to operate it in the Materials menu Assign the following material data to the surfaces in the model Surface 1001 1002 2001 2002 2003 2004 3001 3002 number 2002 2003 Material 901 905 702 702 702 702 702 702 Scatter 0 7 0 7 0 05 0 05 0 05 0 7 0 05 0 05 Hit the F1 shortcut to learn more about scattering coefficients and other material specifications zl Quick Estimate fast estimation of Reverberation Time From within the Materials List run the Quick Estimate to get an idea of the order of the size of the reverberation time Note the longest reverberation time This calculation is very useful while assigning materials for the evaluation of different materials and their impact on the overall reverberation time Before leaving the Material list you may want to try this out by selecting different materials It is also possible to select among the defined sources However the source position will only have minimal
167. oms with strong decoupling or uneven distribution of absorption area you might wish to switch this setting off Decimate late rays is by default on Number of Rays Job calculations only The Number of rays to be used for the calculations is automatically set by ODEON the number is specific for the room loaded and will usually be sufficient for reliable results The number of rays specified is used for each source in a calculation To improve the reliability of the results increase this number and switch off the Decimate Late Rays option To decrease the calculation time used for job calculations decrease the number this may be OK for rough sketch calculations Max reflection order Job calculations only Max Reflection order is a stop criterion which determines how many times a ray can be reflected Under normal conditions it should be as big as possible then the Impulse response length will be the actual stop criterion and Max Reflection order is only taken into account when stopping rays that has been trapped between two very narrow surfaces If the Max reflection order is set to zero then only direct sound is calculated Impulse response length Job calculations and Global Estimate Determine how many milliseconds of the decay curve should be calculated This is an important parameter f it is shorter than approximately 2 3 of the reverberation time Tso cannot be calculated because the dynamic range of the decay curve is less
168. on 2 2 is intended for the Industrial edition Most of the description on how to operate the program is found here If you are new to ODEON this chapter is a must Chapter 3 covers the geometry modeling This chapter is always recommended reading new releases of Odeon often include new facilities which can speed up the modeling process as well as tools for verification of geometries Some of the facilities are a parametric modeling language with support for symmetric and semi symmetric rooms use of constants variables counters loops etc extensive support for import of CAD models in the dxf as well as the 3ds 3D Studio Max format and a stand alone drawing program for modeling of so called extrusion models Tools for verification of room models are also covered in this chapter Chapter 4 deals with the materials to assign to the surfaces of the rooms absorption scattering and transparency coefficients Special materials that may speed up the modeling process and how to extend the material library is also covered in this chapter Chapter 5 deals with the auralzation options in ODEON Auditorium and Combined the hardware requirements how to publish calculated sound examples on the Internet or on audio CD s etc Chapter 6 introduces the calculation principles used in the ODEON program It should not be thought of as a thorough description of all the calculation principles used merely a short introduction that may give an idea on the
169. on and a demo version of the program To install the program a Double click on the folder with the name of the edition you wish to install b Run the Setup exe program in the folder and follow the instructions during the installation process this will install the ODEON program onto your computer c To run the program the supplied hardware HASP key must be inserted into the USB port on the PC or parallel port if it s a parallel key If you start the program without the hardware HASP key it can only be used in viewer mode On the disk you will also find the directories DemoVersion and Install Noise Explorer used for upgrading ODEON licences see upgrading your software licenses below ODEON Demo Version Free demo version which allows you to carry out all the operations available in Odeon Combined The only limitation to that program is that you cannot make any calculations to new or modified rooms You will only be able carry out calculations on the supplied rooms and to view results which has been calculated in a registered version of Odeon Feel free to pass on a copy of the demo version or if the demo has been downloaded from the Internet to pass on the odeon zip file The most resent demo version of Odeon can be obtained at http Awww odeon dk Installing the Demo Version Run the Setup exe program from the DemoVersion directory and follow the instructions during the installation process this will install the Odeon Demo
170. on time lcatculating point responses At this point we are ready to calculate point responses Two different point response calculations are available in the Industrial edition e Multi Point offering room acoustical parameters for all the receivers defined in the Receiver List at the Source Receiver List e Grid offering a calculated map of room acoustical parameters if a grid has been specified from the Define grid menu Setup a Multi point response and run it e Activate source 1 in job one source 2 in job two source 3 in job three and all three sources in job four e Turn on the Multi option for the jobs 1 to 4 in order to calculate the point responses for the four receivers you have defined Notice how the active sources are displayed in the 3D Source receiver display as you scroll through the Job list EB iewing results When the calculation has finished select job number 4 in the Job list and click the View Multi button to view the Multi point response results To learn more about the results and options available in this window press F1 You may also select the page of interest and investigate the dropdown menu which then appears in the top of the program window You can view the Multi point response results for each of the four jobs by first selecting the job in the Job List then clicking the View Multi Point response button If the Grid option had been checked and a receiver grid had been defined you would be able
171. options switched on 3 59 4 Materials This chapter covers material properties and the facilities available from within the Materials List 4 1 Special Materials Material 0 transparent Assigning Material 0 to a surface corresponds to removing the effect of the surface completely from all calculations Hence surfaces with this material assigned e Offer no hindrance to rays either in energy or direction e Are excluded from the calculated active surface area of the room and therefore do not affect the estimate of the room s volume produced by Global Estimate or Quick Estimate Reverberation This facility can be used to temporarily remove surfaces such as doors or reflectors from the room or to define a phantom surface over which an energy map a grid is to be plotted Material 1 totally absorbent The totally absorbent material Material 1 may be used for modeling outdoor situations e g an open roof This is the only material which will stop the rays during ray tracing and no reflections are generated from surfaces assigned this material The material list consists of a window containing two lists the surface list and the material library When selecting a surface in the surface list the surface is automatically highlighted in the corresponding 3D Materials window The Material list window consists of two parts e Surface List left part of the window e Material List right part of the window Some of the functions av
172. ort guided tour in chapter 2 1 The basis for auralization in ODEON is either Binaural Room Impulse Responses BRIR s or surround sound impulse responses BFormat is also available for the advanced user which can be calculated as part of the Single Point Response in the Job List if the Auralization Setup Create binaural filters or Auralization Setup Create 2D Surround Impulse Response option is turned on In this section only the binaural simulation is covered but most of the points also go for surround Auralization In short terms the BRIR is a two channel filter through which a mono signal passes from the sound source s to the left and the right ear entrance of the listener receiver Using convolution techniques to convolve a mono signal with the BRIR a binaural signal is obtained which when played back over headphones should give the same listening experience as would be obtained in the real room Mixing such binaural signals created with different source positions and signals but with the same receiver position and orientation multi channel simulations is possible e g simulating a stereo setup background noise versus loudspeaker announcements or singer versus orchestra itl istening to Binaural Room Impulse Responses As mentioned above the basis of binaural auralization in ODEON is the BRIR s which are calculated as a part of the Single Point Response Once a Single point response is calculated it is possible to play the BRIR
