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User Guide Version 4 for Windows®

1. i 0 250 i Drag the cursor to the right or left until you reach the point where you want the displayed range to end a rubber band box will appear in the Waveform display to show your progress and release the mouse button After you release the mouse button the Range Locator Bars will snap to the bound aries of your selection and the main plot will change zoom in or out to display only the time range you selected Clicking in the area outside the plot in the Waveform Display with the left mouse button or pressing Shift Up Arrow on the keyboard will return the time range to the full extent of the wave file Page 100 SIA Smaart Acoustic Tools Version 4 User Guide Select Change First FFT Center to Peak Setting the center point for the first FFT in the transform series on the initial peak in the impulse response ensures that the peak data is altered as little as possible by the data window function in the first FFT frame All of the data windows provided in the Analysis module attenuate the samples closest to the beginning and end of each FFT frame to the largest extent leaving the samples closest to the center of the frame untouched for the most part To set or move the center point for the first FFT frame to any point on the Time Display plot hold down the Ctrl key while clicking on the plot with your mouse To reset the first FFT starting point to the beginning of the wave file hold down the Ctrl key while clickin
2. Page 88 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands Options Menu Commands All Most of the Analysis module s user configurable options and properties are set in the Options dialog box The Options dialog box is organized into 12 separate pages for different types of settings We also refer to these pages as tabs because each has an index tab at the top that is always visible in the top portion of the dialog box window To bring a page to the front when the dialog box is open click on its tab The Options menu commands open the Options dialog box with the corresponding tabbed page already on the top of the stack There are also keyboard shortcuts to some of the more frequently accessed tabs Options Menu gt All Options Keyboard Command Alt 0 Opens the Options dialog box with the last tab used on top any tab may be selected any time the Options dialog box is open Calibrate Options Menu gt Calibrate The Calibrate tab of the Options dialog box is used to calibrate multiple files to a single amplitude magnitude reference This feature helps to simplify comparison of two files and can be used to calibrate measurements stored in files to some external reference for analysis or comparison purposes There are three basic calibration options e Calibrate to Current File Sets the 0 dB point for all frequency based displays Time Slice Frequency S
3. Sets the Time Slice plot to octave band resolution e Octave Sets the Time Slice plot to 1 3 octave band resolution Amplitude Range e Max Sets the upper end of the displayed magnitude y axis range of the plot e Min Sets the lower end of the displayed magnitude y axis range of the plot Frequency Slice Frequency Scale e Linear Displays the Frequency Slice plot using linear frequency scaling e Log Displays the Frequency Slice plot using logarithmic frequency scaling e 1 3 Octave Displays the Frequency Slice plot using 1 3 octave frequency scaling e Octave Displays the Frequency Slice plot using octave band frequency scaling Amplitude Range e Max Sets the upper end of the displayed magnitude y axis range of the Frequency Slice plot e Min Sets the lower end of the displayed magnitude y axis range of the Frequency Slice plot SIA Smaart Acoustic Tools Version 4 User Guide Page 95 Chapter 3 Analysis Module Functions and Commands Spectrograph Options Menu gt Spectrograph The Spectrograph tab of the Options dialog box contains a number of options that control the appearance and behavior of the Spectrograph display Bar Width The Spectrograph is made up of vertical bars representing each FFT frame that falls within the displayed time range The vertical bars are divided into sections represent ing individual FFT data points The following options control the way these i
4. Click drag in Waveform Display to select range Click off plot in Waveform Display to clear zoom Not all keyboard commands are active in all display modes Keyboard accelerators are a subset of the menu commands Please refer to Analysis Module Commands beginning on page 68 for complete command descriptions SIA Smaart Acoustic Tools Version 4 User Guide Page 105 Chapter 4 Reference This section is intended to present real world definitions of some of the basic concepts and terminology used by SIA Smaart software products The definitions given here are accurate with regard to SIA Smaart but should not necessarily be considered comprehensive or mathematically complete We have provided a list of reference titles at the end of the section for those who wish to find a more in depth treatment of the topics discussed here Percentage Articulation Loss of Consonants ALCons This index was traditionally measured using long word lists and a set of listener scoring tables The ALCons value can be calculated from the impulse response or energy time curve two ways using either a long or short method The long form calculation includes the ambient noise condition The short form calculation does not The ALCons calculation particularly the short form calculation which ignores noise conditions tends to give results that are very generous compared to more rigorous standards such as STI ALCons values between 0 and 4 0 are c
5. Moves the selected FFT center point to the left by one pixel or one data point depend ing on the display magnification Clear FFT Center View Menu gt Cursor gt Move FFT Center Right Keyboard Command Ctrl X Clears the FFT center point selection from the Time Display and resets the default starting point for the Transform routine the first sample in the wave file Setting the FFT Center Point Using Your Mouse You can also set move the center point for the first FFT frame to any point on the Time Display plot by holding down the Ctrl key while clicking on the plot with your mouse Notes There must be enough samples between the beginning of the file and the selected FFT center point for the first half of the FFT If the selected center point would cause the first FFT to overrun the beginning of the wave file the program will default back to beginning the first FFT on the first sample in the wave file when the file is trans formed The FFT center point can only be set changed in Time Display mode Page 86 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands Change Z Order View Menu gt Change Z Order Top Trace C Keyboard Command Ctrl F Cycles through the z axis stacking order of all displayed traces In other words when multiple traces are displayed repeating this command will bring each trace in turn to the top of the stack
6. to be contaminated by persistent extraneous noise sources such as fluorescent lights or electric motors Masking is applied in Frequency Slice mode but the effects of the mask are also visible on the Spectrograph plot when Masking is on To create a mask in Frequency Slice mode first select Narrowband resolution and press Ctrl M or select Use Mask under Masking in the View menu to activate Masking With the mouse click and drag from left to right to draw a horizontal line across the frequency range you wish to mask at the highest magnitude you want to allow for those frequencies When you release the mouse button you should immediately see the effect of the mask Repeat this process for any other frequencies you wish to mask You can add more frequencies to the mask at any time using the same procedure The mask is kept in memory until you clear it using the Clear Mask command or exit the Analysis module SIA Smaart Acoustic Tools Version 4 User Guide Page 103 Analysis Module Keyboard Shortcuts The following is a list of the Analysis module s keyboard accelerators or hot keys While there are alternate ways of accessing virtually all of these functions learning the keyboard accelerators can significantly speed your work if you use the Analysis module extensively Key names on the list below are enclosed in brackets to differentiate them from descriptive text Some commands use more than one keystroke for
7. 22050 Hz 1024 21 5 Hz 11025 Hz 4096 2 6 Hz Increasing the FFT size or decreasing the sampling rate will increase the frequency resolution Notice that both of these actions increase the time it takes to collect a group of samples This is the real key to increasing frequency resolution Note A linear distribution of FFT points where there is one point every n Hertz yields much better resolution at higher frequencies than at lower frequencies In octave or fractional octave band display modes the Analysis module will display low bands for which the frequency resolution is insufficient to resolve the band s frequency data as ghosted Impulse Response You could think of the impulse response as the signature of a system e g a room and or electroacoustic system For our purposes we can define the impulse re sponse as the signal that describes the changes a test signal undergoes as it passes through a device or system under test The broadband impulse response contains a wealth of information about the system including the delay through the system frequency response reflections reverberation and decay In fact it is actually possible to use the impulse response as a filter to convolve a dry signal such as speech or music and hear what it would sound like if actually played through the same system Page 110 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 4 Reference Linear and Logarithmic
8. Ctrl key is depressed the plot will zoom in on both the x and y axes by a preset increment centered on the cursor location Clicking and dragging holding down the left mouse button while moving the mouse while holding down the Ctrl key will draw a rubber band box on the plot When the mouse button is then released the area enclosed by the box will be expanded to the full x and y limits of the plot Y When you press the Ctrl and Shift keys simultaneously the mouse cursor changes M toa magnifying glass with a minus sign in the center If you click on the plot while the Ctrl is depressed the plot will zoom out on both the x and y axes by a preset incre ment centered on the cursor location To reset the time x axis range of the plot to the full time range of the wave file and the amplitude y axis range to the default range as specified on the Graph tab of the Options dialog box click once with your mouse anywhere in the margins of the plot or press the Home key About Intelligibility Module Filters Filter Set 1 3 Octave I hd All filtering in the SIA Intelligibility module is performed in the time domain The program comes with a set of 1 and 1 3 octave digital FIR filters Filter sets are selected using the Filter Set spinner to the right of the main plot The passband is then selected from the Band spinner shown below or using the Band list box in the Intelligibility dialog window The individual ban
9. Overlapping FFT frames are analogous to shingles on a roof When overlap is set to zero each new FFT frame begins where the last one stopped like beads on a string Parametric Equalizer Equalizers are devices with one or more filters that affect the frequency content of a signal On a parametric equalizers the parameters of the filter s including gain or attenuation frequency and bandwidth are user adjustable Phase Shift A timing difference in a signal relative to some reference at one or more frequencies typically expressed in degrees Pink Noise A random or pseudorandom signal in which over a given averaging period each Octave band has an equal amount of energy Propagation Delay The time it takes for sound to travel from one place typically a loudspeaker to another place typically a microphone Reverberation Time The amount of time required for audio energy introduced into a system typically a room to diminish or decay a specified number of decibels Often expressed as an RT60 value RT60 Reverberation time The amount of time required for a system typically a room to decay 60 decibels see Decay Rate Sampling Rate The number of points per second used in the analog to digital conversion process Typically expressed in Hertz Spectrograph A three dimensional plot displayed in two dimensions with color representing the third dimension or z axis The spectrograph is a topographical representation of the
10. The Analysis module calculates frequency domain data for the waveform file using a series of Fast Fourier Transform FFT calculations The Transform command calls the Transform Waveform File dialog box prompting you to select FFT Size Overlap and Data Window parameters and enter a text Comment if you wish SIA Smaart Acoustic Tools Version 4 User Guide Page 71 Chapter 3 Analysis Module Functions and Commands Selecting Transform Parameters Selecting an appropriate FFT size Overlap and Data Window can sometimes require some trial and error The FFT size is the number of time domain samples to include in each FFT The combination of the FFT size selected and the wave file s sampling rate determine the frequency resolution of the FFTs the number of Hertz between each FFT data point The frequency resolution for the currently selected FFT size is shown to the right of the Size selector in the FFT Parameters section of the dialog box FR n Hz Larger FFT sizes yield better frequency resolution but can sometimes hide important changes in the data due to the longer amount of time encompassed by the FFT Overlapping acts to smooth the data often providing the Spectrograph with clearer information Note that overlapping data increases the number of FFT calculations and therefore the time required to create and display the frequency domain data Overlap is specified as the percentage of data each FFT shares with the previous one Dat
11. View Menu gt File 2 gt Reset to No Shift Keyboard Command Ctrl R Clears all time offset adjustment Page 84 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands Cursor Track Data View Menu gt Cursor gt Track Data With this option selected the tracking cursor snaps to the top trace in the Z order see below moving from data point to data point along the trace as you move the mouse from left to right Move Left Right View Menu gt Cursor gt Move Left Right Keyboard Commands Move Left Alt Left Arrow Move Right Alt Right Arrow When the Track Data see above is enabled the Cursor Move Left and Move Right commands can be used to move the precision tracking cursor to the right or left by one pixel or one sample or data point depending on the display mode and magnification Set FFT Center to Peak View Menu gt Cursor gt Set FFT Center to Peak Keyboard Command Ctrl Alt P The Set FFT Center to Peak command sets the center point for the first FFT frame to be calculated by the Transform routine to the highest peak found in the wave file A marker will appear on the plot and in the Waveform Display to indicate the location of the specified center point The marker is initially a red and white striped line that changes to a solid red line after the file has been re transformed Normally the Analysis module s Tran
12. cost effective set of tools for measuring and analyzing room acoustics and evaluating sound system intelligibility The package consists of two program modules the Intelligibility module and the Analysis module The Intelligibility module allows you to measure the impulse response of a device or room system and calculate both quanitative acoustical values for room analysis and objective intelligibility ratings for electro acoustic systems The Analysis module is the a file based signal analysis program that provides both time and frequency based displays of wave file data Both programs work with standard Windows audio waveform files also called wave or wav files and are designed primarily for use with impulse response data The SIA Smaart Intelligibility Module The Intelligibility module can calculate several objective speech intelligibility indices and quantitative acoustical values from impulse response data store in Windows wave files The Percentage of Articulation Loss of Consonants ALCons Clarity early to late energy ratio for some number of milliseconds e g C50 C35 or C7 and both Speech Transmission Index and Rapid Speech Transmission Index STI and RSTI can all be calculated from the impulse response The Intelligibility module can also be used to find delay times and reflections and calculate Early Decay Time EDT Direct to Reverberant level and RT60 from the same impulse response data The program includes its own i
13. decay rate of a room first published by Manfred Schroeder Before personal comput ers were powerful enough to calculate the actual impulse response of a system using techniques such as MILS or a dual FFT transfer function Schroeder et al suggested that a way to make measurements of reverberant decay in large halls was to use an impulsive source record the data using a strip chart recorder and integrate the decay by summing the energy starting at infinity and working backward in time Speech Transmission Index STI and RSTI This type of measurement is based on the assumption that human speech is essen tially a fundamental waveform modulated by low frequency signals STI uses the Modulation Transfer Function MTF for several octave bands to try and predict the ability of a system to convey spoken information The MTF can be measured using a special speech like amplitude modulated test signal or calculated from the broadband system impulse response the SIA Intelligibility module uses the latter method STI is expressed as a value between 0 and 1 where 0 means completely unintelligible and 1 means perfect intelligibility STI values above 0 7 are considered good to excellent Values from 0 45 to 0 7 are fair and values below 0 45 are poor The Rapid Speech Transmission Index RSTI is a shorter version of the STI calculation that uses data from just the 500 Hz and 2000 Hz octave bands RSTI tends to yield slightly higher numbers then th