173. ot be clear which absorption coefficient should be applied at a reflection in case of overlapping surfaces Warps can lead to holes in rooms at edges of joining surfaces with erroneous results as a consequence and the surfaces will not be well defined Using the 3DGeometry debugger in ODEON ODEON will generate a list of warnings and a corresponding illustration in a 3D display whenever an overlap or a warp exceeds the value specified in the Room setup Model Air conditions dialog Overlapping surfaces is a tricky problem because it is usually invisible on 3D projections of the geometries however such errors in the model may lead to unpredictable results so always check models of some complexity for overlapping surfaces 3 6 2 Testing Water tightness using 3D Investigate Rays Testing a new model for water tightness i e whether it is completely closed may be done using a 3D Investigate Rays window The room model may not be watertight if Surfaces are missing from the model Surfaces are unacceptable warped Boundary surfaces have been assigned transparency coefficients greater than zero Boundary surfaces have been assigned Material O transparent Sources are located outside the room Before investigating ray tracing you will have to e Make the boundary surfaces of the room solid by assigning materials to them For the moment it does not matter what the materials are as long as they are not transparent Material
174. oubleshooting Odeon makes heavy use of facilities which are built in to the Windows operating systems If parts of the user interface in Odeon is malfunctioning or looking odd and your computer is running an installation Windows which has not been updated recently then it is not unlikely that an update to the operating system may help The Windows update is available at www microsoft com 1 3 Upgrading from previous versions If you are upgrading from previous versions of ODEON read on to learn about the changes in ODEON To learn about the revision history of Odeon please refer to the Help Contents Contents Whats new in Odeon 9 0 tab from within ODEON Below is a list of issues which you should be aware of when upgrading from previous versions 1 3 1 Upgrading to version 9 0 When upgrading to version 9 0 you should notice that the file formats used in version 9 0 is only forward compatible that is you may load the files from earlier versions of Odeon into ODEON 9 0 but loading a file set which has been loaded by ODEON 9 0 into an earlier edition of ODEON is likely to fail If for some reason you should wish to so anyway you should make use of the File Open and repair or in even earlier versions File Open in safe mode option instead of the normal File Open Room 1 3 2 Upgrading from versions earlier than version 8 5 Natural sources used for auralisation in the Auditorium and Combined editions are handled automatically in ODEON whe
175. ponding absorption coefficients to obtain the total absorption in the room ODEON also sends out particles from the source assuming diffuse conditions thus reflecting them in random directions keeping a count on how many times they hit each surface Surfaces that are hit very often then carry greater weight in the overall mean absorption coefficient of the room Surfaces which are not detected at all in the ray tracing process are left out of all calculations and surfaces which are hit on both sides are included twice in the calculation As a result the estimated reverberation time corresponds to the sub volume in which the selected source is located Note however that if a part of the area of a surface which is present in the sub volume is located outside that sub volume e g if two sub volumes share the same floor surface then area and surface estimates for the statistical calculations may not be entirely correct The classical mean absorption coefficient is given by Ysa s i where S and are respectively the area and absorption coefficient of the i room surface The modified mean absorption coefficient as experienced by the particles is _ LAG a i En where Hiis the number of hits on the i room surface In ODEON both of these mean absorption coefficients are inserted in the Sabine and Eyring formulae to calculate reverberation times the classical values are labelled Sabine and Eyring and the values using the modified
176. r for LFso LG80 and auralization The orientation of the receiver s in a particular job is set in the Job list by selecting a point source through which the receivers are looking This point source need not be active it may indeed be an inactive dummy source which is only used as an aiming point There are three kinds of point response calculations the Single Point Response the Multi Point Response and the Grid Response Ol ingie Point Response is calculated for a selected receiver position which must be defined in the Source Receiver list The Single Point Response is the most detailed calculation method allowing e Prediction of room acoustical parameters including stage parameters e Display of predicted Decay curves e Tracking of individual reflections in a reflectogram and display and tracing the reflection s in 3D displays of the room e g for tracking down echo problems e Auralization see chapter 5 of Multi point response calculates room acoustical parameters for all the discrete receiver positions defined in the Source receiver list lara Response calculates room acoustical parameters for a mapped receiver area The surfaces over which grids should be calculated are selected in the Define Grid display 2 13 The Auralization features are available from within the Job list Auralization is based impulse responses BRIR s and Surround Impulse responses which may be calculated as a part of the Single Point Response F
177. r 3 2 8 Root Root Y X Root 3 8 2 Round Round X Round 2 67676 3 Truncation Trunc X Trunc 1 7 1 or Int X Sine of an angle in radians Sin X Sin O O Cosinus of an angle in radians Cos radians Cos PI 4 0 707106781186547573 Tangens of an angle in radians Tan radians Tan PI 4 1 Cotangens of an angle in radians Cotan radians Cotan 180 O Hyperbolic Sine to angle in radians Sinh radians Sinh O O Hyperbolic Cosine to angle in radians Cosh radians Cosh O 1 Sine to angle in degrees SinD radians SinD 90 1 Cosine to angle in degrees CosD degrees CosD O 1 Tangens of an angle in degrees TanD degrees TanD 45 1 Cotangens of an angle in degrees CotanD degrees CotanD 90 O Inverse Sine in radians ArcSin Y ArcSin Sqrt 2 2 180 PI 45 Inverse Cosine in radians ArcCos X ArcCos Saqrt 2 2 180 Pl 45 Inverse Tangens in radians ArcTan Y ArcTan 1 180 PI 45 Inverse Tangens II in radians ArcTan2 X Y ArcTan2D 1 1 180 PI 45 Inverse Sine in degrees ArcSinD Y ArcSin Sqrt 2 2 180 PI 45 Inverse Cosine in degrees ArcCosD X ArcCos Sqrt 2 2 180 Pl 45 Inverse Tangens in degrees ArcTanD Y ArcTan 1 45 Inverse Tangens II in degrees ArcTan2D X Y ArcTan2D 1 1 45 Exponential Exp X Exp 1 2 71828182845904509 Natural Logarithm Ln X Ln 2 718281828459045091 1 Logarithm base 10 Log10 X Log10 100 2 Logarithm base 2 Log2 X L
178. r auralization use lal Define a receiver grid and calculate grid response Enter the Define Grid menu and select the two floor surfaces surface 1001 and surface 1002 Specify the Distance between receivers to 2 metres then click the Show grid button Close the Define Grid dialog to save the grid definition 3 Reflectograms are only used with point sources and will not contain any relevant information for line and surface sources If the Transition order is set to zero in the Room setup then the Reflectogram will at most contain one reflection the direct sound 2 7 Note If the Define Grid button is disabled this is because some process is open which requires data to be saved In this case it is probably the Estimate Reverberation display that needs to be closed To find this open window use the Windows menu item on the menu bar Other displays containing calculation processes may cause the same kind of disabling of miscellaneous options Hint The grid may also be used for easy positioning the point sources and discrete receivers which are usually defined in the Source receiver list To learn how to operate the 3DGrid display select the display and the 3DGrid tab in that window then select the 3DGrid Parameters dropdown menu Calculate grids Click the Job list button again Activate the Grid option from the Job list by checking the Grid option for job 1 then click the Run all or Run Selected Job button ODEON w
179. rdinary audio CD If a CD R drive is installed on your PC is quite easy to transfer the wave result files into an ordinary audio CD most CD R drives comes with the necessary software for this purpose Most people have 5 68 access to a CD audio player so publishing results on an audio CD makes is easy to send demonstrations to clients etc without worrying about whether they have a PC with a soundcard of a reasonable quality Again when publishing examples make sure that copyrights are not violated You are free to publish examples which are calculated using the anechoic examples supplied with ODEON you may also redistribute the same anechoic examples for comparison Remember to tell the end user to use headphones when listening to the samples 5 69 6 Calculation Principles 6 1 Global decay methods ODEON features two methods for calculating the Global decay of rooms e Quick Estimate which is available from the Materials List is the fastest method allowing quick evaluation of the effect of changes to materials This method should be considered only as a tool for preliminary results e Global Estimate is the most precise of the methods allowing high quality results 6 2 EJ Quick Estimate This method estimates a mean absorption coefficient which is inserted in the Sabine Eyring and Arau Puchades formulas to give an estimate of the reverberation time Instead of simply taking the areas of the surfaces and multiplying by the corres