14. gt Save Difference As In Time Display and Frequency Slice modes the ASCII Save command creates a standard ASCII text file from the data displayed on the plot ASCII output files have a header with the creation date and information about the wave file followed by time or frequency domain data depending on the display mode in use in numeric form e ASCII files created in Time Display mode have a single column of amplitude values for each displayed time domain sample e ASCII files created in Frequency Slice display mode are formatted as a five column table with information about each data point in the FFT frame currently displayed After converting the data to ASCII format the Analysis Module opens a Save As file dialog box In the dialog box select a destination folder and enter a name for the text file You can also enter comment text to be included in the file header if you like Notes When two files are loaded only the one currently displayed in front is exported In Time Display mode the Time Zoom feature can be used to select just a portion of the wave file for export If you are zoomed in on the time axis only the samples within the displayed time range are exported Transform File Menu gt Transform Transform Keyboard Command Ctrl T The Analysis module requires the time domain data contained in waveform files to be transformed into the frequency domain before many of it s features can be accessed
15. sent the arrival of direct sound The Lr and Ln markers must be positioned manually Any of the markers can be moved anywhere on the plot using your mouse The time and amplitude position milliseconds dB for each marker are displayed in the marker coordinate readout fields above the plot To calculate intelligibility values other than STI and RSTI from an impulse response first confirm that the Ld marker is in the correct position If it has been moved since the file was opened or the position is otherwise incorrect click the Set LD to Peak to return it to the highest peak in the impulse response or manually move it to the top of the first arrival peak by dragging the marker with your mouse The Lr marker should then be positioned at the top of the reverberant decay slope sometimes called the elbow or knee of the impulse response and the Ln and the Ln marker at the approximate point where the decay slope meets the noise floor sometimes referred to as the saddle You will need to repeat this procedure for each octave or 1 3 octave band you intend to analyze The Intelligibility module remembers the marker positions for each passband during run time and will return the makers to the correct position for each band as you switch between bands during a session Please note that the marker positions are not stored when the file is closed SIA Smaart Acoustic Tools Version 4 User Guide Page 11 Chapter 2 Intelligibil
16. 02 A eoero By Room2 wav ios eree Pee soo menginu The Frequency Slice shows EE A Time Slice eSe Spectra Freq Slice Options magnitude y axis versus frequency x axis for a given frame in effect a still frame spectrum analyzer The FFT data may be displayed in Linear Logarithmic Octave or 1 3 Octave frequency ES scaling The highest magni Fee tude value found in all the FFT frames calculated for the wave file is regarded as 0 dB All other magnitude values on the Frequency Slice plot are given relative to this 0 dB point er rer 0 750 Tagg matom Power Sp ary i Frequency Scale Magnitude dB iale ag e 4 2 3 4 perau In Frequency Slice mode you can step through each of the FFT frames calculated for the file using the Next Slice and Previous Slice commands under Slice in the View menu SpaceBar or Shift SpaceBar on your keyboard or using the Frame spinner that appears to the right of the plot in Frequency Slice mode Also because each FFT frame represents a different time location the Time Zoom pan controls the Left and Right arrow keys can be used in this mode to step through slices 1 0 02 sec Im xi Frame locator bars in the provide a visual reference for the time position of the data from which the currently displayed FFT was calculated Selecting Go To Slice under Slice in the View menu or clicking the Fr
17. Analysis modules may contain information not included in the manual Your copy of Smaart Acoustic Tools may also include a file called Readme doc located in the main program folder with additional information about the software The default location for the Acoustic Tools program folder is C Program Files SIA Smaart Acoustic Tools Technical Support Support for SIA software products is available through our web site by e mail or by telephone On the SIA web site www siasoft com you can find Application Notes Case Studies and answers to frequently asked questions as well as product news updates and an on line web support forum Maintenance updates and information of interest to SIA Smaart users is posted on the web site as it becomes available For technical support via e mail the address is support Osiasoft com The telephone number for SIA technical support in the USA is 508 234 9877 SIA Smaart Acoustic Tools Version 4 User Guide Page 125 Index Symbols ALCons 13 106 1 3 Octave Band Filters 46 A About Intelligibility Module Filters 25 About Sound Hardware 1 Absolute Value 115 All Bands Table 38 All Options 47 48 49 50 52 Amplitude 43 79 115 Decibel Scale 43 Linear Scale 43 Amplitude Range 49 Analog to Digital A D Conversion 115 Analysis Module Commands See Analysis Module Commands Mouse Procedures 100 FFT Frame Selection 100 Frequency Masking 102 Select Change Normalization Point 101 Tim
18. Calculating Intelligibility 10 Calibrate 89 Calibrate 0 dB 98 99 Change Z Order 87 Channel 46 78 Clarity 13 115 Clarity C n 49 Clarity Factor 50 Clarity Factor Cn 106 Clear FFT Center 86 Clear Mask 84 Close File 1 68 Close File 2 69 Coherence 115 Color 47 89 Color Options 47 Color Schemes 90 Colors 96 Commands 68 Compressors 115 Configuration 39 73 Export 73 Import 73 Configuring Windows Audio Controls 122 Create Impulse From File 34 36 38 39 Crosstalk 115 Cursor 85 86 87 88 89 Track Nearest Data Point 46 D Data Window 115 Data Window Functions 107 Decay Rate 115 Decibel 116 Decibels 107 Default Zoom 87 Devices 48 91 Devices Options 48 Direct to Reverb 13 37 Direct to Reverberant Level 108 Dual FFT 15 20 34 Dual FFT Measurement Setup 20 Dual FFT Recording the Impulse Response 23 Dual FFT Setting Measurement Parameters 21 Dynamic Range 116 E Early Decay Time 13 37 Early Decay Time EDT 116 Energy Time Curve ETC 108 ETC 44 108 Exit 74 External Hardware 3 Measurement Microphone 3 Mixer or other level adjustment device 3 F Fast Fourier Transform FFT 109 FFT 15 20 34 109 116 FFT size 32 FFT Center Point 86 Clear 86 Move 86 Select Change 101 Set FFT Center to Peak 85 86 FFT Frame Selection 100 SIA Smaart Acoustic Tools Version 4 User Guide Page 127 FFT Time Constant 32 Figures Dual FFT Measurement Setup External Signal Source 21 In
19. Commands File 2 Shift Ctrl L Close File 2 Shift Ctrl 0 Open File 2 Ctrl F Change Z Order Ctrl R Reset to No Shift clear time offset Ctrl Left Arrow Move File 2 Left negative time offset fine adjust Ctrl Right Arrow Move File 2 Right positive time offset fine adjust Shift Ctrl Left Arrow Move Left Fast negative time offset coarse adjust Shift Ctrl Right Arrow Move Right Fast positive time offset coarse adjust Frequency 1 Select Frequency Zoom Range 1 2 Select Frequency Zoom Range 2 3 Select Frequency Zoom Range 3 4 Select Frequency Zoom Range 4 5 Narrowband Frequency Banding 6 Narrowband Linear Frequency Scaling 7 Narrowband Log Frequency Scaling 8 Octave Frequency Scaling Banding 9 1 3 Octave Scaling Banding Notes Mask Ctrl M Enable Disable Masking Shift Ctrl M Clear Mask Options Alt 0 Options Alt S Spectrograph Options Alt Z Zoom Options Slice SpaceBar Next Slice Shift SpaceBar Previous Slice Ctrl G Go To Slice Frequency Slice only Mouse Shortcut Click in Waveform Display Time Zoom Up Arrow Time zoom out Down Arrow Time zoom in Left Arrow Move Time Range Left Right Arrow Move Time Range Right Shift Up Arrow Default Zoom zoom out to full time scale Mouse Shortcuts
20. Copy To dialog box navigate to the folder where you want to put the file type a file name and click the Save button Note All SIA Smaart applications let you set up your own display and printing Color Schemes This feature can be very useful when working with screen shots For example you can set up a Color Scheme with white as the background color and dark traces to optimize the captured image for printing to a black and white printer Co or Schemes are accessible through the Colors tab of the Options dialog box in both the Intelligibility and Analysis Page 28 SIA Smaart Acoustic Tools Version 4 User Guide Intelligibility Module Commands File Menu Commands Open File Menu gt Open Keyboard Command Ctrl 0 ne Room way Pes a 000 EAS Clicking the File button in the upper left corner of the main Intelligibility module window or selecting Open from the File menu calls the Open file dialog box allowing you to select standard Windows audio waveform wav file also called a wave file to be opened for analysis Note that the standard Windows dialog box that has been modified to show the sampling rate resolution 8 24 bits sample type stereo or monaural and the length in samples and seconds of the file you select If a stereo file is loaded only one channel is displayed You can switch between channels using the L and A left right channel selector buttons to the right of the file name and information
21. File 2 Keyboard Command Ctrl Shift L Closes File 2 File 1 remains open File Info File Menu gt File Info Opens the File Information dialog box This dialog box gives you the following informa tion about the file s currently open in the Analysis Module e Sampling rate e Sampling Resolution 8 to 24 bit e File type stereo or mono e The name of each file e The length of each file in samples and seconds e The text comment in the sia file created when the wave file is transformed if applicable When two files are loaded the Shift field displays the time offset in samples for File 2 You can adjust the offset by typing in a new value in this field The time offset for File 2 can also be changed using menu keyboard or mouse commands Please refer to File 2 View menu commands on page 84 for more information SIA Smaart Acoustic Tools Version 4 User Guide Page 69 Chapter 3 Analysis Module Functions and Commands Intelligibility File Menu gt Intelligibility Intelligibility This command opens the SIA Smaart Intelligibility module automatically loading the same wave file currently that is open in the Analysis Module Since neither program normally alters the wave file in any way it is not a problem for the two programs to have the same file open at the same time For more information about the Intelligibility module please refer to Chapter 2 of this manual beginning on page 6 Save Wave
22. Fourier Transform and its Applications Englewood Cliffs Prentice Hall Inc 1988 Davis D amp Davis C Sound System Engineering Second Edition Indianapolis Howard W Sams amp Co 1987 Digital Signal Processing Committee ed Selected Papers in Digital Signal Process ing Il IEEE Press Selected Reprint Series New York IEEE Press 1975 Digital Signal Processing Committee ed Programs for Digital Signal Processing EEE Press Selected Reprint Series New York IEEE Press 1979 Giddings P Audio System Design and Installation Indianapolis Howard W Sams Co 1990 Harris H J On the Use of Windows for Harmonic Analysis with the discrete Fourier Transform Proceedings of the IEEE Vol 66 No 1 pp 51 83 January 1978 Knudson V 0 Harris C M Acoustical Designing in Architecture New York John Wiley and Sons Inc 1950 reissued by the American Institute of Physics for the Acoustical Society of America New York 1978 Olson H F Acoustical Engineering Princeton Van Nostrand 1957 reissued by Professional Audio Journals Philadelphia 1991 Olson H F Music Physics and Engineering New York Dover Publications 1967 Page 118 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 4 Reference Oppenheim A V ed Applications of Digital Signal Processing Englewood Cliffs Prentice Hall Inc 1978 Oppenheim A V Schafer R Digital Signal Processing Englewood Cl
23. Information dialog A standard Windows Print dialog box will then open to allow you to select a printer and set up your printer options before sending the document to print Note If you un check either the Show custom print dialog before print and print preview check box on the Printing tab of the Options dialog box or the check box labeled Show this dialog before print and print preview in the Custom Print Informa tion dialog box both the Print and Print Preview commands see next page will bypass the Custom Print Information dialog box and take you directly to the Print dialog box SIA Smaart Acoustic Tools Version 4 User Guide Page 39 Chapter 2 Intelligibility Module Functions and Commands Print Preview File Menu gt Print Preview The Print Preview command first takes you to the Custom Print Information dialog box to allow you to set title text and other options for the printout before proceeding When you click the OK button in the Custom Print Information dialog box the Intelligi bility goes to Print Preview mode to show you what you see is what you get WYSIWYG preview of how the printed page should look You can then use the Print button to send the document to the currently selected printer immediately and exit Print Preview mode or select Close to return to the normal Intelligibility module program window without printing the document Print Setup File Menu gt Print Setup The Print Setup comma
24. Latency The delay through a given unit or system Latency is often referred to as the throughput delay of a device It is typical for digital delays to have a small latency even when they are set to zero time delay Linear Scale The term linear refers to a set of values or scale of a graph on which values are evenly spaced On a linear scale each value or unit has equal dimension Logarithmic Scale A scale where each power of a given number e g ten is given equal dimension Magnitude A number assigned to a quantity so that it may be compared with other quantities For complex quantities the magnitude is the square root of the sum of the squares of the real and imaginary parts Nyquist Frequency In digital audio the Nyquist frequency is one half of the sam pling rate The Nyquist frequency represents the highest frequency contained within a signal sampled at a given sampling rate Octave Band Resolution Octave band resolution combines all data points in a given octave and displays a total energy value for each octave band as opposed to a linear or logarithmic narrowband displays that plot the value of individual FFT data points Standard octaves are centered on 16 31 5 63 125 250 500 et al Hertz Page 116 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 4 Reference Overlap For the purposes of SIA Smaart overlap refers to the amount of data each successive FFT Frame shares in common with the one before
25. Open Volume Control double click the speaker icon shown above on the Windows Taskbar or click the Start button and select Programs gt Accessories gt Multimedia gt Volume Control e Inthe Volume Control application select Properties from the Options menu e Click the Recording radio button make sure the boxes for Microphone and Line In are checked in the list below and click OK to exit the Properties dialog box Notice that the title of the Volume Control window changes to Recording Control Make sure the Se ect box for Line In is checked confirm that the balance control is centered and the fader is set to a useful level If your computer is equipped with an internal microphone it s a good idea to also un check the Select box under the Microphone fader before exiting the Recording Control application Input Levels It is important to maintain proper input signal levels when performing measurements of all types For best results you need a good strong signal that does not light the Clip indicators above the meters If the signal level is too low you will get a poor signal to noise ratio If it is too high the input s will overload causing clipping This will compromise the accuracy of your measurements and could damage your com puter Overloading one input channel can also cause the other to behave erratically When using a test signal with a high crest factor such as pink noise transient peaks in
26. Options dialog box provides the following controls for the appearance and behavior of the Time Display plot Amplitude Scale e Linear Displays the amplitude y axis of the Time Display plot on a linear scale e Absolute Value Displays the amplitude y axis of the Time Display plot on a linear scale with all negative values converted to positive e Decibel Displays the amplitude y axis of the Time Display plot on a logarith mic decibel scale Amplitude Range The Amplitude Range controls allow you to set both the Current and Default amplitude range to be displayed on the Time Display plot e Max Sets the upper end of the displayed amplitude y axis range of the plot e Min Sets the lower end of the displayed amplitude y axis range of the plot Show Delta Cursor In Time values in the Analysis module can be displayed in any combination of time samples or distance equivalents depending on which of the following four options is selected e Time Displays the horizontal difference in seconds e Feet Displays the horizontal difference in feet e Meters Displays the horizontal difference in meters e Samples Displays the horizontal difference in samples Speed of Sound The Analysis module uses the Speed of Sound setting to calculate distance equivalents for time values The speed of sound value can be specified in either feet or meters depending on which unit of measure is selected see ab
27. Readout This field gives you x and y axis along with z in Spectrograph mode coordinates for the Analysis module s precision tracking cursor when the mouse cursor is positioned over the main plot area or the Waveform display Coordinates are given in seconds dB amplitude percentage or Hertz as appropriate for the display type Page 56 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands Relative Cursor Readout 0 5753 sec 644 4 28 78 dB In Time Display and Time Slice modes you can use your mouse cursor find the time and amplitude magnitude difference between two points in the main display by holding down the left mouse button and drawing a line on the plot The line you draw remains visible on the plot when you release the mouse button and the difference between the line s end points are displayed in this field In Time Slice mode only the decay slope in decibels per second and equivalent RT60 value are also calculated and displayed here See Delta Decay Rate Calculation on page 102 for more details The Waveform Display 38 6 0 000 0 250 0 500 0 750 1 000 The Waveform Display located above the Plot Area is a simple time domain repre sentation of the waveform wav file s open in the Analysis module This display serves as a visual locator for the data being displayed main Plot Area In Time Display Time Slice and Spectrograph modes locator bars in the Waveform Di