180. real room is a bit tricky as it involves every part in the signal chain To obtain a reasonable correct level a first approach is to adjust the auralization output against levels of some kind of sound in the room in which you are e g if you are simulating voice try to compare the level of the playback with the level of somebody speaking in your room This method should make it possible to make a rough adjustment and it s certainly better than none A more precise method is to use the calculated SPLa as a reference if it is calculated at an absolute level e Present the auralization signal over a loudspeaker in the room in which you are sitting e Measure the sound pressure level in the room at the position where you will be sitting when listening to the auralization and adjust the output level of the loudspeaker amplifier until the measured Leqa corresponds to the calculated level At this point you have a physical reference level which can be used for calibration of you auralization playback level e Change between playing your auralization sample over headphones and over the loudspeaker while adjusting the level of the auralization playback until you are satisfied that the levels are the same This method is somewhat inspired by Bachausen and should at least in principle allow perfect calibration of the level the resulting level being within one subjective limen Headphones The binaural auralization results created in ODEON are bina
181. response from a source to a receiver This is the process used to in order to predict Single Point Multi Point and Grid Response results from within the Job list Source types calculation methods Responses from point sources are calculated using a hybrid calculation method where the early reflections are calculated using a mixture of the Image source model and ray tracing and the late reflections are calculated using a special ray tracing process generating secondary sources which radiates energy locally from the surfaces of the walls Responses from line and surface sources are carried out using the special ray tracing method Energy Reflection order The calculations carried out are divided into a two step process a receiver independent part and a receiver dependent part Trace rays the receiver independent part Trace rays is the receiver independent part of the Response calculations rays are being used to trace down possible reflection paths the result of this process can be reused for any receiver position in the room Whenever running a Single Point Multi Point and Grid Response calculation the necessary Trace rays calculation is automatically carried out if this has not been done already For point sources rays distributed equally in all directions on a sphere for line and surface sources the rays are sent out in 6 71 random directions following the Lambert distribution see section 6 7 Sending rays from a sourc
182. ror line and finally use the Mirror shortcut Ctrl M to create the full table The position of the mirror is easily changed if holding down the Shift key while pressing Right mouse and moving it if performing a very significant move in the horizontal or vertical direction this will toggle between a horizontal and a vertical mirror line Mirror manipulation Mouse operation Move mirror line toggle between vertical and horizontal mirror line Shift Right mouse button Rotating a surface To rotate a surface select the point in the surface around which the surface should be rotated then activate the Rotate dialog using the Ctrl R shortcut and enter the number of degrees to rotate the surface positive rotation angles are always counter clockwise CCW A surface can not be rotated around a point which is not included in the surface however this trick will do it insert the point of rotation into the surface e Select the surface e Bring it into editing state Esc or Insert shortcut e Add the rotation point it is not important where it is inserted in the sequence of points e Rotate the surface e Delete the rotation point from the surface Del shortcut looo hoo 12 00 13 2 tooo Moge W200 94 49 09 hoo I2 00 z r A A E T ete a S a anna caqacnnessns 2loo O ee p00 too A 0 00 j 00 42 00 E Lo R o yao S po 42 00 To rotate a surface around a point which is not included in the surface a Ins
183. s MTranslate MRotateX MRotateY MRotateZ MScale MPop and MReset included from version 4 21 allow far more flexibility For your own sanity it is not adviceable to mix the two methods The UCS command must follow the syntax UCS lt TranslateX gt lt TranslateY gt lt TranslateZ gt lt RotateZ gt The UCS command is used to create a User Coordinate System with its own X Y and Z translation It also allows a rotation around the Z axis specified in degrees All point definitions made after a UCS call will be created in the specified coordinate system The default coordinate system is defined as UCS 1 1 1 0 3 33 The UCS command corresponds to MReset MTranslate lt TranslateX gt lt Translate Y gt lt TranslateZ gt MrotateZ lt RotateZ gt If the UCS command doesn t fulfil your needs for coordinate manipulation you may use the matrix manipulation family MTranslate MRotateX MRotateY MRotateZ MScale MPop and MReset Scale The Scale command is mostly there for compatibility with previous versions of ODEON the coordinate manipulation functions MTranslate MRotateX MRotateY MRotateZ MScale MPop and MReset included from version 4 21 allow far more flexibility For your own sanity it is not adviceable to mix the two methods The Scale command must follow the syntaks Scale lt ScaleX gt lt ScaleY gt lt ScaleZ gt The scale command will multiply scale all the points generated after the scale call using the specifi
184. s active The 3D Edit Source Receiver menu will allow you to operate the 3D display e g use the SPACE key to switch between different predefined views Finally set the overall gain to 65 dB 65 is just an arbitrary value To save the new source just close the Point source Editor and confirm New sources are by default turned OFF therefore it will not be visible in the 3D Edit source display Press the SPACE key to activate the source for the current Job more on Jobs later on Hint Use the Tab or Shift Tab shortcuts to move between data fields Bahetine a line source Click the New line source button to open the Line source editor Enter the values x 2 metres y 2 metres z 2 metres Length 2 metres and Azimuth 135 Finally set the Overall gain to 65 dB To save the new source just close the Line source Editor and confirm 6 Hint Use the Tab or ShifttTab keys to move between fields 7 Depending on the language selected on your computer or is used as decimal point The decimal separator to use internally in ODEON may also be selected from the Options Program settings Other settings entry 2 15 4g Define a multi surface source Click the New multi surface source button to open the Multi surface source editor Select surface 2001 End wall behind podium for this source and click the Invert normal button to make the multi source radiate into the room a surface in a multi surface source can radiat
185. s are such that for the purposes of calculating how much energy is reflected all surfaces are considered to be infinitely large in comparison to the wavelength For practical room models surfaces are not infinitely large and ODEON is to some degree able to take into account the limited size of surfaces in calculations using the Reflection Based Scattering method Still ODEON is a high frequency model so surfaces should as far as possible be kept as large as possible don t use more surfaces than needed in order to mimic the geometry modeling a lot of small surfaces to achieve high geometrical fidelity is likely to produce worse rather than better results and its likely to increase calculation time It is difficult to put concrete limits on the size of surfaces which should be used there will always be a need for small surfaces to fill in awkward corners of the geometry but a rule of thumb may be to keep surface dimensions larger than one wavelength at the mid frequencies one wavelength at 1000 Hz is approximately 0 34 metres A typical model of a concert hall can typically be modeled with a surface count of say 100 to 1000 surfaces 3 1 3 Curved surfaces All surfaces in ODEON must be almost plane so curved surfaces have to be approximated by dividing them into plane sections The question of how finely to subdivide depends on the type of curved surface and how important the surface is 3 19 Convex curves naturally disperse sound
186. s created as results from the Mix convolved wave results into one wave file table will have the extension MixAuralnn Wav where nn refer to the row number in the table Mix No The output from surround auralization follows rules similar to those of the binaural ones the impulse responses are stored in wave files following the WaveFormatExtensible format where a signal is available for each loudspeaker channel in the specified surround setup The impulse response has the extension SurRoundnn Wav where nn refer to the relevant job number the convolved files have the extensions ConvSurRoundAuralnn Wav where nn refer to the row in the table Conv no and vice versa for the mixed files These files should be playable using the Windows Media Player Publishing audible results on the Internet To publish calculated demonstration examples on the Internet it may be useful to convert the result wave files into compressed mp3 files or wav Mpeg Layer3 files as download times for wave files can be lengthy One minute of compressed stereo signal will depending on the compression rate take up approximately 1 MB If publishing examples make sure that copyrights are not violated You are free to publish examples which are calculated using the anechoic examples supplied with ODEON you may also redistribute the same anechoic examples for comparison Remember to inform the end user to use headphones when listening to the samples Publishing results on an o