28. Save button that allows you to export the values to an ASCII file for import into other applications or documents Both can also be printed directly from the Intelligibility module Page 12 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands The Intelligibility Graph Intelligibility Clicking the ntelligibility button opens the Intelligibility dialog box This window displays the results intelligibility calculations and several quantitative acoustical values With the exception of STl and RSTI all of the values displayed in this window apply only to the passband currently displayed in the main program window Intelligibility D Program Files SIA Smaart Acoustic Tools Waves E BAD POOR FAIR GOOD EXCELLENT Alcons H T T T T T T T SAO 35 195 NS 65 38 22 13 SSS ye E EA A stl H T T T T T 7 T 02 03 04 05 06 07 08 09 10 RT60 f 1 28 Sec Clarity 35 ms Band Early Decay Time 0 41 Sec STI I 0 72 2kHz EZ Direct to Reverb 27 dB RSTI 0 64 sue The Intelligibility dialog window is mode less meaning you can leave it open while you continue to work in the main program window When you move the marker positions on the main plot values displayed in the Intelligibility dialog window update themselves automatically where applicable to reflect changes as they are made All of the information shown in the Intelligibility graph window can be s
29. The unit of measure selected here also determines whether distance equivalents are displayed in feet or meters elsewhere in the program The default speed of sound value is 1120 feet per second or 341 359 meters per second SIA Smaart Acoustic Tools Version 4 User Guide Page 49 Chapter 2 Intelligibility Module Functions and Commands Time Range The controls in Time Range section set the current x axis range for the main plot in milliseconds The default time range is always the full length of the wave file and the time scale is always linear Note that the current displayed time range for the plot can also be set using the Zoom X In Out and Move Range Left Right commands or by using your mouse to zoom in and out Save Filter Data in Memory When this box is checked filtered versions of the wave file data are held in memory after they are calculated so that you can switch between previously calculated passband views almost instantly This is particularly useful when you are looking at the lowest octave or 1 3 octave passbands where the calculation time for filtering can be significant even on a very fast machine You will probably want to leave this box checked unless your computer has very limited system resources available and you need to minimize the amount of memory the Intelligibility module requires Clarity This value specified in milliseconds determines the Clarity Factor dis played in the Intelligibility Graph and in t
30. a new version of Windows from a previous version you will probably need to obtain updated drivers for your sound hardware from the sound card or computer manufacturer as well It is not uncommon for manufacturers to discover device driver software problems after a card or computer ships If you are sure your hardware and software drivers are properly configured and you continue to experience problems contact the sound hardware or computer manufacturer In many cases you can obtain updated driver software that will correct the problem s If your computer has more than one sound hardware and or MIDI I 0 device or driver set installed make sure the proper devices are selected for both audio and MIDI l O on the Devices tab of the Options dialog box accessible from the Options menu in both the Intelligibility and Analysis modules SIA Smaart Acoustic Tools Version 4 User Guide Page 121 Appendix A Troubleshooting Configuring Windows Audio Controls Se 7 28PM Beginning in Windows 95 the Windows Volume Control application provides a standardized interface for controlling the audio inputs and outputs of many or most Windows compatible audio devices If you have trouble getting a signal into either SIA Smaart Acoustic Tools program module from the computer s line in inputs or suspect the computer s internal microphone may be enabled and contaminating your measurements use the following procedure to access the Record input controls e
31. access by clicking the Properties button in the Print Setup dialog File Menu gt Exit Keyboard Command Alt F4 Ends your SIA Smaart Analysis module session and returns you to the Windows desktop Page 74 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands Audio Menu Commands Rec Play Pause Stop l Record Audio Menu gt Record The Record command opens the Record Wave File dialog box This dialog box is a simple wave file recording control panel To record a new wave file on your computer s hard disk e Entera name for the new file in the Output File field The Browse button calls a standard Windows Open file dialog box allowing you to select the destination folder directory for the file Enable the Stereo check box if you want to record a stereo wave file Check the level of the signal s coming into the sound card inputs on the input level meters the right channel meter is only active if the Stereo check box is enabled If the clip indicators light this indicates that the input signal is overloading the sound card inputs and should be adjusted before recording Select the sampling rate This determines frequency content of the wave file 44 1 k or 48 k is required for full bandwidth audio 22050 is sufficient for speech Select the Bits per sample the digital resolution 16 bit resolution is recom mended for most applications Click the Re
32. access nearly any associated parameter or option you are likely to need for all but the most advanced features Readouts have been enlarged and where appropriate the text is color coded to match the associated trace color This helps make it easier to understand at a glace exactly what you are seeing The following is a brief description of the basic elements that make up the Analysis module program window Detailed information on Analysis module displays and functions can be found in Analysis Module Functions beginning on page 59 Page 54 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands The Menu Bar File Audio Wiew Options Help Virtually all of the program functions that are available as on screen controls and or keyboard commands are also accessible through the pull down menus on the Menu Bar Menu commands also provide access to many less commonly used features To activate a pull down menu from the Menu Bar click on its name using your mouse or hold down the Alt key while pressing the key corresponding to the underscored letter in the menu name When a menu is open commands may be selected by clicking on their names with your mouse or by typing the underscored letter Menu commands followed by ellipses three periods call dialog boxes An arrow head at the right of a menu item indicates that this command activates a nested fly out submenu For explanations of Analysis
33. can play an important part in overall system intelligibility There is no real benchmark for this value other than that higher numbers are better Energy Time Curve ETC The ETC is the envelope of the decay of a system The ETC is mostly used to look at reflections and decay rates of a system s response The ETC is similar in some ways to the SIA Smaart Analysis module s Time Slice display however the ETC is calcu lated by using the Hilbert transform on the time domain impulse response data whereas the Time Slice is calculated using a frequency domain representation of a system s impulse response Page 108 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 4 Reference Fast Fourier Transform FFT The Fast Fourier Transform FFT is a special case of the Fourier Transform a math ematical technique used to transform time domain data into frequency domain data The output of the transform is a set of complex numbers representing both frequency and phase information about the original time series The term Fast Fourier Transform comes from the fact that if you specify the time domain data to contain a power of 2 samples the transformation can be calculated very quickly by digital computers Powers of 2 are the values of 2 where n is an integer 1 2 3 etc Examples ifn is the power of 2 2 is 8 256 9 512 10 1024 11 2048 12 4096 All frequency transformations in SIA Smaart are FFTs and require the time reco
34. dB on the Input Meters and click the Record button The Intelligibility module will record audio data based on your measurement parameters process the data and write the results to the specified output file When the recording process is completed the Record Impulse dialog box closes automatically and the new file is displayed in the main Plot Area SIA Smaart Acoustic Tools Version 4 User Guide Page 23 Chapter 2 Intelligibility Module Functions and Commands Finding Time and Amplitude Differences In decibel dB amplitude scaling mode the time and amplitude difference between the Lr and Ln markers on the impulse response plot the S ope in dB second and the equivalent RT60 reverberation time are normally displayed in the slope readout and relative cursor readout fields above the plot The Intelligibility module has another feature that allows you to find this same information as well as the distance the time difference represents given the speed of sound for any two points on the plot in any display mode If you press the Shift key on your keyboard while the mouse cursor is positioned over the main plot the mouse cursor changes to a tiny pencil If you hold down the Shift key while dragging the cursor moving the mouse while holding down the left mouse button across the plot you will draw a line on the plot While the line is present on the plot the information in the Relative Cursor Readout is calculated relative to th
35. dialog before print and print preview check box on the Printing tab of the Options dialog box or the check box labeled Show this dialog before print and print preview in the Custom Print Information dialog box both the Print and Print Preview commands see next page will bypass the Custom Print Information dialog box and take you directly to the Print dialog box SIA Smaart Acoustic Tools Version 4 User Guide Page 73 Chapter 3 Analysis Module Functions and Commands Print Preview File Menu gt Print Preview The Print Preview command first takes you to the Custom Print Information dialog box to allow you to set title text and other options for the printout before proceeding When you click the OK button in the Custom Print Information dialog box the Analysis goes to Print Preview mode to show you what you see is what you get WYSIWYG preview of how the printed page should look You can then use the Print button to send the document to the currently selected printer immediately and exit Print Preview mode or select Close to return to the normal Intelligibility module program window without printing the document Print Setup Exit File Menu gt Print Setup The Print Setup command opens a standard Windows Print Setup dialog box where you can select a printer and set up the page size orientation and paper source for hard copy output Depending on the type of printer selected there may be additional options you can
36. dialog box If you un check this check box the Analysis module will bypass the Custom Print Information dialog box in Print and Print Preview operations and execute the selected command immediately Rainbow Options Menu gt Rainbow The Rainbow tab of the Options dialog box has the following options for the Time Slice Rainbow display feature e Center Frequency 1 side band When this option is selected the Rainbow display plots the Time Slice for the selected center frequency plus two sidebands one octave or 1 3 octave up and down from the center frequency depending on the resolution selected Narrowband resolution is not available for the Rainbow display Specific frequencies Selecting this options allows you to select three specific octave Time Slices to be displayed when the Rainbow feature is enabled Page 94 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands Slice Options Menu gt Slice The Slice tab of the Options dialog box provides the following options controlling the appearance and behavior of the Time Slice and Frequency Slice displays Time Slice e Center Frequency Sets the center frequency for the Time Slice plot the center frequency can also be changed using the Next Slice and Previous Slice com mands Frequency Scale Narrowband Sets the Time Slice plot to narrowband single FFT point resolu tion e 1 3 Octave
37. dialog box allows you to create edit and manage Color Schemes for the Analysis module program window and displays The Color Schemes section of the Colors tab has a list of all available Color Schemes along with buttons for creating editing and deleting user defined schemes A pair of list boxes below the Color Schemes section allow you to select separate color schemes for display and printing purposes Color Schemes New Clicking the New button calls the Edit Color Scheme dialog box allowing you to create anew color scheme In this dialog box you can change colors for various display elements and optionally a Windows bitmap bmp file to use as a background for the program Window Color selections initially shown in the dialog box for each element are based on the Color Scheme currently in selected in the list Edit The Edit button calls the Edit Color Scheme dialog box to allow you to edit an existing user defined Color Scheme selected in the Color Schemes list Page 90 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands Delete Clicking this button de etes the user defined Color Scheme selected in the list on the left e Display Color Scheme Selects an existing Color Scheme to be used for display purposes the colors shown on your computer screen e Printing Color Scheme Selects an existing Color Scheme for use when printing from the Analysis module D
38. different things hence much of the confusion with decibels SIA Smaart Acoustic Tools Version 4 User Guide Page 107 Chapter 4 Reference For our purposes in the context of SIA Smaart Acoustic Tools 0 dB means 1 The input and output or two inputs are equal in level for a given frequency as in a Transfer Function display or 2 The highest level that can be reached This usage applies to the Input Level Meters where a signal greater than 0 dB represents overload and the Analysis module s Spectrograph display mode where all magnitude values are represented as dB down from zero In the case of the Input Level Meters 0 dB represents a value equal to the maximum input voltage allowed by the sound cards A D converter The range of the meters is set as a negative number of decibels relative to this value Similarly the dynamic range of the Spectrograph display is specified as a negative number of dB relative to the maximum digital amplitude resolution of the waveform file Note For many sound cards the maximum A D converter input voltage is user selectable Check your sound card documentation and utilities for more information Direct to Reverberant Level This is simply the amplitude difference between the level of the direct sound and the level of the top of the reverberant decay stage of the impulse response This value is expressed in decibels and is of interest in both broadband and band limited decay curves as it
39. down the Shift key while clicking on the plot typically near a peak on one of the traces with the left mouse button When Normal ize is on two vertical white lines on the plot indicate the normalization point To move the normalization point hold down the Shift key while clicking another on the plot Pressing the N key or selecting the Normalized command from the View menu toggles normalization on and off Power Spectrum View Menu gt Power Spectrum Power Sp P Keyboard Command P In Frequency Slice mode the Power Spectrum command plots a single trace that represents the average of all or a specified range of the frames calculated for a wave file The locator bars in the Waveform display above the main plot and the FFT range over which the power spectrum was calculated is shown in the Frame Range readout to the right of the plot Frame Range The time range over which the Power Spectrum is calculated may be specified using time coordinates or FFT frame numbers on the Power Spectrum tab of the Options dialog box or by clicking the Frame Range readout to the right of the plot and entering a range of FFT frames in the pop up dialog Power Spectrum is a toggle command Repeat the command or click the Power Spectrum button again to return to the normal single FFT Frequency Slice display Note The mathematical technique used to calculate the Power Spectrum is an RMS running average of the complex frequency data
40. example the accelerator for the Transform command is Ctrl T This means you must hold down the Contro key while you press the T key For three key accelerators you would hold down the first key while pressing the third Amplitude Amplitude Y Zoom Out Amplitude Y Zoom In PgUp Move Amplitude Range Up PgDn Move Amplitude Range Down Time Display Ctrl D Decibel Amplitude Scaling Ctrl L Linear Amplitude Scaling Ctrl V Absolute Value Amplitude Scaling Ctrl Alt P Set FFT Center to Peak Ctrl Alt Left Arrow Move FFT Center Point Left Ctrl Alt Right Arrow Move FFT Center Point Right Ctrl X Clear FFT Center Ctrl Mouse click outside plot Clear FFT Center Point Selection Mouse Ctrl Clicking on Time Display plot to set move first FFT center point Audio Shift P Play wave file Cursor Alt Right Arrow Move Right Alt Left Arrow Move Left Display D Time Display F Frequency Slice S Spectrograph mode T Time Slice Mode P Power Spectrum Frequency Slice mode only R Rainbow Display Time Slice only N or Shift click on Time Slice Rainbow Display plot Normalize File Ctrl 0 Open File 1 Ctrl P Print Ctrl T Transform Page 104 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and
41. fields or the Channel commands in the View menu Save As File Menu gt Save As Keyboard Command Ctrl S This command calls a modified Windows Save As file dialog box allowing you to create a new wave wav file or a batch of files based on the wave file currently loaded in the Intelligibility module The top portion of the dialog box has the normal areas for entering a file name and selecting the target directory for the new file The lower portion of the Save As dialog box offers additional options On the lower right of the Intelligibility module s Save As dialog box is a pair of radio buttons to select whether you want the new file to include the entire time range of the original file or just the time range currently displayed on the main Intelligibility module plot On the lower left is a list box labeled Bands to Save with a listing of all available filters To the left of each entry in the Bands to Save list is a check box You can select whether to save the unfiltered Broadband data a filtered version of the original data or some combination by checking and un checking these boxes SIA Smaart Acoustic Tools Version 4 User Guide Page 29 Chapter 2 Intelligibility Module Functions and Commands When you save the unaltered broadband wave file data the name for the new file will be the file name entered on the File Name line in the upper portion of the dialog box Filtered versions are named automatically using t