187. s issue is covered in Appendix D e Copying the project files generated by ODEON available from the Files menu item e Deleting calculation or result files available from the Files menu item e Archiving project files in one single compressed zipped file for efficient and safe storage or for easy posting by e mail available from the Files menu item e Tools for detecting errors in a new model e g warped or overlapping surfaces available from the Toolbar dropdown menu e Setup for print outs and graphics available from the Options Program Setup menu item 3 Modeling rooms Creating new room models is probably the most time consuming task in room acoustical modeling However good modeling practice will greatly reduce the time used for modeling and remodeling rooms In order to study a room in ODEON a file containing the description of the room s geometry will have to be created All subsequent derivative files and result files are created and managed by ODEON The file containing the room model must be written as an ASCII text file having the file extension Par the old ODEON Sur file format is also allowed though not described in this manual You can choose to create the geometry file either by typing the model data directly into a text file in the supplied text editor OdwEdit using the format described in section 3 2 using the Odeon Extrusion Modeler described in section 3 3 or a third party CAD program e g IntelliCAD 3DStudi
188. se Having assigned a room this is a good time to get familiar with the MDI concept Multiple Documents Interface At this point the title bar of the 3DView will be blue or some other colour indicating that this is the active window Being the active window the 3DView menu item is added to the menu bar next to the Toolbar dropdown menu You can operate the functions of the window using this menu or the shortcut keys displayed in the menu 7 petine sources and receivers Before any calculation can be carried out in ODEON one or more sources will have to be defined Of course a receiver will also have to be defined in order to calculate a point response In this guided tour we shall define a point a line and a surface source Finally we define a receiver Click the Source receiver list button at the toolbar to open the Source receiver list from which sources and discrete receivers are defined If the Source receiver list is already open but hidden behind other windows etc clicking this button will rearrange the windows as needed Dhetine a point source Click the New point source button in the local toolbar at the right side to open the Point source editor Enter the values x 3 metres y 2 metres and z 1 2 metres If you are not sure of the position of the source you can select the 3D Edit source display If you do so you should notice how the menu item 3D Edit Source appears on the dropdown menu when this window become
189. separate extrusion surfaces for the room the wall with windows holes the table and the windows Odeon 1985 2004 The Extrusion Modeler and file formats The output from the extrusion modeler comes in two formats the extrusion model can be saved in its own native format in an oes file This file can be edited and extended at a later point in the extrusion modeler e g if wishing to change width of the auditorium above to change some of the points in the drawing or to add other features The other format is the Odeon par format which is loaded into Odeon for calculations The parametric format can not be edited in the extrusion modeler on the other hand it may be edited to any degree of freedom if needed and it is possible to make use of the benefits of the parametric format described in section 3 2 e g when modeling geometric shapes such as cylinders and domes or when it is appropriate to describe parts of a geometry using parameters The par file can be edited in the Odeon text editor OdwEdit The 3DView available in Odeon is a useful tool when investigating or modifying an already existing file load the par file into Odeon study the room in the 3DView please see the help 3 48 text shortcut F1 available from within this display then make the changes in the editor which can be opened from within Odeon Using the Extrusion modeler inara narren rediri maa ee en ee ra E aaa G pe iii dim LEC Hemm laa i w
190. shes e Poly faces the PFACE entity and any entity based on poly faces 2 2D entities supported by ODEON LINE POLYLINE CIRCLE Odeon can import LINE POLYLINE ARC and CIRCLE entities so called 2 2D entities when the elevation height is set to a value different from zero using the ELEV command in the CAD program Using the ELEV command at least this is true in IntelliCAD and AutoCAD makes it possible to convert parts of a 3 53 flat line drawing into a 3D drawing typically a 2D floor plan can be converted into a set of vertical walls Use the CHANGE command in order to change elevation and height of these entities from within the CAD program 3DPOLY As an option it is possible to import 3DPOLY 3D polylines as if they were surfaces when these lines are closed polygons When Odeon exports surfaces containing more than 4 four points these surfaces are exported as 3DPOLY lines 3DPOLY lines will not respond to the HIDE or the RENDER commands when imported into e g AutoCAD however it is possible to convert POLYLINE s into REGION entities which are visualized correctly as surfaces in some CAD programs if the 3DPoly s are not plane this may not work In some cases it may be desirable to switch this import option off when importing to Odeon as the DXF file may contain such entities which the modeler did not intended to be included in the 3D surface model to be imported the entities may have been modeled for other reasons e g as as
191. sisting lines in the modeling phase POLYLINE when the POLYLINE is closed and the elevation height is set to zero This entity is not really a true surface however in some cases it may be use by some CAD programs including AutoCAD in order to bypass the limitation of maximum four points in a surface If a geometry which was exported from ODEON to the CAD program is to be imported into ODEON again this option should be on in order to import all 3D data In some cases it may be desirable to switch this option off as the DXF file may contain such entities which the modeler did not intended to be included in the 3D surface model to be imported the entities may have been modeled for other reasons e g as assisting lines in the modeling phase 3DSOLID REGION BODY recognized but not supported These entities are ACIS solid modeling entities which are not directly supported by Odeon However solid modeling is probably the most powerful way of creating 3D surface models allowing the use of commands such as UNION SUBTRACT INTERSECT SLICE INTERFERE etc and with a few steps it may be possible to convert these entities into something which is understood by Odeon In IntelliCAD Professional Pro 6 the 3DCONVERT command will convert above mentioned entities into entities recognized by ODEON Poly faces It is recommended to perform this operation on a copy of the CAD file rather on your original In 3DStudioMax select all the entities in the drawi
192. ssssssssrssssssrrersrrrrrrserrrrrrnrrrrreners 1 2 1 3 3 Upgrading from versions earlier than version 8 ssssssssssrrrsssrsrrrssrrrrrrsrrrrrrrnrrrrrrsere 1 2 1 3 4 Major upgrade cc cccacccescegccce micacsagcrcteses nn e a a a a 1 2 1 3 5 Upgrading from version 3 and earlier ccceee cece eee eee eee eee eee e teeta eee eee ed 1 2 1 3 6 Upgrading from version 3 1 and earlier ccceceee cece eect eee eee eee teeta ee anne ee tetas 1 3 2 Short guided OURS ccs secs eet cewecece ees eeee tet eegeeneeed ee siens ieee eee OH eed ee eee e meee 2 4 2 1 Short guided tour Combined and Auditorium editions ccccceee eee eens eee e eee ee eee eaeeas 2 5 2 1 1 Summary of the Calculation MethOdS cccceceeeee eee eee eee eee eee eee e ene ea tenet nee nae eas 2 13 2 2 Short guided tour Industrial edition 0 cceec cece eee eee eee eee eee eee eae neta ee enetaes 2 15 2 3 Pre calculated Rooms Round Robins c eceeee eee eee eee eee eee ee eee e nee e teeta neta 2 18 3 Modeling rooms ccctesstecedeeccededcandenedcckeoes a A aa O Ea OEA ERIE 3 19 3 1 Guidelines on room modeling sssssssssrsrssserrrssrrrrrrssrrrrnrserrrnnnurrnnurrerunnerrnnanuerennunuenen 3 19 3 1 1 Default coordinate SYSTEM 2 cece cc cee EEE REET DEEDES SEER EERE EEE Ed 3 19 3 1 2 Recommended size of a SUIfaCe 2 cece cece ener eee enna natant eens 3 19 31 3 CuURvedSuUitaCeS qcccuscisvecseceuectueataneducad
193. stant amount the same for all bands such that the sound power level of the source is O dB re 10 12 Watts at 1 kHz Please do note that the power in the other bands may differ from O dB You may still alter the overall power response of the source by applying an EQ however the power at 1 kHz will always end up as O dB the other bands shifted accordingly NON calibrated sources Electro acoustical sources machinery natural sources etc Press NO to preserve the sensitivity of an electro acoustical source or the absolute level of natural source e g a human voice When selecting the NON CALIBRATED source you are allowed to enter equalising electric losses zero for natural sources and a sensitivity at a selected frequency band zero for natural sources The addition of electrical sensitivity electrical input power and electrical loss values completes the data necessary to generate a source directivity file directly readable by ODEON 3 or later The DirectivityFilesUtillity program can perfectly well be used to generate a SO8 file for an electro acoustic source Various approaches may be used In the simplest case the ASCII input file should contain relative SPL values as for an electro acoustic source The sensitivity should be given as the true SPL obtained for the calibration band e g 1 kHz at a 1 metre distance transformed to that distance if necessary using the 6 dB per doubling of distance rule The EQ values should all be zero Such
194. statement and the curve must contain one more point than number of sections in the RevSurf lt CurveStart2 gt First point number in the second revolution curve The curve of points is typically created using the CountPt statement and the curve must contain one more point than the number of sections in the RevSurf The second curve must always contain the same number of points as the first curve lt SectionsInRevSurf gt The number of surfaces to be created by the RevSurf statement If creating a cylinder a number between 12 and 24 is suggested Although it is easy to create many surfaces in a revolution surface too many small surfaces should be avoided If the FirstSurfaceNumber is 100 and SectionsInRevSurf is 3 surface 100 101 and 102 will be created lt Optional name gt Optional user defined name for easy identification of the surface e g cylindric wall Example RevSurf 1000 100 200 6 Cylinder creates a revolution surface divided in 6 surfaces surface 1000 1005 This call requires two curves of each 6 1 points to be defined namely point 100 to 106 and point 200 to 206 If the two curves of points define corners in the lower and upper edge of a cylinder a cylinder of 6 sections is created see example room RevSurfCylinder Par Loops using the FOR END construct The For statement must follow the syntaks For lt CounterName gt lt CountFrom gt lt CountTo gt 3 31 lt CounterName gt Name of counter to be used b
195. stimates to the fraction of energy which is reflected specularily These factors takes into account the incident and reflected path lengths for ray tracing we have to assume that reflected equals incident path length angle of incidence and distance for reflection point to the closest edge on the surface all information which is not available before the calculation takes place 1 for f gt f 1 Jr f gt f K z K 5E tor pf 5E tor pf c a c a fx 2 w cos 6 i fi ee ae where a d m dg 2 d m 4 yoy If we assume energy conservation then we must also assume that the energy which is not reflected specularily has been diffracted scattered due to diffraction This leads to the following formulae for our scattering coefficient due to diffraction s 1 K K x d s In order to compensate for the extra diffraction which occurs when a reflection appears close to an edge of a free surface the specular component is reduced by a factor 1 se The edge scattering coefficient is defined to be 0 5 if the reflection occurs at the edge of a surface saying that half of the energy is scattered by the edge and the other half is reflected from the surface area If the reflection point is far from the edge the edge scattering becomes zero initial investigations suggests that edge scattering can be assumed to zero when the distance to the edge is greater than approximately one wave length therefore we define the edge scattering coefficie
196. stored Then if new materials are assigned to the surfaces the reverberation times can be recalculated instantaneously without repeating the particle tracing 6 2 1 Global Estimate This method estimates the global reverberation times T20 Tso using the method proposed by Schr der 48 the room volume and the mean free path and generates estimates of decay curves Particles are sent out in random directions from the source see section 6 7 and reflected using the Late ray reflection method see section 6 4 ODEON records the loss of energy in each particle as a function of time occurring because of absorption at room surfaces and in the air Summing over many particles a global energy decay function for the room is obtained The decay curve is backwards integrated and a correction for energy which is lost due to the truncation of the decay curve is applied This is analogous to an ordinary decay curve except there is no specific receiver The summation process may be carried on for as long as desired Evaluating results When the reverberation curve seems smooth derive the results If Tso values are shorter than T20 it is likely that the number of rays used were too small thus press the Recalculate button If the reverberation times are O the Impulse response length defined at the Room Setup page is probably too short 6 3 Calculation of Response from Sources to Receivers This section describes the methods used to predict the
197. surface s edge in either direction Below are two examples one with a donut shaped balcony floor and another with a cylindrical window opening in a ceiling In the donut example two rings of corners are created using the CountPt statement notice that the point 100 is equal to point 112 and point 200 is equal to point 212 The donut surface is created simply by connecting the inner and outer ring of points into one surface It doesn t matter whether one of the rings are created clock or counter clockwise The surface is created from the following list of points 100 101 102 110 111 112 200 201 202 5210 211 212 DonutSurface par HHH Const RI 10 Const R2 15 Const N 12 CountPt 100 N 1 R1I CosD 360 PtCounter N R1 SinD 360 PtCounter N 0 CountPt 200 N 1 R2 CosD 360 PtCounter N R2 SinD 360 PtCounter N 0 201 Surf 100 Donut surface 100 gt 100 N 200 gt 200 N HHH The window example shows how a cylindrical window opening is created in ceiling surface The interesting surface in this example is surface 1 the ceiling surface The surface is created from the following list of points 1 100 101 102 103 111 112 1 2 3 4 Ceiling WithWindowTube par HHH Const R1 0 75 Const R2 0 5 Const N 12 Pt1110 Pt21 10 Pt3 1 10 Pt 4 110 CountPt 100 N 1 R1 CosD 360 PtCounter N R1 SinD 360 PtCounter N 0 CountPt 200 N 1 R2 CosD 360 PtCounter N R2 SinD 360 PtCounter N 2 Surf 1 Ceiling 1 100 gt 100 N 1 gt 4 RevSurf 2 100 200
198. t ZMathExpression gt Use the CountPt statement to define a series of points using a counter This statement makes use of the predefined counter PtCounter which will run from 0 to MaxCount 1 producing the points with the numbers FirstPointNo to FirstPointNo MaxCount 1 Use the PtCounter in the expression of the x y and z coordinates to create the desired differences between the count points Example defining 7 points on a circle with a radius of 10 at Z 0 metres CountPt 100 6 1 10 CosD PtCounter 360 6 10 SinD PtCounter 360 6 0 Note First and last point in this series of count points are equal redundant This will typically be desirable when using the CountPt statement along with RevSurf statement Defining a single surface using the Surf statement A Surf surface is divided into two lines and must follow the syntax Surf lt SurfaceNumber gt lt Optional Description gt lt ListOfPointNumbers gt The Surf statement is used to define a single surface in some situations with symmetry two surfaces The Surf statement is constructed from two lines one identifying the surface by a number and an optional name and another with a list of corner numbers lt SurfaceNumber gt A unique number from 1 to 2 147 483647 for identification of the surface Using the same number but with negative sign defines the surface and its mirrored counter part in the XZ plane Y O The surface number may be defined using mathematical expr
199. t be considered freely suspended at the lowest frequencies 6 6 Oblique Lambert In the ray tracing process a number if secondary sources are generated at the collision points between walls and the rays traced It has not been covered yet which directivity to assign to these sources A straight away solution which is the one Odeon has been applying until now is to assign Lambert directivity patterns that is the cosine directivity which is a model for diffuse area radiation However the result would be that the last reflection from the secondary sources to the actual receiver point is handled with 100 scattering no matter actual scattering properties for the reflection This is not the optimum solution in fact when it comes to the last reflection path from wall to receiver we know not only the incident path length to the wall also the path length from the wall to the receiver is available allowing a better estimate of the characteristic distance a than was the case in the ray tracing process where dreti was assumed to be equal to dinc So which directivity to assign to the secondary sources We propose a directivity pattern which we will call Ob ique Lambert Reusing the concept of Vector based scattering an orientation of our Lambert sources can be obtained taking the Reflection Based Scattering coefficient into account If scattering is zero then the orientation of the Oblique Lambert source is found by Snell s Law if the scattering coefficie
200. t is possible to compensate for non linear frequency response of headphones When a headphone is selected Odeon will filter the output through a minimum phase filter with a frequency response inverse to that of the headphone A number of headphone filters are supplied with Odeon in Odeon s hph format Filters ending on ee hph are measured on a dummy head at the entrance of a blocked ear canal whereas filters ending on ec hph are measured at the end of the ear canal at the ear drum so to speak The selected headphone filter should match the HRTF used for example the Subject_021Res10deg hrtf doesn t have an ear canal therefore an ee filter should be used whereas the Kemar hrtf does have an ear canal so the ec filters should be used If the corresponding filter for the headphone used is not available then a generic filter matching the set of HRTF s may be used e g Subject_021Res10deg_diffuse hph If a diffuse field filter equalization selected the results are filtered in order to obtain an overall flat frequency response of the HRTF s that is the average frequency response of all the HRTF filters is calculated and the auralisation results are filtered with the inverse of that If using headphones which are diffuse field equalized most headphones attempt to be and a matching headphone filter is not available then the matching diffuse filter headphone filter can be used For your convenience two directories with matching HRTF s and headpho