42. is determined by the selected display options for the Schroeder reverse time integration curve If the Schroeder trace is not displayed the precision cursor tracks the impulse response trace by default When the Schroeder trace is present the precision cursor will track the Schroeder trace if Schroeder On Top is selected see page 44 Octave Band Filters and 1 3 Octave Band Filters View Menu gt Octave Band Filters and 1 3 Octave Band Filters Filter Set 1 3 Octave I xi These two commands are used to select the filter set used for band limited impulse response and ETC displays The selected filter set determines the choices available on the Bands spinner and the Bands list box in the Intelligibility dialog box Channel View Menu gt Channel EE When a stereo wave file is loaded only one of the two channels is displayed You will be asked to select which channel you want to display when the file is initially opened but if you want to change your selection later the Left and Right commands in the Channel submenu may be used to select either channel for display at any time Page 46 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands Options Menu Commands All Options Menu gt All Options Keyboard Command Alt 0 This command opens the Options dialog box with the last tab used on top Any tab may be selected any time the Options dialog box is open Color
43. known group of seed numbers Since the output of the system under test is compared to MLS data generated internally by the Intelligibility module it is critical that the stimulus signal matches the internally generated data precisely It is not an absolute requirement that you use the Intelligibility module s internal MLS signal generator Any two MLS stimulus signals of identical length generated at the same sampling rate and resolution using identical seed numbers should be identical And in practice most MLS generators do in fact use the same seed numbers however there is no accepted standard that says they must Using the internal MLS generator is probably the easiest way to be absolutely sure the stimulus signal and program s internal MLS reference parameters are identical SIA Smaart Acoustic Tools Version 4 User Guide Page 17 Chapter 2 Intelligibility Module Functions and Commands Microphone Loudspeaker Computer System Under Test Preamp Amplifier Phantom Power Supply External Loopback Optional The diagram above shows a typical measurement system setup for MLS measure ment Note that the use of an external loopback connecting one of the computer outputs to one of the inputs is optional The loopback is required due to a limitation in Microsoft Windows only as a time reference if you need to know the delay time through the system under test You can make an MLS measurement that is valid in of every
44. menu commands hot keys and the Options dialog box Page 6 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands The following is a brief description of the basic elements that make up the Intelligibility module program window Detailed information on Intelligibility module displays and functions can be found in ntelligibility Module Functions beginning on page 10 The section on Intelligibility Module Commands beginning on page 29 contains complete listing of all menu commands and options The Menu Bar File View Options Help Virtually all of the program functions that are available as on screen controls and or keyboard commands are also accessible through the pull down menus on the Menu Bar Menu commands also provide access to many less commonly used features To activate a pull down menu from the Menu Bar click on its name using your mouse or hold down the Alt key while pressing the key corresponding to the underscored letter in the menu name When a menu is open commands may be selected by clicking on their names with your mouse or by typing the underscored letter Menu commands followed by ellipses three periods call dialog boxes An arrow head at the right of a menu item indicates that this command activates a nested fly out submenu For explanations of Intelligibility module menu commands please refer to the Help file and manual sections titled ntelligibilit
45. options are particularly useful when comparing multiple wave files A legend area below the plot shows the number of colors used and the Dynamic Range of the Spectrograph The value of dB color is displayed to the right of the color scale bar The magnitude range represented by each color used is determined by the number of colors used and the specified dynamic range These parameters are set from the Spectrograph tab of the Options dialog box The Spectrograph may be displayed in up to 236 colors Banding MOTO E Zi The frequency range of the Spectrograph plot s y axis is set using the four user configurable Frequency Zooms The frequency y axis scale can be linear or Page 64 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands logarithmic Frequency scaling may be selected using the Banding Spinner that appears to the right of the plot in Spectrograph mode or on the Spectrograph tab of the Options dialog box Frame Range The Spectrograph plot is actually made up of vertical bars with each bar representing one FFT frame The vertical bars are divided into sections representing individual FFT data points with the magnitude for each point indicated by color By default all FFTs calculated for a wave file are displayed to show the entire time range of the file along the x axis You can select a specific time range using the Time Zoom commands by selecting a time range in the Waveform
46. other respect without a loopback When recording without a loopback the initial peak in the impulse response indicating the arrival of direct sound at the measurement microphone position will be positioned arbitrarily at 10 or 100 milliseconds depending on the MLS length ree To begin the recording process open the Intelligibility module and click the Record Rec button When the Record Impulse dialog box appears click the MLS tab at the top of the dialog box to display the MLS recording controls MLS Setting Measurement Parameters If you will be using the internal MLS generator to make your measurement set the Level control in the MLS Signal Generator section to a low number initially Set the Generate Channel s control to match the computer s line output channel you are using to send the stimulus signal to the system under test or choose Stereo to send the signal on both output channels If you are using the external loopback option the Generate Channel s will be set automatically to Stereo Page 18 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands In the Impulse Output File field you can type the path and file name for the wave file to be used to store the measurement results or click the Browse button and use the Open file dialog box to navigate to the desired folder and specify a file name If you will be using an external loopback as a time reference for the me
47. output from the internal pink noise and MLS signal generators e Wave In Bits Per Sample Sets the sampling resolution for the selected audio input recording device e Wave Out Bits Per Sample Sets the sampling resolution for the selected audio output device This setting also determines the output resolution of the internal signal generators At the bottom of the Devices tab is a check box labeled Warn before recording if the signal generator is not running Un checking this check box disables the warning message normally given if you click the Record button on either tab of the Record Impulse dialog box when the internal signal generator is not running Page 48 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands Graph Options Menu gt Graph Keyboard Command Alt G The Graph tab of the Options dialog box has the following options for controlling the appearance of the main plot and how the Intelligibility module displays data Title At the top of the Graph options tab is a text input field used to set the title line displayed above plot in the main program window and above the Intelligibility Graph in the Intelligibility dialog box Amplitude Range The Amplitude Range section has four text fields for setting the upper Max and lower Min limits of both the Current and Default amplitude y axis ranges of the main plot Note that the Current ampli
48. plot is selected using the Band spinner or the Next Slice and Previous Slice commands under Slice in the View menu The Rainbow display simultaneously plots the normal Time Slice and two sidebands By default the sidebands are 1 or 1 3 octave up and down from the center frequency depending on the selected bandwidth the Narrow Band option is not available in the Rainbow display Specific sideband frequencies can be specified on the Rainbow tab of the Options dialog box The three traces can be Normalized or aligned in amplitude at a specific time location holding down the Shift key while clicking on the plot with the left mouse button Pressing the N key toggles normalization on and off The Time Slice can be very useful for determining decay rates in a room impulse response Because it tends to be much smoother than simple time domain displays overall trends in the impulse response are easy to see You can draw a line on the Time Slice plot by holding down your left mouse button while moving the mouse cursor between the two points on the plot When you release the mouse button the decay rate in dB sec and equivalent RT60 values are displayed in the relative cursor readout immediately above the plot to the right of the standard cursor readout SIA Smaart Acoustic Tools Version 4 User Guide Page 61 Chapter 3 Analysis Module Functions and Commands The Frequency Slice Freq Slice a e Room wav Pues samples N l
49. selects the passband for both the Intelligi bility window and the main impulse response plot either the unfiltered Broadband data or a 1 or 1 3 octave passband as determined by the filter set currently in use Recording an Impulse Response MLS or Dual FFT The first decision you will need to make before recording an impulse response measurement is which recording technique to use The Intelligibility module s Record Impulse feature allows you to acquire the impulse response of a room system under test using a Maximum Length Sequence MLS or dual Fast Fourier Transform Dual FFT transfer function technique MLS and Dual FFT are basically just two different ways of comparing what goes into a system with what comes out There are however fundamental differences between the two techniques MLS is a single channel stimulus dependent measurement technique that requires the use of an internally generated MLS stimulus signal Since the stimulus signal is known only the output of the system under test needs to be recorded hence the term single channel Dual FFT is a dua channel stimulus independent measurement technique that can use virtually any continuous signal including pink noise recom mended for most acoustic intelligibility measurement applications or music as a stimulus This technique requires that you capture both the stimulus signal and the output of the system under test during the measurement procedure Each of these
50. several pieces of outboard gear may be required to make measurements in the field The following is a list of equipment you may wish to consider to complete your measurement kit Measurement Microphone We recommend the best omnidirectional micro phone with the flattest frequency response you can reasonably afford A high quality microphone preamp and an external phantom power supply are also very useful additions to a measurement tool kit Note A high quality sound pressure level meter with an audio output can be very effective as a measurement microphone Mixer or other level adjustment device Although you can set relative signal levels at the computer in many cases it is helpful to be able to adjust signal levels externally Also being able to quickly switch the signals reaching the sound card s inputs can greatly expedite the measurement process in many cases A compact mixer with quiet microphone inputs and built in phantom power is ideal as it puts several pieces of the puzzle in one box e Cables and adapters Y cables are useful for tying the measurement system into sound systems Also as most sound cards use unbalanced 2 conductor inputs several sets of adapters which allow balanced to unbalanced connections may be necessary SIA Smaart Acoustic Tools Version 4 User Guide Page 3 Chapter 1 Getting Started Installing SIA Smaart Acoustic Tools If you are familiar with the standard Windows software installat
51. the documentation that came with your printer for troubleshooting help You may need to contact your printers manufacturer to obtain an updated driver Page 124 SIA Smaart Acoustic Tools Version 4 User Guide Appendix A Troubleshooting Restoring the Default Configurations User definable options for the SIA Smaart Acoustic tools program modules are very flexible and can sometimes be confusing especially at first Both the Intelligibility and Analysis modules store the state of nearly all of these options when you exit so if a problem related to configuration does arise chances are good that it will still be there the next time you start the program Any time you wish to restore the Intelligibility module to its factory default settings select Set All Values to Default from the File menu To reset the Analysis module to its defaults select Set All Options to Default from the Options menu Resetting to defaults changes virtually user definable parameters for the program back to their original states The only exceptions are that the Color Scheme and audio input output device selections are left as set on the Co ors and Devices tabs of the Options dialog box On line Help and Readme Files If you have a problem or question about SIA Smaart Acoustic Tools and cannot find the answer in this manual check the on line Help files and Readme file if applicable The Help files accessible from the Help menus of both the Intelligibility and
52. through the Ld Lr and Ln markers Move Marker Left Keyboard Command Left Arrow Moves the selected Ld Lr or Ln marker to the left Move Marker Right Keyboard Command Right Arrow Moves the selected Ld Lr or Ln marker to the right Move Marker Up Keyboard Command Left Arrow Moves the selected Ld Lr or Ln marker upward in amplitude Move Marker Down Keyboard Command Down Arrow Moves the selected Ld Lr or Ln marker downward in amplitude Set Ld to Peak poo Keyboard Command Shift P Resets the Level direct Ld marker to the highest peak in the impulse response SIA Smaart Acoustic Tools Version 4 User Guide Page 45 Chapter 2 Intelligibility Module Functions and Commands Track Nearest Data Point View Menu gt Track Nearest Data Point The Intelligibility module features both a standard arrow mouse cursor and a precision tracking cursor The relative time and amplitude position of the precision cursor is continuously displayed on a readout above the plot The arrow cursor can always be moved freely around the plot and can be used to position the Level mark ers When Track Nearest Data Point is turned on the precision cursor snaps to the nearest data point on the top trace in the z axis stacking order while following the horizontal movement of your mouse When this feature is turned off the tracking cursor freely follows the mouse cursor The z axis stacking order
53. two approaches has its advantages SIA Smaart Acoustic Tools Version 4 User Guide Page 15 Chapter 2 Intelligibility Module Functions and Commands The MLS Method Of the two techniques MLS has the potential to offer somewhat superior noise rejection Since the MLS stimulus signal is pseudo random not random the stimulus is a precisely known quantity and may be easier to correlate with the measured system response When using MLS to acquire an impulse response the signal returned from the device or system under test is compared to the original internally generated data sequence exactly as sent to the system under test The MLS stimulus signal also has a lower crest factor than truly random noise so clipping the measure ment system s Analog to Digital A D converter is s little less of a concern Some possible disadvantages with MLS are the high concentration of energy in the top octaves and that this method is probably a little more demanding in terms of the computer s audio input output 1 0 hardware For MLS measurements the computer sound hardware needs to be capable of full duplex operation playing and recording simultaneously and it is more critical that the analog I O stages and D A and A D conversion process be as transparent as possible Since the measured signal is compared directly to the original digital MLS data it is unavoidable that some part of what you end up measuring will be the quality of the I O hardware in the
54. 3 Octave Keyboard Command 9 Changes the Frequency Slice and Time Slice displays to 1 3 octave band resolution Note If octave bands in the Frequency Slice display appear ghosted at low frequen cies it means the frequency resolution of the FFT is insufficient for the data in those bands to be completely reliable To increase frequency resolution increase the FFT size when transforming the wave file Mask The Mask feature is useful when analyzing signals known to be contaminated by persistent extraneous noise sources such as fluorescent lights electric motors etc Masking is applied in Frequency Slice mode but the effects are also visible on the Spectrograph plot when Masking is active See page 103 for more information on setting up frequency masks in the Analysis module Use Mask View Menu gt Mask gt Use Mask Keyboard Command Ctrl M To apply a mask switch to Frequency Slice mode select Narrowband resolution and select Use Mask to activate Masking With the mouse click and drag from left to right to draw a horizontal line across the frequency range you wish to mask at the highest magnitude you want to allow for those frequencies When you release the mouse button you will see the effect of the mask Repeat this process for any other frequen cies you wish to mask After a mask has been created you can add more frequencies at any time using the same procedure Repeating the Use Mask command toggles maskin