201. t signals in fact are mono signals it will be a good idea to convert the resulting wave files into mono signals this will save space on the harddisk and avoid confusion whether a signal is stereo or in fact mono A standard wave file editing software which is usually included with the soundcard should be capable of doing the job If you have recordings which you have created yourself e g using a DAT recorder you should use a wave file recording software in connection with your soundcard in order to transform the recordings into wave files Most soundcards comes with a software program for recording and editing wave files which should be capable of this job Please note that the connection between the CD ROM drive and you soundcard is often an analogue one so if you record from this drive you ll not benefit from digital inputs on your soundcard resulting in a loss in quality Output signals The output signals from all binaural auralization are stored in two channel wave files and will have the same leading name as the room The result files being in the wave format makes it easy to edit and publish the results e g on the Internet or on audio CD s The binaural impulse responses files have the extension Jnn Wav where nn refer to the relevant job number The wave files created as results from the Convolve BRIR and Signal file table will have the extension ConvAuralnn Wav where nn refer to the row in the table Conv no The wave file
202. t surfaces to meet properly without either warping or using lots of small surfaces to fill the gaps allow the surfaces to cut through each other a little This will usually ensure a watertight result and has only minor drawbacks These are i the apparent surface area will be a little too big affecting reverberation times estimated using Quick Estimate Reverberation and the room volume estimated by Global Estimate ii crossing surfaces can look odd and hinder clarity in the 3D displays Do not try to include small geometrical details at the first attempt If there are some large surfaces which are basically plane but contain complex geometrical features e g a coffered ceiling model them at first as simple planes Then first when this room has been made watertight make the necessary alterations to the geometry file The simplified version can also be used in the prediction exercises to give some idea of the effect of the feature in question 3 2 3 Examples on parametric modeling This section will give some short examples on the modeling of rooms using the parametric modeling language of ODEON The options in this modeling format are many ranging from typing the model number by number to dedicated programming This section will try to give an idea on how to use the language and its keywords In the default room directory created at the installation of ODEON you may find several other examples on the Par format Four ways to model a box T
203. t the Windows Menu Start Programs Odeon Odw Execute the program and begin the tour el Open a room model to work on Click the Open a room model button to select a room Room files containing the geometries for ODEON carry the extension par or sur for compatibility with previous version of ODEON and are plain text files following the specifications outlined in chapter 3 For this guided tour select the room model named Example par E 3D View Have a look at the room Whenever ODEON loads a room it is displayed in a 3DView This allows you to investigate the geometry and check it for errors etc Several facilities are available in the 3DView e g rotation zooming highlighting selected surfaces and corner numbers etc Hit the F1 shortcut to get an overview of the facilities and their use Having assigned a room this is a good time to get familiar with the MDI concept Multiple Document Interface At this point the title bar of the 3DView will be bright blue or some other colour indicating this is the active window Being the active window the 3Dview menu item is added to the menu bar next to the toolbar dropdown menu You can operate the functions of the window using this menu or the shortcut keys displayed in the menu 2 e Define sources and receivers Before any calculation can be carried out by ODEON at least one source will have to be defined Also a receiver will have to be defined in order to calculate a point response
204. te ray density should be set to its maximum Number of rays ODEON by default specifies a suggested number of rays to be used in point response calculations This number is derived taking into account the aspect ration of the room as well as the number of surfaces in the geometry In short this means that Odeon will suggest more rays for very long room with many surfaces than for a basically cubic room with few surfaces This suggested number of rays will be sufficient for many rooms however in some cases more rays may be needed in order to obtain good results in particular in rooms with 1 Strong decoupling effects 2 Very uneven distribution of the absorption in the room Ad 1 If a dry room is coupled to a reverberant room then more rays may be needed in order to estimate the coupling effect well An example could be a foyer or a corridor coupled to a classroom If the room where the receiver is located is only coupled to the room where the source is located through a small opening then more rays are also needed Ad 2 In some rooms the reverberant field in the x y and z dimensions may be very different An example of this could be a room where all absorption is located on the ceiling while all other surfaces are hard Another example could be an open air theatre In particular if surfaces are all orthogonal while having different materials in the x y and z dimensions of the room and if low scattering properties on the surfaces are use
205. te to get an idea of the reverberation time Note the longest reverberation time This calculation is very useful while assigning materials for evaluating different materials and their impact on the reverberation time Before leaving the Quick Estimate you may want to try this out by choosing different materials It is possible to select among the defined sources However the source position will only have minimal effect on the global estimated reverberation time unless strong coupling effects are present in the room Al Room setup calculation parameters At this point you should have an idea of the order of size of the reverberation time To continue the series of calculations you should enter the Room setup and specify the Impulse response length The Impulse response length should cover at least 2 3 of the decay curve in this case 2000 ms should be sufficient To learn more about the other parameters available from this page use the F1 shortcut Global Estimate reliable method for estimation of reverberation time Run Global Estimate and let it run until you are satisfied that the decay curve has become stable then press the Derive results button Note the longest reverberation time The reverberation time differs from the values calculated by Quick Estimate because the room shape and the position of absorbing material are taken into account It is important that the Impulse response length in the Room Setup is at lease 2 3 of the reverberati
206. ter rays not visualised in the 3D Investigate Rays display is started taking care of the scattered sound which is reflected from this image source surface Example If all scattering coefficients in a room is 0 5 then the specular energy of a first order IMS is multiplied 1 0 5 and the specular energy of a second order IMS is multiplied by 1 0 5 1 0 5 The scattering rays handle the rest of the energy The early scatter rays are handled in a way which is indeed inspired by the way in which Odeon simulates surface sources actually each time an image source is detected Odeon will simulate a surface source which will emit Number of early scatter rays times the scattering coefficient of the image source surface The early scatter rays will be traced from the current reflection order and up to the transition order At each reflection point of the early scattering rays including the stating point a secondary scattering source is created The Late Reflection method All reflections that are not treated by the early reflection method are treated by the late reflection method Every time a late ray is reflected at a surface a small secondary source is generated This secondary source may have a Lambert Lambert Oblique or Uniform directivity depending on the properties of the reflection as well as the calculation settings ODEON checks each secondary source to determine whether it is visible from the receiver The late reflection process do
207. tering tends to be area based indeed the Lambert law is used for light whereas high scattering is better represented by uniform scatter In Odeon small scattering coefficients below Simt are handled either with the Lambert Oblique or Lambert algorithms whereas scattering coefficients above Simt are handled using uniform scattering Scattering coefficients in the context above are the Reflection Based Scattering coefficients if that option is activated a typical result of this algorithm is that reflections close to an edge will be handled with uniform scattering which is desirable Through empirical studies we have found that Siimit O0 5 yields best results If using a value of O then all reflections are handled uniformly and if using a value of 1 then all reflections are handled using Lambert or Lambert Oblique as was the case in Odeon 8 0 Decimate late rays Job calculations only For surface and line sources the number of rays is simply decimated for point sources the rays are decimated above the reflection order set by Transition order In short terms fewer rays than Number of rays are traced for the late reverberant tail but still a sufficient number to enable a good estimation of the reverberant behaviour The reasons for doing this are to enable faster calculations to be carried out without compromising the resolution of early reflections and to generate smaller ray history files If you are using ODEON in a research context or if you have ro
208. the borders between and inside the tables using the mouse Select the Mix No 1 in the Mix Convolved wave results into one wave file table The rightmost table displays the binaural results that are combined in this Mix Select row 1 in the table and select Conv No 2 the simulation of the playback of the left signal then select Conv No 3 in row 2 the simulation of the playback of the right signal Notice that you may also apply attenuation and a delay to each of the signals in the rightmost table of the mixer The attenuation corresponds to the attenuation knob on a mixer The delay is used for delaying the appropriate Convolved signal and should not be confused with a source delay An example where the delay feature could be useful is a simulation of an underground station where one signal is the train noise and another is the loudspeaker announcement the signals are not necessary of 4 In a stereo wave file the first channel is always the left channel and the second channel is always the right channel 2 10 the same length and you may want to delay one of the signals You may also use the delay if you wish to make noise sources which are playing the same noise signals less correlated e g if ten sources are playing the same cocktail party noise ten Single Point response Jobs and ten convolutions apply delays like O 2 3 5 7 11 13 17 19 seconds or another time unit You may mix up to 25 convolutions together Cal
209. the stereo signal another playing the right channel Left speaker playing left signal In Convolve BRIR and Signal file table setup Conv no 2 Row number 2 e Select a stereo signal file e g MyStereoSignal in the Signal file Column e Select channel 1 to select the left channel of the signal in the channel column e Select job number 5 in the Job no column to simulate the left channel being played through the left loudspeaker e Adjust the Rcd Lev Recording level to 40 dB or use the Overall recording level available in the Auralization setup Binaural settings this setting is effective on all convolutions Right speaker playing right signal In Convolve BRIR and Signal file table setup Conv no 3 Row number 3 e Select the same signal file as above e g MyStereoSignal in the Signal file Column e Select channel 2 to select the right channel of the signal in the channel column e Select job number 6 in the Job no column to simulate the right channel being played through the right loudspeaker e Adjust the Rcd Lev Recording level to 40 dB Mixing signals So far we have setup two mono simulations one playing the left channel and another one playing the right channel of a stereo signal To finish the stereo setup we need to mix the two binaural signals together The binaural mixer is in the right part of the auralization display If you are using a low resolution display not all of the display may be visible however you can drag
210. tion e g copy a room called MyRoom to MyRoomDL2Path and load the new copy when prompted for during the copy process e Delete receivers that are not wanted in the receiver path e Define the receivers needed e Finally make the Multi Point response calculation with the appropriate point source activated in the particular job 7 86 8 Calculation Parameters Room Setup and Define Grid Most calculation parameters are by default set by ODEON leaving you the choice of the essential parameters such as surface materials surface scattering coefficients source and receiver definitions The only parameter that should always be specified by the user is the Impulse response length If many surfaces are added to the room model in between calculations it is also recommended to re specify the Number of Rays For most of the parameters on the Room Setup page ODEON suggest values that can be considered safe if there are no special demands and the room model does not contain decoupled rooms or very uneven distribution of the absorption area When this is the case it may be desirable to increase the Number of Rays and uncheck Decimate late rays increase the Desired reflection density In some cases it may also be desirable to change certain parameters in order to conduct special investigations or to speed up the calculations in preliminary studies of a room In either case the parameters are described below Scattering method Job calculations Glob
211. uectacaianeudetaccdueatancegiadaeadueadwecdanatusnguemeaeedess 3 19 31 4 Whatto model esaerea aaa AE O E E a veto tenn acuneean E a ereeuntearaeues 3 20 3 2 Modeling rooms by typing it into a text file ssssssssssssnsnnrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrsnns 3 21 3 2 1 The ODEON Par modeling format language ssssessssssssssrrrssrrrrrrserrrrrrnrrrrrrnsrrrres 3 21 3 2 2 Creating a new Par file time saving hints sssssssssssssssrrrssrrrrrrserrrrrnnrrrrrrrnrrrrnns 3 42 3 2 3 Examples on parametric modeling ssssssssssssssrrrrssrrrrrrsrrrrnnnnrrrrnnnnrrnnnnnrrrnntnnrrrnnne 3 43 3 3 Odeon Extrusion Modeler 2 c0 2 c08 cessed vies ieee ieee eee dees ee eb ee eed eee ee dee bees 3 48 3 4 Importing DXF file Su sanna nE EAEE ENEN EA AA ie AAEE esse seen AEE EEES EESE E 3 53 3 4 1 CAD entities supported by ODEON cccceeceeee cette eee eee tees eee e eens eae eeat eee eaeeeanenaeeas 3 53 3 4 2 Performing the import in Odeon ccc cce eee ee eee eee e eens tenets 3 55 3 4 3 Editing the imported QeOMetry 2 ccecce cece eee ene nanan eerie 3 56 3 5 Model check im ODEON wscteisicistveccsistvastwascvacaeiotuentvaesaad a iudeved spuds exatuaddanasaeeeanbees 3 57 3 5 1 Bviewing the room Im a SDVICW sicir isinna nets eee ete eee ete ne ov en te ee eee eee 3 57 3 6 Combining geometries cece eee ee ee ee eee ena e neta eee nena 3 58 3 6 1 a 3DGeometry CEDUQQED 0 cece cece eee e eee eee ee ene
212. uld be possible to play impulse responses as well as convolved and mixed files from the auralization display using the surround sound hardware Trouble shouting surround playback There are a few reasons that we know of why the playback of surround files may fail the most obvious not mentioned here e Make sure that headphones are disconnected If the headphones have their own separate connection then the loudspeaker output may be disconnected when the headphone is connected e Playback of surround sound files in Odeon relies on the Windows Media Player which can play this type of multi channel files Make sure that the media player is up to date otherwise it may not support this type of files known as WaveFormatExtensible It should be possible to update the media player at http windowsupdate microsoft com e f Windows Media Player is not the default program for playback of wave files then the surround files may not play unless the software selected for default playback of wave files is also capable of playing this format The problem may be solved by telling ODEON where the Media Player resides this is done in the Options Program setup Auralization Surround Player field e g type C Program Files Windows Media Player wmplayer exe if this is where the media player resides If you are not aware of the location of the wmplayer exe file then you may locate it using the Search facility in Windows found in the Start menu Getting
213. ural signals which should be presented over headphones the objective being to reproduce the same sound pressure at the entrance of the ear canals and at the eardrums for that matter of the subject as would be obtained in the real room if it exists Soundcards A sound card is required in order to play back the auralization results and may also be useful if you wish to transfer anechoic signals to the harddisk As a minimum the sound card should be capable of handling signals in stereo in a 16 bit resolution at a sampling frequency of 44100 Hz To transfer signals without loss in quality to from a DAT recorder the soundcard should be equipped with digital input and output and the soundcard should be able to handle a sampling frequency of 48000 Hz It should also be considered whether the card is immune to electromagnetic noise which is always present in a PC and whether its analogue output for headphones is satisfactory For surround Auralization obviously a multi channel surround soundcards is needed along with the necessary loudspeakers and amplifiers Input signals for auralization anechoic recordings For auralization you will be using input signals to convolve with the calculated BRIR s Usually the signals will be anechoic signals although it may also be other types of signals e g if you are simulating an ordinary stereo setup in a room you will probably be using a commercial stereo recording The input signals to be used with ODEO