55. 3 dB SIA Smaart Acoustic Tools Version 4 User Guide Page 21 Chapter 2 Intelligibility Module Functions and Commands better signal to noise in the finished measurement however the time required to make each measurement is increased As a general rule you will want to use higher numbers of averages in noisier environments and or when you are restricted to using lower sound pressure levels to stimulate the room system under test The sampling rate SR determines the frequency content of the completed measure ment To measure the full audio spectrum a sampling rate of 44 1 k or greater is required Using lower sampling rates will restrict the highest frequency obtainable to one half of the sampling rate the Nyquist frequency The FFT size together with the sampling rate determines the FFT Time Constant also called the time window The FFT Time Constant for the selected FFT Size and SR values is automatically displayed below the FFT field To obtain a solid impulse response measurement the FFT time constant must be longer than the decay time of the system under test As a general rule an FFT time constant of 7 to 1 5 seconds is sufficient for most small to mid sized rooms Larger rooms with longer decay times require a longer time window When in doubt it never hurts to go too long in fact it will help to improve the signal to noise ratio of the measurement It does however increase both the time required to make the
56. Color dialog box allowing you to choose a standard color or specify a custom color to be used for the selected element SIA Smaart Acoustic Tools Version 4 User Guide Page 47 Chapter 2 Intelligibility Module Functions and Commands Edit The Edit button calls the Edit Color Scheme dialog box to allow you to edit an existing user defined color scheme selected in the list Note that the stock color schemes supplied with the Intelligibility module may be used as the basis for a new user defined color scheme but cannot be edited or deleted themselves Delete Clicking the Delete button deletes a user defined Color Scheme selected in the list Below the Color Scheme section are two list boxes e Display Color Scheme Selects an existing Color Scheme to be used for display purposes the colors shown on your computer screen e Printing Color Scheme Selects an existing Color Scheme for use when printing from the Intelligibility module Devices Options Menu gt Devices If your computer has more than one sound card installed the Devices tab of the Options dialog box allows you to select which of these the Intelligibility module should use This tab is also where you set the sampling resolution bits per sample for each device The Devices options tab has for drop down list fields e Wave In Selects the sound device to be used for audio input recording e Wave Out Selects the computer sound device to be used for
57. Options Menu gt Color The SIA Smaart Intelligibility module allows you to customize the colors of virtually everything on the screen and even use your own bitmap files as a background Color and background options are loaded as sets called Color Schemes Several ready to use color schemes including two with metallic bitmapped backgrounds are included with the program and you can easily define your own The Colors tab of the Options dialog box allows you to create edit and manage Color Schemes for the Intelligibility module program window and displays The Colors tab of the Options dialog box is used to create and manage color schemes for the Intelligibility Module The Color Schemes section of the Colors tab has a list of all available Color Schemes along with buttons for creating editing and deleting user defined schemes A pair of list boxes below the Color Schemes section allow you to select separate color schemes for display and printing purposes Color Schemes New Clicking the New button calls the Edit Color Scheme dialog box allowing you to create anew color scheme In this dialog box you can change colors for various display elements and optionally a Windows bitmap bmp file to use as a background for the program Window Color selections initially shown in the dialog box for each element are based on the Color Scheme currently in selected in the list Clicking any of the solid colored squares opens a standard Windows
58. SCII txt data files to many other programs automatically using their jump function The Acoustic Tools jump function is configured by a pair of text files named wrjumps txt and imjumps txt The wrjumps txt file defines jumps for the Analysis module and imjumps txt defines jumps for the Intelligibility module Both programs scan the SIA Smaart Acoustic Tools System folder on start up to look for these files If the program s jump file exists and has one or more jumps configured its jump function is enabled automatically When the jump function is enabled clicking on the Acoustic Tools logo that appears in the upper right corner of the main program window will pop up a jump menu The Acoustic Tools System folder is located in the Acoustic tools program folder The default location of this folder is c Program Files SIA Smaart Acoustic Tools System Note that wrjumps txt and imjumps txt are created automatically by the Acoustic Tools installer if SmaartLive was detected on the computer during installation and Page 26 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands you answered yes when the installer asked if you wanted to make jump modifica tions Otherwise you can easily create and or edit the wrjumps txt and mjumps txt files yourself using any ASCII text editor such as the Windows Notepad The example of a Smaart Acoustic Tools jump definition shown below would create a c
59. SIA Smaart Acoustic oole Acoustic Measurement and Analysis Software User Guide Version 4 for Windows Developed by SIA Software Company Inc An EAW Company O Copyright 2000 2001 SIA Software Company Inc All rights reserved Printed in USA This manual as well as the software described herein are furnished under license The content of this manual is furnished for informational use only and is subject to change without notice SIA Software Company Inc assumes no responsibility or liability for any errors or inaccuracies that may appear in this manual or arising from the use of the information contained in this manual or the SmaartLive software No part of this manual may be reproduced stored in any retrieval system or transmit ted in any form or by any means electronic photographic mechanical recording or otherwise without the prior written permission of SIA Software Company Inc SIA and SmaartLive are trademarks of SIA Software Company Inc SIA Smaart is a registered trademark of SIA Software Company Inc Microsoft and Windows are registered trademarks of Microsoft Corporation Intel and Pentium are regis tered trademarks of Intel Corporation JBL is a registered trademark of JBL Incorporated All other products or name brands appearing in this manual or the software described herein are registered trademarks of their respective holders Introduction SIA Smaart Acoustic Tools provides a powerful
60. Scales In SIA Smaart both time and frequency plots may be viewed using either linear or logarithmic amplitude or frequency scaling A linear scale plots the frequency or amplitude range linearly across the plot On a linear frequency scale display each unit of measure e g Hertz covers the same distance on the axis On a logarithmic frequency display each decade power of ten decibel or octave depending on the type of information displayed covers the same amount of the axis For example on a linear frequency plot covering the range or 20 Hz to 20 kHz the entire right half of the plot would be devoted to the range of 10k to 20k a single octave On a logarithmic scale each decade 10 100 100 1k 1k 10k etc would occupy an equal amount of the axis 100 to 1000 Hz a range of 900 Hertz covers the same distance on the plot as 1 kto 10k ten times the number of Hertz Both linear and logarithmic scales for frequency and amplitude have their advantages The choice of log or linear plots is based on experience and personal preference The human ear hears logarithmically in frequency however many people feel that harmonic structures and comb filters can be seen more easily on a linear display SIA Smaart Acoustic Tools allows you to switch between logarithmic and linear displays easily to find the type of plot that helps you best understand your data Maximum Length Sequence MLS A Maximum Length Sequence MLS is a type of pseud
61. This is useful for making the trace that most interests you easier to see but it is also how you assign which trace the precision cursor tracks When tracking is enabled the precision always tracks the trace that is displayed on top Default Zoom View Menu gt Default Zoom Zoom 1 2 3 4 Default Keyboard Command Shift Up Arrow Returns the both the X and Y axes of the plot to the default settings for the current display mode as defined on the Time Display Slice or Spectrograph tabs of the Options dialog box Rainbow View Menu gt Rainbow Keyboard Command R In Time Slice mode pressing the Rainbow button displays three Time Slice traces simultaneously the slice for the selected center frequency plus two sidebands By default the sidebands are one octave or 1 3 octave up and down from the center frequency depending on the resolution selected Narrowband resolution is not available for the Rainbow display Specific octave center frequencies for all three traces may be selected on the Rainbow tab of the Options dialog box SIA Smaart Acoustic Tools Version 4 User Guide Page 87 Chapter 3 Analysis Module Functions and Commands Normalized View Menu gt Normalized Keyboard Command N The Rainbow display plot can be normalized so that all three Time Slice traces have the same amplitude at a point you select To simultaneously enable Vormalized and select the normalization point hold
62. Tools The Instal Name and Serial Number must be typed exactly as they appear on the registration card Software Installation After entering your registration information the Install Wizard will guide you through the remainder of the installation process You will be prompted to choose and installa tion directory folder and given the option to install a shortcut to SmaartLive on the Windows desktop The installer will suggest c Program Files SIA Smaart Acoustic Tools as the target disk drive and folder for the Acoustic Tools program files You can accept this default or select a different destination by clicking the Browse button Page 4 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 1 Getting Started If the installer detects that SmaartLive is also installed on your computer you will be asked if you want to have jump modifications made to establish links between SmaartLive and Smaart Acoustic Tools If you answer yes it will automatically create or modify links files for all three programs to allow jumping and passing data between SmaartLive and the two Acoustic Tools program modules See Setting Up Links to Other Programs on page 26 for more information If you have previously installed the 30 day demonstration version of SmaartLive we recommend that you install the full Standard or Upgrade version of SmaartLive to the same folder used for the demonstration version This will allow the full version the overwrite
63. U Undo Redo Zoom 41 Use Loopback For Time Alignment 33 Use Mask 83 V View Menu See Analysis Module Commands Intelligibility Module Com mands W Wave In 48 91 Bits Per Sample 48 Wave Out 48 91 Bits Per Sample 48 Waveform Display Options 99 White Noise 117 Window Elements 7 Menu Bar 7 Windows Audio Controls 122 X X Zoom 17 Y Y Zoom 42 43 Z z axis 46 z order 44 46 87 Zoom 25 41 42 43 Move Range Down 42 Move Range Left 42 Move Range Right 42 Move Range Up 42 Redo 41 Undo 41 Zoom Out To Limits 41 Zoom X In 41 Zoom X Out 41 Zoom Y In 42 Zoom Y Out 42 Zoom In Out 79 Zoom Out To Limits 41 Zoom X In Out 41 Zoom Y In Out 42 Zooming With the Mouse 25 SIA Smaart Acoustic Tools Version 4 User Guide Page 131
64. U Pee A cer arene AA A Ad 93 Rain DOW parcialidad anomie 94 Mi Es 95 Spectrograph ivan AA inane 96 Time Di 98 Waveform nisnin taena a di aie 99 Set All Opti nsto Default sirrini iiaiai AE ARAARA 99 Mouse Procedur s 000 a 100 Mme Range Selection dvi 100 Select Change First FFT Center to Peak ooocccconococicnonencncnnocononnnconnononrononononcoconenoncnconenonnos 101 Select Change Normalization Point for Rainbow Dsplay cccccccccccccsccscssseseseseseeeseeeeseereeeees 101 Delta Decay Rate Calculation cccceccecceeseeeeseteeeeecseseeeeecaeseeeecaeseseeeseeseaeeesetasieeesenaneeesetaes 102 vi FFT Frame Selection in Frequency Slice Mode ccccscseseesssssssssesssesseesssessseresseseeeseerereeenenes 102 Frequency Masking cscccecsceseeseseeeeeeeeeecaeseeeecaeaeeeeecaeaeeeeecasseaeeesesasaeeesesaeieeesesasieeesetasieaeees 103 Analysis Module Keyboard Shortcuts ccccscscssecseesesesesescsessesescsenecaeaesesesatanseseeanas 104 Section 4 Reference iaa iene 106 Percentage Articulation Loss of Consonants WALCons ccocococicnonononiononocconononcnronencnnnrano 106 Clarity Factor C asai AA ias 106 Data Window Functions 0 0 cccccceseeseeeeeeeceeeeeaeseececaeseeeeecaeaceeecaeaseeeesesasaeeetesasieeetetasieaeees 107 Decibels ooo tdi ida da 107 Direct to Reverberant Level cccceesccseeseseeeseteeeeecaeseeeeecaeseeeeeceeseeeeecesasaeeesesaeieeeeesaseneeees 108 Energy Time Cu
65. Zoom As File Menu gt Save Wave Zoom As This command allows you to save just the displayed portion of the time range of a wave file loaded in the Analysis module as a new wave file After selecting a portion of an open file you wish to save using the Time Zoom commands see page 78 select this command to call the Save As file dialog box In the dialog box select or create the destination folder then enter a file name and click the Save button The new wave file is immediately loaded into the Analysis module after saving The original wave file is not altered in any way Note lf two files are loaded this command applies only to the one displayed in front Save Difference As File Menu gt Save Difference As With two files loaded this feature allows you to create a new wave file that repre sents the difference between the two Save Difference As subtracts the amplitude value of the file displayed in front sample by sample from the one in back The Change Z Order command can be used to control which file gets subtracted from which After completing its calculations the Analysis module opens a you will be prompted to select a destination folder and enter a file name for the new wave file The new file is immediately loaded into the Analysis module after saving The original files are not altered Page 70 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands ASCII Save File Menu
66. a Windows are used to reduce edge effects associated with the finite length of FFTs The Analysis Module provides several different Data Window options If you don t have another preference the default Hanning or Hamming window types generally work well The option labeled None also called a rectangular data window is typically not used After transformation the FFT size and Overlap and FFT frequency resolution in Hertz are displayed in the FFT information field at the top of the Analysis module window to right of the fields that display the number of samples resolution and sampling rate for File 1 The frequency domain data derived from the wave file data is stored ina separate file having the same name as the source wave file except that the file name extension sia is used This process is nondestructive to the wave file data and may be repeated as many times as you like The original wave file is not altered in any way The sia file is created in the same folder directory as the source wave file As long as these two files are kept together in the same folder the Analysis module will automatically find and load the existing sia file when the wav file is loaded again Page 72 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands Configuration File Menu gt Configuration The Configuration commands are used to import and export configuration files Conf
67. a portion of the wave file s full amplitude range is displayed These two commands move the displayed range up or down to allow you to view the information above or below the range currently displayed Note To reset the range of any Analysis module plot to the program defaults use the Default Zoom command see page 87 Linear Scale View Menu gt Amplitude gt Linear Scale Keyboard Command Ctrl L Sets the vertical y axis of the Time Display plot only to Linear amplitude scaling When Linear scaling selected amplitude values are given as a percentage of full scale based on sampling resolution bits per sample at which the wave file was recorded Absolute Value Scale View Menu gt Amplitude gt Linear Scale Keyboard Command Ctrl V Displays the A D amplitude values on a linear scale with all negative values converted to positive Amplitude values are given as a percentage of full scale based on sam pling resolution bits per sample at which the wave file was recorded Decibel Scale View Menu gt Amplitude gt Linear Scale Keyboard Command Ctrl D Sets the vertical y axis of the Time Display plot only to logarithmic amplitude scaling A D amplitude units are converted to decibel values Page 80 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands Slice Frame 1 0 02 sec EE xi The Slice commands are used to navigate between FFT fra
68. aart Acoustic Tools Version 4 User Guide Appendix A Troubleshooting Computer Sound Hardware Issues Windows compatible sound hardware must be present and properly configured for your system to use recording features in the SIA Smaart Intelligibility and Analysis modules SIA Smaart Acoustic Tools uses standard Windows Application Program ming Interface API calls to access the sound card and should work properly with any 100 Windows compatible audio device If the Intelligibility and or Analysis modules will not recognize your sound hardware check to see if you can record and play back wave files using the Sound Recorder and Media Player These are standard Windows utilities usually located in the Accessories section of the Programs menu accessed by clicking the Start button on the Windows Taskbar If you cannot play and record using the Sound Recorder and or the Media Player will not recognize your sound hardware check to make sure both the hardware device and the software that came with it are properly installed Sound hardware setup typically requires loading software drivers and utilities in addition to any hardware installation Depending on your system the sound hardware driver software could be on a diskette supplied with the sound card or computer the Windows setup disk s or both Some sound cards also require the user to set jumpers or DIP switches on the card itself before installation If you have upgraded your system to