214. uralization supports binaural Auralization using headphones as well as Auralization using a loudspeaker setup surround sound El Real time streaming convolution binaural Auralization for headphone playback Select job number 1 in the Job List and click the Streaming convolution button This will open the Streaming convolution dialog Select the Voice Sabine Short file in the Source signal field this is an anechoic recording of voice stored in a Windows Wave file residing in the directory set in the Options Program setup Auralization Wave signal file Directory ODEON will start convolving the selected signal file with the selected Binaural Room Impulse Response BRIR in this case the BRIR for job 1 Listen to the output over headphones to benefit from the binaural quality of the auralization 2 8 The real time auralization facility allows auralization with two simultaneous channels e g simulating the left as well as the right part of an orchestra using a stereo recording as input signal also the input from the soundcard may be used directly for auralization that is on most computers this is possible if the windows play and record controls have been correctly setup Please press F1 from within the Streaming Convolution display to learn more about operating the options available Before leaving this example you may want to try the Listen to input signal option Listen to a stereo setup The next example will demonstrate how to set up a c
215. urfaces general 0 02 0 05 Smooth painted concrete 0 005 0 02 Table 1 Suggested scattering coefficients to use for various materials The given values are for the middle frequency at around 700 Hz to be assigned to surfaces in ODEON Suggestions may be subject to changes as more knowledge on the subject is obtained S Scattering due to diffraction In order to estimate scattering due to diffraction reflector theory is applied The main theory is presented in 5 6 the goal in these papers was to estimate the specular contribution of a reflector with a limited area given the basic dimensions of the surface angle of incidence incident and reflected path lengths Given the fraction of the energy which is reflected specularily we can however also describe the fraction sa which has been scattered due to diffraction A short summary of the method is as follows For a panel with the dimensions w above the upper limiting frequency fw defined by the short dimension of the panel the frequency response can be simplified to be flat i e that of an infinitely large panel below fw the response will fall off with by 3 dB per octave Below the second limiting frequency fi an additional 3 dB per octave is added resulting in a fall off by 6 dB per octave In the special case of a quadratic surface there will only be one limiting frequency below which the specular component will fall off by 6 dB per octave The attenuation factors Ki and Kw are e
216. ut Once in edit mode it is possible to change coordinates of the points insert or delete points and to move the surface using the mouse operations listed below It is also possible to enter the precise coordinates of points in the Point editor table which list the point in the selected surface so it is an option to draw a sketch using the mouse and then fine tune the coordinates afterwards in the Point editor table Operation on surface Mouse operation Create a new point in selected surface LeftClick mouse Select the point in selected surface which is closest to Mouse pointer Ctrl LeftClick mouse Move closest point in selected surface Ctrl Alt LeftClick mouse Move selected surface Shift LeftClick mouse Move selected surface when its not in edit mode LeftClick mouse 3 49 Manipulating the viewport The viewport can be manipulated using the shortcuts listed below It is possible to make changes to the view while drawing a surface View operation Mouse operation Scroll drawing area Right mouse button Zoom In Out Alt Left mouse button Snap to grid Snap to grid enables points new points or points being moved to be positioned exactly at the intersection of the grid lines In special cases the point can also be inserted at only one grid line when the other coordinate is that of an existing point see below Snap to existing points Snap to existing points enables points to be precisely locat
217. ven distribution of send directions Surface Sources and Line sources Combined and Auditorium versions only For these source types the send directions and send points are the same no matter the calculation type For each starting ray a random starting point is chosen at the line or surface source From this point a ray is send out in a direction following the laws of the Late ray method using a specular direction based on the Normal of the source and a scattered direction The method used here is similar to the Late ray reflection method of ODEON however the scattering coefficient used for weighting between the normal direction of the source and the scattered direction is one assign to the particular source from within the appropriate source editor Line Source Editor or Surface Source Editor With the present knowledge a scattering coefficient of 1 is suggested for these source types 6 8 Processing reflection data for auralization use in Single Point Response Calculations A typical point response calculation in ODEON includes some 100000 reflections per source receiver The reflections are calculated in terms of time of arrival strength in 8 octave bands and angle of incidence azimuth and elevation The information on size of the reflecting surfaces and absorption coefficients are also available as a part of the calculation Binaural filters for headphone playback When the Auralization setup Create binaural impulse respo
218. w frequencies From diffuser theory it is found that typical behaviour is that the effectiveness of a diffuser decreases rapidly below a cut off frequency which can roughly be defined from the depth of the diffuser wall construction being less than half a wave length Two octave bands below the cut off frequency the diffuser is no longer effective At the lowest frequencies however the dimensions of the room will provide some diffraction therefore the dimensions of the reflecting panel as used in the formulae for fi and fw is substituted with the approximate dimensions of the room at the lowest frequencies and a combination of surface and room dimensions are used for frequencies in between high and low frequencies It is worth noticing that it is not only the depth of the wall construction which enables the elements of the wall construction to provide diffraction also angling between the surfaces offsets e g the door being mounted in a door hole or the surfaces being made of different materials provides the phase shifts which results in diffraction Therefore it may be reasonable to assume that the boundary walls have a minimum depth of say 10 cm in order to account for such phase shifts The typical depth of a geometry s wall construction should be specified in the Interior margin in the room setup Odeon will use this number in order to distinguish between interior and boundary surfaces Once the margin has been entered and the room setup dialog h
219. w insul co nz 101 Appendix C Vocabulary The techniques of auralization make use of many of technologies and a lot of technical terms and abbreviates are commonly used in the literature Here is a short vocabulary to some of the most used expressions the vocabulary is not a complete description of the individual words the context under which the words are used are many and the subjects are rather complex Anechoic recording Anechoic recordings are recordings of sound sources made without any reflections from the surroundings contributing to the recordings A common problem with anechoic recordings are that they may often include to many high frequency components because they are usually near field recordings and because they are recorded on axis where these components usually dominate When using such recordings with auralization systems this may often result in unrealistic sharp s sounds especially in case of long reverberation times Anechoic recordings are usually recorded in an anechoic room but semi anechoic recordings may also be acceptable for use with auralization systems this could be out door recordings of machinery trains etc or studio recordings of music Auralization auralisation The term auralization was invented by Mendel Kleiner who gives the following definition Auralization is the process of rendering audible by physical or mathematical modeling the sound field of a source in a space in such a way as to si
220. y the For statement The counter is automatically defined by the For statement and becomes undefined when the loop finishes The counter can be referenced within the for end loop as an ordinary constant or variable if desired so lt CountFrom gt First value the counter takes The CountFrom value is considered an integer value If the number entered here is not an integer it will be rounded to the nearest integer value lt CountTo gt Last value the counter takes The CountTo value must be greater or equal to the CountFrom value The For statement will take CountTo CountFrom 1 loops The CountTo value is considered an integer value if the number entered here is not an integer it will be rounded to the nearest integer value The following example will produce the points 1 to 5 with the X coordinates 5 10 15 20 and 25 metres while the counter MyCounter loops through the values 1 to 5 For MyCounter 1 5 Pt MyCounter MyCounter 5 0 0 end When using For End constructs it should be remembered that point and surface number must be unique This is easily obtained by incrementing the special variable NumbOffSet appropriately in each loop An example on this kind of numbering can be found in the sample file ForColumnRoom Par where NumbOffSet is incremented by eight in each loop each time a new column which contains 4 surfaces and 8 points is created Sample room files ForRotunde Par BoxColumnRoom Par Unit The Unit statement is use

ODEON Room Acoustics Program

Contents

Download Pdf Manuals

Related Search

Related Contents