69. accepted measure of intelligibility Additionally ALCons calculations are now limited to the octave band centered on 2 kHz because this is the only band in which this measurement is conventionally performed and for which the result is considered valid Contents Chapter 1 Getting Started cc escscsssescsesseseeseeseeeseeseeseeeseessessessesnsaneeaes 1 System Ha WA vain aia i i deat 1 About Sound Hardware cccccceccsesesssecseseeeeeceeseseeeceeaeseesecaeseesecaesesenecaeseseeesaeseaeeesesanseeesesaeseas 1 External Hardware cion nad tie REI Edic 3 Installing SIA Smaart Acoustic Tools cccscssccsssecsessesssesesesecseeseeseeaeeeeceeassesaeaeseseeaeasaes 4 Chapter 2 Intelligibility Module Functions and Commands sirio oido 6 Navigating in the Intelligibility Module s ssssssssessseessssssssssrsnssrenssnenssrennsnnnnnrnnnnnnnnnnnnnnnnnnnnnnennnnnna 6 The Menu Baires aeaa A E AA A EA nnaetienes 7 File Information occ necio 7 Level Marker Coordinates cccecsccseeseeeseeeeeeeeecaeseeeeecaeseeeeecaeseeeeeceeaeseeesesasieeesesaseeenesanaseee 8 Cursor Read ouit 22s A A AA A A R AA AAA EA A eas a a E E sea 8 Spe HEA OUE Euin a E E E 8 PIOCATE E oota ae Tae t ee E E EE EERE td ie ae Riles Rint ee Ria eo 9 Jump To Other Programs issia cs 9 DEALL S 9 intelligibility Module Functions ccceccsssecseeeeesseesesaeseeaeeecaeeeeaesesaeeseeeseeeeseeeeseeeaeiees 10 Calculating Intelligib
70. ame spinner displays the Go To dialog box allowing you to specify the frame you want to display by time location or FFT frame number You can also select a time location in Frequency Slice mode by clicking on the trace in the Waveform Display with your left mouse button Page 62 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands Frequency Scale Log Ne E xi The frequency x axis scaling of the Frequency Slice plot is set by the Frequency Scale spinner that appears ti the right of the plot in Frequency Slice mode The range and scale of the plot s vertical y axis may be changed using the Amplitude gt Zoom and Move commands in the View menu The amplitude range for this display can also be set from the Frequency Slice section of the Slice tab in the Options dialog box The label above the plot shows the current resolution narrowband 1 octave or 1 3 octave the frame number and the start time of the frame currently displayed Power Sp P The Power Spectrum is a special type of Frequency Slice display The Power Spec trum is a plot of the average of all or a selected range of FFT frames calculated for a wave file The power spectrum display is activated by pressing the Power Spectrum button that appears to the right of the plot in Frequency Slice mode l Frame Range When Power Spectrum is on you can also set the time range over which power spectrum is calculated by clicking
71. and Commands Frequency Zoom 1 2 3 and 4 View Menu gt Frequency gt Zoom 1 2 3 and 4 Zoom 1 2 3 4 Defaut Keyboard Commands 1 2 3 or 4 The numbered Frequency Zoom commands are used to select from the four preset frequency ranges for the Frequency Slice and Spectrograph display modes The range of each Zoom is user definable and is set from the Zooms tab of the Options dialog box The frequency sca e commands below set the type of frequency scaling used on Frequency Slice and Spectrograph plots and as the resolution bandwidth of the Time Slice display Narrowband View Menu gt Frequency gt Narrowband Keyboard Command 5 Sets the Time Slice display to Narrowband single FFT bin resolution Linear Narrowband View Menu gt Frequency gt Linear Narrowband Keyboard Command 6 Plots the frequency axis of the Frequency Slice and Spectrograph displays in Linear frequency scaling Logarithmic Narrowband View Menu gt Frequency gt Logarithmic Narrowband Keyboard Command 7 Plots the frequency axis of the Frequency Slice and Spectrograph displays using Logarithmic frequency scaling Page 82 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands Octave View Menu gt Frequency gt Octave Keyboard Command 8 Changes the Frequency Slice and Time Slice displays to octave band resolution 1 3 Octave View Menu gt Frequency gt 1
72. ange Down Page Down When you are zoomed in on the vertical y axis range of the main plot only a portion of the wave file s full amplitude range is displayed These two commands move the displayed range up or down to allow you to view the information above or below the range currently displayed Page 42 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands Amplitude View Menu gt Amplitude Amplitude Scale Log dB E jad The Amplitude Scale commands below are used to set the type of scaling used on the amplitude y axis of the main Intelligibility module plot Amplitude scaling for the impulse response plot can also be selected using the Amplitude Scale spinner to the right of the plot in the main program window Linear Scale Keyboard Command Ctrl N Displays the A D amplitude values on a linear scale Decibel Scale Keyboard Command Ctrl D Converts linear A D amplitude values to decibel values Show Schroeder Trace View Menu gt Show gt Schroeder Trace Schroeder a Keyboard Command S In addition to plotting the raw time domain data of the impulse response the Intelligi bility module can display a second trace on the plot that is the result of a Schroeder Reverse Time Integration calculation performed using the impulse response data The Schroeder trace can be useful for identifying trends in the impulse response particu larl
73. applicable as they are made The top half of the dialog box is the ntelligibility Graph where quantitative intelligibility values are plotted on three horizontal scales ranging from Bad to Excellent left to right Separate scales are provided for ALCons Clarity and STI Note that the results of two different forms of the ALCons long and short calcula tions and two types of STI results may be plotted on these two scales Also note that ALCons will appear only after setting the Ld Lr and Ln markers in the 1 octave passband centered on 2 kHz ant that STI and RSTI values are calculated only when you click the Calculate STI and RSTI button Once calculated STI and RSTI values will not change for a given file The lower section of the Intelligibility dialog box has controls for some of the parameters that affect the intelligibility calculations and display fields for additional quantitative acoustical values With the exception of STI and RSTI if calculated the acoustical values shown in this area apply only to the Band passband currently selected for display RT60 Also called reverberation time RT60 is the amount of time it would take the system to decay 60 dB at the given rate of decay RT60 Page 36 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands Early Decay Time The Early Decay Time EDT is rate at which the system under test completes e
74. arliest stage of its decay again expressed as the amount of time in seconds that would be required for the signal to decay 60 decibels at the given rate of decay Direct to Reverb The direct to reverberant level DTR This is the relative difference between the level of direct sound to reverberant energy at the top of the reverberant decay slope Calculate STI and RSTI Clicking this button will cause the Intelligibility module to calculate STI and RSTI from the impulse response data These calculations can take some time to process particularly on long files but this only needs to be done once for any file The STI and RSTI calculations are not dependent on either the positions of the level Ld Lr and Ln markers or the passband currently selected for display Clarity The Clarity field sets the number of milliseconds used for the Clarity Factor scale in the upper portion of the window For example entering 35 in this field will set the clarity scale to C35 STI and RSTI When the STI and RSTI values are calculated for the current file the results of the calculations are displayed in these two fields and on the STI scale in the upper portion of the dialog box Again the STI and RSTI values are not dependent on either the positions of the level Ld Lr and Ln markers or the passband currently selected for display Band The Band selector serves the same function as the Band spinner to the right of the plot in the ma
75. asurement make sure the Use Loopback for Time Alignment check box is checked Set the Measure ment Channel selector to match the computer line input used for your measurement microphone preamp Notice that when the Use Loopback for Time Alignment option is checked the Reference Channel is automatically set to the opposite channel When the Averages value is set to a number greater than 1 multiple MLS data sequences are recorded and the results are averaged together to produce the finished measurement Each doubling of the number of averages will yield 3 dB more signal to noise in the finished measurement however the time required to make each measure ment is increased As a general rule you will want to use higher numbers of averages in noisier environments and or when you are restricted to using lower sound pressure levels to stimulate the room system under test The sampling rate SR determines the frequency content of the completed measure ment To measure the full audio spectrum a sampling rate of 44 1 k or greater is required Using lower sampling rates will restrict the highest frequency obtainable to one half of the sampling rate the Nyquist frequency The MLS Length together with the sampling rate determines the Time Constant of the sequence also called the time window The Time Constant for the selected MLS Length and SR values is automatically displayed below the MLS Length field To obtain a solid impulse response measu
76. ata and can be useful for getting a quick overview of a signal Pink and White Noise Pink and white noise are sounds or audio signals containing random or pseudoran dom broadband energy Both are commonly used as signal sources in audio testing The difference between pink and white noise is obvious if you look at both using an RTA Pink noise appears flat on an octave or 1 3 octave band display because it has equal energy per octave 20 20 Octave Scale Octave Scale 30 40 Decibels Decibels 32 63 125 250 500 1K 2K 32 63 125 250 50 1K 2K 4K 8K 16K Frequency Hertz Frequency Hertz Pink noise on an octave band display White noise on an octave band display White noise will appear to be sloping upward to the right on the same display increasing in magnitude at higher frequencies White noise has equal energy per frequency so each higher octave has 3 dB more energy than the octave below it In fact white noise has so much high frequency energy it can damage loudspeakers if used improperly We recommend exercising great care when using it as a test signal for most electroacoustic measurement applications When making an MLS measurement keep in mind that the MLS stimulus signal is essentially white noise Page 112 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 4 Reference Schroeder Reverse Time Integration Sometimes called Schroeder Inverse Integration this is a technique for finding the
77. aved to an ASCII text file suitable for import into a spreadsheet or other applications by clicking the Save button at the bottom of the window Intelligibility Scales The top half of the Intelligibility dialog box is devoted to the ntelligibility Graph In this section objective intelligibility values are plotted on three horizontal scales ranging from Bad to Excellent left to right Separate scales are provided for three types of intelligibility values e Percentage Articulation Loss of Consonants ALCons e Clarity early to late energy ratio atn milliseconds Cn e Speech Transmission Index STI and Rapid Speech Transmission Index RSTI SIA Smaart Acoustic Tools Version 4 User Guide Page 13 Chapter 2 Intelligibility Module Functions and Commands Values for the current measurement are indicated by yellow flags plotted on these three scales Two of the scales have two sub types so there are separate flags for each The results for both the long and short forms of the ALCons calculations are plotted on the ALCons scale with the type indicated on the individual flags by the letters L for long form and S for short form Note that ALCons will appear only after setting the Ld Lr and Ln markers in the 1 octave passband centered on 2 kHz Two different values will appear on the S7 scale after running the STI calculation routine STI and Rapid STI RSTI The latter is indicated by a flag with
78. c Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands Analysis Module Functions The Time Display Time Disp CTA A o EE Co ala TY Peeve ee ena The Time Display is a detailed 0 4393 sec 60 48 dB pera view of the wave file s time En vs amplitude characteristics 2S la The Time Display is the only aa display mode available prior E to transforming a wave file o for the first time using the E Mia 11212 veau Transform command j 0 500 Time sec The default time x axis scale shows the entire waveform You can zoom to a specific portion of the waveform using the arrow keys the Time Zoom commands in the View menu or by clicking and dragging horizontally the with the mouse in the Waveform Display The Locator Bars in the Waveform Display indicate the limits of the time range currently being displayed on the main plot Amplitude Scale Log dB E v The vertical y axis range of the plot can be changed using the Amplitude gt Zoom and Move commands in the View menu or specified on the Time Display tab of the Options dialog box The amplitude scaling options for the Time Display plot are Log dB Logarithmic amplitude scaling takes the linear A D amplitude data and calculates a decibel value relative to 32767 for each amplitude unit except 0 Lin Linear amplitude scaling represents amplitude linearly as a percentage of the fu
79. ce your mouse cursor at the point on the plot where you wish to begin the decay rate calculation Hold down the left mouse button and drag the cursor to draw rubber band a line to the desired end point 0 5800 sec 24 00 dB Slope 41 38 dB sec T60 1 4 sec The line you draw remains visible on the plot when you release the mouse button The relative time and amplitude difference between the end points of the line the decay slope in dB per second and equivalent RT60 value will be displayed in the relative cursor readout above the Waveform display to the right of the tracking cursor readout To clear the line click once on the plot with your left mouse button FFT Frame Selection in Frequency Slice Mode 38 6 38 6 54 4 e 54 4 0 000 0 250 0 000 0 250 In Frequency Slice mode two vertical striped Frame Locator bars in the Waveform display indicate the time position of the FFT Frame currently displayed in the plot area To select a different FFT frame for display using your mouse place the mouse cursor over any point in the Waveform Display and click the left button once The Frame Locator Bars will move to the new location and the data from the selected FFT frame will be displayed on the main Frequency Slice plot Page 102 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands Frequency Masking Frequency Masking is useful when analyzing signals known
80. common waterfall display Spectrum The frequency content of a given signal Speed of Sound The speed of sound is dependent on the material of propagation the temperature and several other factors Typical values for the speed of sound in air are 1120 ft sec or 341 376 m sec This is the default value SIA Smaart program modules use to calculate distance equivalents for time differences White Noise A random or pseudorandom signal in which over a given averaging period each frequency has equal energy SIA Smaart Acoustic Tools Version 4 User Guide Page 117 Selected Bibliography The following is a list of publications suggested for readers who want to expand their understanding of the physical and theoretical concepts and mathematical procedures underlying SIA Smaart software products sound system design and the study and practice of acoustics Ballou G Ed Handbook for Sound Engineers The New Audio Cyclopedia Indianapo lis Howard W Sams Co 1987 Bensen K B ed Audio Engineering Handbook New York McGraw Hill Book Co 1988 Out of Print Beranek L L Acoustical Measurements New York John Wiley and Sons Inc 1949 reissued by the American Institute of Physics for the Acoustical Society of America New York 1986 Beranek L L Acoustics New York McGraw Hill book Co 1954 reissued by the American Institute of Physics for the Acoustical Society of America New York 1986 Brigham E The Fast
81. cord button The counter begins running and the Record button changes to a Done button The length of the recording is limited only by the amount of disk space available When you are finished recording click the Done button to close the dialog box and immediately load the new wave file into the Analysis module To exit the dialog box without loading the recorded file click Cancel SIA Smaart Acoustic Tools Version 4 User Guide Page 75 Chapter 3 Analysis Module Functions and Commands Play Audio Menu gt Play Keyboard Command Shift P The Play command begins audio playback of a wave file open in the Analysis module If two files are loaded the one displayed on top is played If you are zoomed in on the time axis only the displayed portion of the file is played During play a progress indicator shows the approximate time position of the data being played Pause Audio Menu gt Pause Select this command to pause the audio playback Repeat the command toggle off to resume the playback at the point at which it was paused Stop Audio Menu gt Stop Stops audio playback Page 76 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands View Menu Commands Mode The Mode commands switch the Analysis module between its four primary display modes Time Display View Menu gt Time Display Time Disp P Keyboard Command D The Time Display plots a detailed vie
82. display or by clicking the Frame Range readout and entering a range of FFT frames in the pop up dialog box Two options are available on the Spectrograph tab of the Options dialog box that alter the way the individual sections of the vertical bars are plotted The option used in the illustration above is the default Uniform setting This option displays the Spectrograph as a continuous color map Selecting Relative varies the horizontal width for each section relative to its magnitude value higher magnitudes are wider Comparing Two Wave Files The Analysis module allows you to open two files at the same time and compare their time and frequency domain data in Time Display Time Slice and Frequency Slice display modes This feature is useful for assessing the effectiveness of acoustical treatment in a room or any other application that requires comparing two signals The Analysis module can also create a new wave file that represents the difference between the two files o MEEA E OE To load a second file into the Analysis module first open File 1 as you normally would the click the File 2 button above and to the left of the plot This button calls a Win dows Open file dialog box prompting you to select a wave file The second wave file must be recorded at the same sampling rate and resolution 8 24 bits sample as File 1 and must be of the same type stereo or mono but does not have to be exactly the same size SIA Smaart Acou
83. dpass filters are stored in ASCII text format to allow advanced users to make change the stock filters or write their own SIA Smaart Acoustic Tools Version 4 User Guide Page 25 Chapter 2 Intelligibility Module Functions and Commands Band Broadband EE j i The ASCII filter files are kept in the Filters sub directory folder in the main program folder The Intelligibility module creates its lists of available filters each time you start the program based on the information in another text file called filterfiles txt also located in the Filters folder This file contains a list of the individual filter file names and other information about each file such as the sampling rate filter type and list name In addition to the 1 1 and 1 3 octave filters types there is also a provision for a third User filter type User filters if present are made available from the Band spinner whether the 1 octave or 1 3 octave filters sets are selected The Intelligibility module accepts either FIR or IIR time domain filters For more information on custom izing the filter lists please refer to the instructions included in filterfiles txt Setting up Links to Other Programs AcousticTools In addition to the built in links between the Intelligibility and Analysis modules see Analysis on page 30 and ntelligibility on page 70 both SIA Smaart Acoustic Tools program modules can be configured to start and pass Wave wav or A
84. e Range Selection 101 Analysis Module Commands 68 Audio Menu Analysis Module 75 76 File Menu Analysis Module 68 ASCII Save 71 Close File 1 68 Close File 2 69 Configuration 73 Exit 74 File Info 69 Intelligibility 70 Open File 1 68 Open File 2 68 Print 73 Print Preview 74 Print Setup 74 Save Difference As 70 Save Wave Zoom As 70 71 Transform 71 Options Menu Analysis Module All 89 Calibrate 89 Color 89 Devices 91 Frequency Zooms 91 Meters 92 Power Spectrum 93 94 Printing 93 Rainbow 94 Set All Options to Default 99 Slice 95 Time Display 98 99 Waveform 99 View Menu Analysis Module 77 Amplitude 79 Change Z Order 87 Channel 78 Cursor 85 86 87 88 89 Default Zoom 87 File 2 84 85 86 87 88 89 Frequency 82 83 84 Mask 83 84 Mode 77 Normalized 88 Rainbow 87 88 Show 89 Slice 81 Time Zoom 78 Analysis Module Functions 59 Frequency Slice 62 Power Spectrum 63 Power Spectrum 64 Time Display 59 Time Slice 60 Analysis Module Functions and Commands 54 Appearance 92 ASCII Save 71 Attenuation 115 Averages 32 34 Page 126 SIA Smaart Acoustic Tools Version 4 User Guide Band 13 25 46 Bar Width 96 Basic Theory Data Window Functions 107 Frequency Resolution 109 Linear amp Logarithmic Scales 111 Octave Band Resolution 112 Pink White Noise 112 Sampling Rate 113 Bibliography 118 bitmap 28 C C n 49 C35 49 50 C50 49 50 C7 49 50 Cables and adapters 3 Calculate STI and RSTI 37
85. e eine 29 vn VAT O tierce yee Terre eee er 30 Record Impulse A AAA ean eae ed 31 Create Impulse From File nirien arida iin 34 Intelligibility Graph oonnninnnni nnn nacion noni 36 All Bands Table ici aaa A 38 SetAllVal es to Default aia A a E troba 39 O aa 39 O oi aaaS 40 POE UA aia 40 View Menu Commands c cccccssscsesssesssssessssssssesecsssecsesaesesaesessesessesecsesacsesaueesausessesessesanersaneess 41 a o ta ale dad ode 41 AMP cast tt ene nas 43 SHOW A E a dai Manns 43 Mare a dale 45 Track Nearest Data Points 60 io iia 46 Octave Band Filters and 1 3 Octave Band Filters csccecssssssssssssssesssseesssesrsassesesesereeees 46 Cae 46 Options Menu Commands cececccecceseseeeeeeeeceeeeseeeeecaeseeeecaeaeeeeecaeaeeeeecasaeaeeesesaseeesesasaeaeees 47 A A NA 47 LG 0 pene ee T AI EE AA E EN IE E PIA eS O a ed 47 DEVICES mininin a aaa aa ids 48 Graph Sentira O 49 M ter Anrini Adin Wanna aan EE EE A AAAA nai awareness 50 Printing cr innan add devices 52 Intelligibility Module Keyboard Shortcuts ooocicicicicicncncnononononononononororo nono nono nono rr nono rr rro 53 Section 3 Analysis Module Functions and Commands oocciccconicinoccnnanono 54 Navigating in the Analysis Module cccccscsssssssssssssesssssessssssessesessesesseseeeesasesansessesasensasers 54 AAA A Ae eA aes SATA 55 Fille Intormati0ON 0d dd 55 EETINTOMAtI N etecceA essere ts Ate tr Avte In a Aci IE Ags 55 F
86. e end points of the line rather than the Lr and Ln markers Clicking once on the plot while holding down the Shift key will erase the line A Shortcut for Positioning the Ld Lr and Ln Markers Notice that if you press the Alt key while the mouse cursor is positioned over the plot the cursor mouse changes to a marker symbol with a plus sign in the center Clicking the left mouse button while holding down the Alt key moves the selected level marker to the mouse cursor location You can select the Ld Lr or Ln markers using the Tab key or by simply clicking a marker with your mouse You can also move the markers around on the plot using the arrow keys or by clicking on a marker and dragging it moving the mouse while holding down the left mouse button from one place to another For more information on setting the Ld Lr or Ln markers refer to Calculating Intelligibility from an Impulse Response on page 10 Page 24 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands Zooming With the Mouse Your computer s mouse or other pointing device can be used to set both the time x MA axis and amplitude y axis ranges on the main Intelligibility module plot Notice that if you press the Ctrl key on your keyboard while the mouse cursor is positioned over the main plot the mouse cursor changes to a magnifying glass with a plus sign in the center If you click on the plot while the
87. e more rigorous STI calculation which takes into account almost the entire audible spectrum Sampling Rate The sampling rate in digital audio is the number of times per second an analog audio signal is sampled and digitized The most important practical consideration is that the sampling rate limits the frequency content of the signal being digitized A general rule is that sampling rate should be at least double the number of Hertz in the highest frequency you want to include in the digitized signal The frequency that is equal to one half of the sampling rate is called the Nyquist frequency Some other issues affect the highest frequency you can accurately measure in sampled signals In theory you can measure to half the sampling frequency but SIA Smaart Acoustic Tools Version 4 User Guide Page 113 Chapter 4 Reference in practice things like aliasing Sigma Delta conversion and anti aliasing filters make frequencies close to the Nyquist tricky to measure Compact discs run at a standard sampling rate of 44 1 kHz Professional digital audio recording machines often sample at 48 kHz Computer sound cards generally run at one of several user selectable sampling rates such as 44 1 kHz 22 05 kHz or 11 025 kHz The SIA Smaart Intelligibility module determines the available sampling rates by polling your computer s sound card each time it loads Currently the fastest sampling rate supported by any SIA Smaart program module is 48 kHz Ge
88. e same basic principle They de weight the samples nearest to the beginning and end of the FFT data series to help reduce these truncation errors or edge effects The only real difference between different the Data Window types is the shape of the window The Analysis module provides several different Data Window options including Hanning Hamming Blackman Blackman Harris Parzen and Welch The option labeled None for no data window also called a rectangular window should be avoided for most applications Decibels The decibel dB is a unit used to express the logarithmic ratio of two amounts of power voltage or any two values Typically decibels are used when the two values may differ over a very large range The need for logarithmic scales in acoustics and audio is a result of the wide range of sensitivity to sound intensities frequencies and pressures that makes up the range of human hearing For example a decay of 60 dB represents a sound that has decayed by one million times in terms of energy Most measurements in audio are based on either voltage or sound pressure and are expressed in decibels The key point to understanding the decibel is that it is used to describe a comparison of two values Two useful points regarding decibels to remember e Decibels are always a ratio of one value to another You must know the reference value in order to calculate the decibel values e 0dB can mean several
89. e system under test Averages Setting this value to a number greater than 1 causes the Intelligibility module to record and average the results of multiple MLS stimulus sequences to produce the finished measurement Each doubling of the number of averages will yield 3 dB more signal to noise in the finished measurement the lower limit being the noise floor of the measurement system or the system under test whichever is higher however the time required to make the measurement is increased SR Sets the sampling rate to be used to record the impulse response measure ment Again the highest frequency obtainable at a given sampling rate will be equal to one half of the sampling rate the Nyquist frequency MLS Length Like the FFT size parameter on the Dual FFT tab this value specifies the size in samples of the MLS stimulus sequence Together with the sampling rate the MLS Length determines the size of the Time Constant or time window for the measurement as well as the size of the resulting wave file Time Constant The time window for the impulse response measurement This value is not directly editable but is a function of the selected FFT size and Sampling Rate MLS Length divided by Sampling Rate Time Constant As with Dual FFT measurements this value should always large compared to the total decay time of the room system under test Create Impulse From File File Menu gt Create Impulse From File Keyboard Com
90. e two signals are then compared in the frequency domain using a transfer function calculation and the results are converted back to the time domain for display and analysis Since both the reference and measurement signals travel through the same processes analog I O stages A D and D A leaving entering the measurement system the Dual FFT technique can be more forgiving of less than perfect computer sound hardware This technique can also be used with half duplex sound hardware capable only of playing or recording at any one time provided an external test signal source is used The relative disadvantage of the Dual FFT method is that it is typically necessary to average the measurement over a longer period of time to approach the kind of signal to noise ratios possible with MLS This method also requires much more processing power than MLS less of an issue now than in the past and is theoretically less repeatable since the test signal is a more random quantity In practice you can obtain very solid repeatable measurement results using either recording method and it is even possible to combine the two by using an MLS stimulus with the dual FFT method Recording an Impulse Response Using MLS The Maximum Length Sequence MLS technique for measuring the impulse response of a system is stimulus dependent requiring the use of an MLS stimulus signal An MLS signal is pseudo random generated using a system of bit shift registers and a
91. eater than 1 is selected the specified number of frames are recorded and then averaged together to calculate the impulse response With every doubling of the number of the number of frames averaged the signal to noise S N ratio of the measurement will increase by 3 dB the lower limit being the noise floor of the measurement system or the system under test whichever is higher The trade off is that it takes longer to record and process the data for the measurement SR Sets the sampling rate to be used to record the impulse response This value determines the frequency content of the measurement The highest frequency obtainable at a given sampling rate the Nyquist frequency will be equal to one half of the sampling rate As a general rule you will probably want to use a sampling rate of 44100 or greater to obtain a full bandwidth impulse response A lower rate might be preferable when measuring a subwoofer system a band limited system or a room system with a decay time significantly longer than five to six seconds FFT size This value specifies the size in samples of the Fast Fourier Transform FFT used in the impulse response calculations Together with the Sampling Rate the FFT size determines the length of the FFT Time Constant or time window for the measurement as well as the size of the resulting wave file FFT Time Constant The time window or length of time covered by an individual FFT Frame This value is n
92. eesetaes 70 Save Difference AS ceccccscssescsesenseeeeeeneeesecseseeeeeseeececaesesesecaesseeeesaeaseeeesesasieeesetasseeenesasiaas 70 ASCII Mei 71 Tran STON oenn di 71 alele TILEN AEAEE sitet E EEE EE E E EEE EEATT 73 AASTA AAAA AA AAE TA EA A AAA TOOT 73 PHNGRIEVIEW Aeneid Ah oh thei Aha deidad 74 Print Setup asias 74 Ebola a tdi dial aw a a 14 Audio Menu COMMANdS oocicciccionnnnnnnonnnncnccncn concierne 15 A AA 15 Play CEOPOAOLA OOOO o casuceshubesceshsecaducusesh caveveshcovacececvcseels 76 A 76 NICO AAPA ATEREA TEA TATATATA ATAATA TATATATA ATAATA TATTA AT ETUAAN 76 A O ATT 77 Ene EEAS A TTA TATA TATATATA TATA AATA TA TAATOA TAE TAS 78 eO a a aE 78 AA a a eee eae hae 79 SiC EE EE EE E E E 81 FOQUGNCY EAE 82 Mask ocn A ESKAE AAA REE RE 83 lO nana ii iii idad ee 84 A iis delet esdeen die hte des iaee chee dhesstis hcnihan chet xebca adai aia aiaia etene aiaiai 85 Change Z Order icon pirita 87 Det auilt ZOOM o iaa 87 A O E 87 Normalized cai nar iaa 88 Power SPECT sinsero erdele cided adele dideldadele diel adele diet arietndyiaelt 88 Options Menu Commands ccececcsesceseseeseeseeceeeeseeesecaeseeeeecaeseeeeecaeaeaeeesaessaeeesesaeieeesetasaeeees 89 NN 89 Calibrate ui A AAA 89 Col ios cai annie aed 90 DeVICGS acia 91 Frequency ZOOIMS corri tii dia 91 Meter a 92 Power Spectrum cococococococococococonocononononononononono nono nono nono no DR RR RD DR RD RN RR RN RD DD no nr anno nrnrnnnrnrnrnrnrnrnrnrnrnenoss 93 IH
93. en a line is drawn on the plot with the pencil tool this field displays the S ope of the line in dB second and the Page 8 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands equivalent RT60 value In dB amplitude scaling mode when the normal impulse response plot displayed and no line is present the readout area displays slope and RT60 values based on the locations of the Lr and Ln markers Plot Area The largest portion of the Intelligibility module s main window is devoted to the display area for impulse response and ETC data plots The plot area will appear blank until a wave wav file is loaded or recorded When a file is loaded a time domain time vs energy representation of the wave file data appears in the plot area Jump To Other Programs Analysis Clicking the button in any display mode will automatically close the Intelligibility module while opening the Intelligibility module and loading the file that was open in the Intelligibility module AcousticTools Clicking the Acoustic Tools logo above the Analysis button will pop up a menu that allows you to jump to and pass data to other programs if there are jumps defined it imjumps txt See Setting up Links to Other Programs on page 26 for more information Display Controls The controls to the right of the plot area in the main program window affect the appearance of the main impulse ETC plot and open the In
94. en the time axis scale is changed the boundaries of the currently displayed time range are indicated by range locator bars in the Waveform display Frame Range In Time Display mode the precise sample range displayed in the Sample Range readout to the right of the plot In Time Slice and Spectrograph modes the Sample Range readout is replaced by a Frame Range readout that shows the FFT frame range currently displayed Clicking either of these readouts with your mouse will pop up a dialog box allowing you to specify a time range in samples or FFT frame numbers depending on the display mode Mouse Shortcut The time range for the Time Display Time Slice and Spectrograph display modes can also be set by clicking and dragging horizontally with the mouse on the Waveform display See page 100 for more information Amplitude Zoom In Out View Menu gt Amplitude gt Zoom In Out Keyboard Commands Zoom Out Zoom In These two commands increase or decrease the vertical y axis magnification of the Time Display Time Slice and Frequency Slice plots by decreasing the displayed amplitude magnitude range SIA Smaart Acoustic Tools Version 4 User Guide Page 79 Chapter 3 Analysis Module Functions and Commands Move Up Down View Menu gt Amplitude gt Move Up Down Keyboard Commands Move Up Page Up Move Down Page Down When you are zoomed in on the vertical y axis range of the main plot only
95. erberant spaces the amplitude of the peak is a function of the signal to noise ratio of the measurement signal Another way to increase the signal to noise ratio of both MLS or Dual FFT measure ments is to increase the number of averages by increasing the Averages value in the Record Impulse dialog box If this value is greater than 1 the Intelligibility module records the specified number of FFT or MLS frames and averages the data from all recorded frames in the impulse response calculation Each doubling of the number of frames averaged will yield 3 dB more signal to noise down to the absolute noise floor of the system under test or the measurement system whichever is higher Insufficient Time Window If the impulse measurement plot appears erratic without a single strong peak and or with several peaks of nearly equal amplitude the reason could be that the FFT or MLS Time Constant is too short Check to insure that the time constant is set to a value larger than the decay time of the system under test and increase the FFT size MLS Length or decrease the sampling rate if necessary SIA Smaart Acoustic Tools Version 4 User Guide Page 123 Appendix A Troubleshooting Negative Delays Dual FFT Only An oddity of the Dual FFT impulse recorder mathematics causes negative delays to be wrapped around and displayed at the end of the time scale When this happens the strongest peak in the impulse response will show up cl
96. eseeeeeeeeeeseeeeecesaeseeesetaseeetesanaeeees 122 Input Levelsiss 4 A E etiotighatedalinialis deol eatiindon 122 Problems With the Intelligibility Module Impulse Response Recorder ccceceeeeeeees 123 Printing Problems E EI terete ess 124 Restoring the Default Configurations ccceccccseseeseceseteeeeeceeeeeeeceeseeeeseeaseeesetasieeetetanieeeees 125 On line Help and Readme Files cccecsccseseeseeceeeeeeeceeseeeeeceeseeeeeceeaeseeecesaeaeeesesasaeeesetaeaees 125 Technical SUPDO siria dada cdi 125 A ae eerie ier Fc eae seca eave T TS 126 vil Chapter 1 Getting Started System Hardware Recommended Configuration Minimum Configuration e Microsoft Windows 95 98 or e Microsoft Windows 95 98 or NT 4 0 or higher NT 4 0 or higher e 166 MHz or faster Intel Pentium e 90 MHz or faster Intel Pentium or compatible microprocessor or compatible microprocessor e 32 64 Mb system RAM e 16 24 Mb system RAM e 800 x 600 x 256 color Super VGA e 800 x 600 x 256 color Super VGA display display e Windows compatible sound e Windows compatible sound hardware with stereo line level hardware with stereo line level input s 16 24 bit resolution input s 16 bit resolution 44 1 k selectable sampling rates from and or 48 k sampling rate capable of 5512 to 48 k capable of full half or full duplex operation duplex operation When installed the program and support files require approximately 12 Mb of
97. everberation Time 117 RSTI 13 RT60 13 36 117 S Sampling Rate 113 117 sampling rate 19 22 32 34 Save As 29 Save Difference As 70 71 Save Filter Data in Memory 50 Save Wave Zoom As 70 71 Scale 25 41 42 43 46 49 Schroeder On Top 44 46 Schroeder Reverse Time Integration 113 Schroeder Trace 43 44 46 Screen Capture 28 Screen shots 28 Select Change First FFT Center to Peak 101 Select Change Normalization Point 101 Selected Bibliography 118 Selecting Sound Hardware 48 Set All Options to Default 99 Set All Values to Default 39 99 125 Set FFT Center to Peak 85 86 Setting Measurement Parameters Dual FFT 21 MLS 18 Setting FFT Center Point Using Your Mouse 86 Shift Up Down 85 86 Shortcuts Keyboard 53 104 Show 89 ETC 44 Schroeder On Top 44 Schroeder Trace 43 Slice 81 95 Sound Hardware About 1 Spectrogram 117 Spectrograph 64 Spectrum 117 Speech Transmission Index STI RSTI 113 Speed of Sound 49 98 117 SR 32 34 STI 13 37 System Hardware 1 Minimum Configuration 1 Recommended Configuration 1 Page 130 SIA Smaart Acoustic Tools Version 4 User Guide T Technical Support 125 Time Constant 32 34 Time Display 59 Options 98 99 Time Range 49 Time Range Selection 101 Time Slice 60 95 Time Zoom 78 Track Nearest Data Point 46 Transfer Function 114 Transform 71 Troubleshooting 120 Input Levels 122 Installation Issues 120 Printing Problems 124 Sound Cards 121 Technical Support 125
98. evices View Menu gt Devices If your computer has more than one sound card or driver set installed the Devices tab of the Options dialog box allows you to select which devices the Analysis module should use e Wave In Selects the device to be used for audio recording e Wave Out Selects the device to be used for audio output wave file playback Frequency Zooms View Menu gt Frequency Zooms Keyboard Command Z This section of the Options dialog box controls frequency ranges for the four Frequency Zooms e MIN Sets the lowest frequency displayed when the zoom preset is selected e MAX Sets the highest frequency to display Entering the word Nyquist in this field automatically sets the MAX frequency to the highest frequency obtainable at the wave file s sampling rate Nyquist Frequency Hz Sampling Rate 2 SIA Smaart Acoustic Tools Version 4 User Guide Page 91 Chapter 3 Analysis Module Functions and Commands Meters Options Menu gt Meters The settings in the Meters tab of the Options dialog box control the appearance and behavior of the Input Level Meters in the Record Wave File dialog box The meters are calibrated to regard the maximum digital output of the A D system of the sound card being used normally 16 24 bits as 0 dB Peak Hold e Peak Hold When this box is checked the input level meters will continue to indicate the highest input level encountered in the input signa
99. g off the plot anywhere in the margins of the plot area To clear the FFT center point selection press Ctrl X Note that specifying the first FFT center point only works if are enough samples between the beginning of the file and the selected FFT center point for the first half of the FFT If the selected center point would cause the first FFT to overrun the beginning of the wave file the program will default back to beginning the first FFT on the first sample in the wave file when the file is transformed Select Change Normalization Point for Rainbow Display The Time Slice mode Rainbow display plot can be normalized so that the three Time Slice traces have the same amplitude at a point you select When Normalize is on two vertical white lines appear on the plot to indicate the normalization point To move the normalization point hold down the Shift key while clicking on the plot typically near a peak on one of the traces with the left mouse button Pressing the N key toggles normalization on and off SIA Smaart Acoustic Tools Version 4 User Guide Page 101 Chapter 3 Analysis Module Functions and Commands Delta Decay Rate Calculation In Time Slice mode you can use your mouse to calculate the decay rate for an impulse response recorded in a wave file The same procedure can be used to find the time and ampli tude difference between two points in the Time Display mode To perform this procedure pla
100. g on and off The mask is kept in memory until you clear it see below or exit the Analysis module SIA Smaart Acoustic Tools Version 4 User Guide Page 83 Chapter 3 Analysis Module Functions and Commands Clear Mask View Menu gt Mask gt Clear Mask Keyboard Command Ctrl Shift M Clears all masking information from memory allowing you to create an entirely new mask rather than adding to an existing mask File 2 The File 2 commands control the relative time offset for File 2 when two wave files are open in the Analysis module The Move time offset commands above are enabled in Time Display mode only Note that File 2 time offset may also be specified in samples in the File Information dialog box Move Left View Menu gt File 2 gt Move Left Keyboard Command Ctrl Left Arrow Fine negative time offset adjustment moves the File 2 trace one pixel to the left Move Right View Menu gt File 2 gt Move Right Keyboard Command Ctrl Right Arrow Fine positive time offset adjustment moves the File 2 trace one pixel to the right Move Left Fast View Menu gt File 2 gt Move Left Fast Keyboard Command Ctrl Shift Left Arrow Coarse negative time offset adjustment for the File 2 trace Move Right Fast View Menu gt File 2 gt Move Right Fast Keyboard Command Ctrl Shift Right Arrow Coarse positive time offset adjustment for the File 2 trace Reset to No Shift
101. g tab of the Options dialog box controls the appearance and content of pages printed directly from the Intelligibility module The following options are user definable Title 1 2 and 3 You can specify up to three lines of title text to appear at the top Intelligibility module printouts If any of the three Title fields is left blank that line is omitted on the printed page Print Type The two radio buttons in this section determine what type of information will be printed When the Impulse and Intelligibility Graphs option is selected the printed page will include both the impulse response plot and the Intelligibility Graph If the A Bands Table option is selected only the All Bands Table is included on the printout Print File Name When this box is checked the name of the wave file currently loaded in the Intelligibility module on which the printed information is based will be included in the title area at the top of the printed page Print Today s Date lf this box is checked the current date as set on your computer will be inserted in the title area at the top of the printout If you want to use a date other the current system date of your computer on the printout un check this box and type the desired date as one of the Title lines Show custom print dialog before print and print preview When this box is checked selecting either the Print or Print Preview commands will open the Custom Print Information dia
102. hard disk space Keep in mind that working with audio waveform wav files can use up a lot of real disk space It s not unusual for a single waveform file to require 500 kb or more and due to the nature of the data they don t compress very well if you use disk compression software The same is true of frequency domain data files created by the SIA Smaart Acoustic Tools Analysis Module About Sound Hardware SIA Smaart Acoustic Tools is designed to work with any Windows compatible sound device Only the A D and D A portion of the computer s sound hardware are actually used so the software will work well with a wide variety of devices including off the shelf sound cards for desktop machines and the built in sound sections of most notebook computers SIA Smaart Acoustic Tools Version 4 User Guide Page 1 Chapter 1 Getting Started Two independent external line level input channels typically in the form of a single stereo connector are an absolute requirement for recording impulse response measurements using the Dual FFT method and or for time locked MLS recording We do not recommend using the microphone level inputs on most computer sound cards for any type of measurement For microphone measurements an external mixer or microphone preamp should be used with the computer s line level inputs Addition ally the sound hardware must be capable of full duplex operation if you intend to use the Intelligibility module s i
103. he All Bands Table For example if this value is set to 50 milliseconds the default setting the Intelligibility module will use C50 as the Clarity Factor in intelligibility displays Changing this number to 7 or 35 will change the Clarity Factor to C7 or C35 respectively Meter Options Menu gt Meter The settings on the Meters tab of the Options dialog box control the appearance and behavior of the nput Level Meters in the Record Impulse dialog box The meters are calibrated to regard the maximum digital output of the A D system of the sound card being used normally 16 24 bits as 0 dB with all other values given as dB down from zero The following meter options are user definable e LED Levels The Intelligibility module allows you to specify amplitude values for each individual Left Right pair of LEDs Page 50 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands Peak Hold When this box is checked the meters will continue to indicate the highest amplitude level encountered in the input signal for a specified period of time after the level drops off Hold Peak For Specifies the length of time in seconds the meters will hold peak levels when Peak Hold see above is enabled Averages Setting this value to a number higher than one will cause the meters to display a running average of the specified number of samples rather than simply reacting a
104. he displayed time range of the main plot Note that you can also zoom in on both the x and y axes of the plot and zoom out using your mouse For more information on this feature please refer to the topic titled Zooming With the Mouse in the Shortcuts section SIA Smaart Acoustic Tools Version 4 User Guide Page 41 Chapter 2 Intelligibility Module Functions and Commands Move Range Left Right View Menu gt Zoom gt Move Range Left Right Keyboard Commands Move Range Left Ctrl Left Arrow Move Range Right Ctrl Right Arrow When you are zoomed in on the horizontal x axis range of the main plot only a portion of the wave file s full time range is displayed These two commands move the displayed range left or right to allow you to view the information before or after the range currently displayed Zoom Y In Out View Menu gt Zoom gt Zoom Y In Out Keyboard Commands Zoom Y In Zoom Y Out These two commands increase or decrease the vertical y axis magnification by decreasing the displayed amplitude range of the main plot Note that you can also zoom in on both the x and y axes of the plot and zoom out using your mouse For more information on this feature please refer to the topic titled Zooming In and Out on the Plot With the Mouse in the Shortcuts section Move Range Up Down View Menu gt Zoom gt Move Range Up Down Keyboard Commands Move Range Up Page Up Move R
105. he output of the system is returned to the other input as the measurement signal Microphone Preamp Phantom Loudspeaker Power Suppl Py E System Under Test Signal Amplifier Source Reference Signal Dual FFT measurement setup using an external signal source The diagram above shows a typical measurement system setup for Dual FFT mea surement using the internal signal generator as the reference signal source The diagram below shows a Dual FFT measurement setup using an external signal source ree To begin the recording process open the Intelligibility module and click the Record Rec button When the Record Impulse dialog box appears click the Dual FFT tab at the top of the dialog box to display the Dual FFT recording controls Dual FFT Setting Measurement Parameters If you intend to use the internal signal generator to make your measurement set the Level control in the Pink Noise Generator section to a low number initially In the Impulse Output File field you can type the path and file name for the wave file to be used to store the measurement results or click the Browse button and use the Open file dialog box to navigate to the desired folder and specify a file name When the Averages value is set to a number greater than 1 the specified number of FFT frames are recorded and processed and the results averaged together to produce the finished measurement Each doubling of the number of averages will yield
106. he specified File Name plus a single letter indicating the filter type o for octave t for 1 3 octave or u for user and the filter name in parentheses For example if you entered room wav in the File Name field and chose to save the broadband data plus filtered versions for the octaves centered on 250 Hz 500 Hz and 1 kHz using the stock 1 octave bandpass filters you would create the following files room wav the unfiltered broadband data room_o0 250 Hz wav the original data filtered for the octave centered on 250 Hz room_0 500 Hz wav the original data filtered for the octave centered on 500 Hz room_o 1kHz wav the original data filtered for the octave centered on 1 kHz Analysis File Menu gt Analysis Analysis This command opens the SIA Smaart Acoustic Tools Analysis module automatically loading the same wave file currently that is open in the Intelligibility module Since neither program normally alters the wave file in any way it is not a problem for the two programs to have the same file open at the same time The Analysis module allows you to transform the wave file data into the frequency domain using a series of Fast Fourier Transform calculations and display both time and frequency characteristics several different ways For more information about the Analysis module please refer to the Analysis module section of your S A Smaart Acoustic Tools User s Manual or the Analysis module
107. help file Page 30 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands Record Impulse File Menu gt Record Impulse Rec Keyboard Command Ctrl R This command opens the Record Impulse dialog box where you will find controls for the Intelligibility module s impulse response recorder The impulse response recorder allows you to measure the impulse response of the room system under test using either a Maximum Length Sequence MLS or stimulus independent dual Fast Fourier Transform FFT transfer function technique The Record Impulse dialog box has two pages or tabs a Dual FFT tab and an MLS tab Each tab has it s own signal generator controls and input level meters You will need to specify measurement parameters and an output file name for the impulse response data The impulse response is written to a standard Window wave wav file When you have selected your measurement parameters click the record button The intelligibility module will record and process data based on your selections write the measurement results to the specified file name and then close the dialog box and load the new file automatically The measurement parameter controls on each tab are very similar but not identical The Dual FFT Tab Dual FFT mis Recording an impulse response using the Dual Pink Noise Generator FFT method is identical to the technique used Ga
108. iffs Prentice Hall Inc 1975 Oppenheim A V Willsky A S amp Young I T Signals and Systems Englewood Cliffs Prentice Hall Inc 1983 Otnes R K Enochson L Applied Time Series Analysis New York John Wiley and Sons Inc 1978 Rabiner L R amp Rader C M ed Digital Signal Processing IEEE Press Selected Reprint Series New York IEEE Press 1972 Strutt J W Lord Rayleigh 1877 Theory of Sound New York Dover Publications 1945 Tremaine H Audio Cyclopedia Second Edition Indianapolis Howard W Sams amp Co 1969 Out of Print SIA Smaart Acoustic Tools Version 4 User Guide Page 119 Appendix A Troubleshooting Installation Issues SIA Smaart Acoustic Tools is written for use with Microsoft Windows It is a native 32 bit Windows application The installation program will not run from the DOS prompt See Section 1 Getting Started for installation instructions Versions of Microsoft Windows previous to Windows 95 NT 4 0 are not supported Windows must be running properly on your system before you can install or run this software A valid Serial Number and Install Name are required is required to install Smaart Acoustic Tools The serial number and install name are keyed to the product code on your installation and will only work when installing from a CD with the identical product code Your Serial Number and Install Name and installation CD Product Code are imprinted on the registra
109. ignal recorded after traveling through the system When two separate files are used they must also be recorded at the same sampling rate The MLS method uses only one wave file the measurement file and compares it to internally generated MLS data This technique can yield very good results however there are a couple of important caveats that you should be aware of when using it First the MLS data used to record the measurement file must be identical in length to the internally generated sequence selected for comparison and generated using an identical group of seed numbers Any two MLS stimulus signals of identical length generated at the same sampling rate using identical seed numbers should be identi cal And in practice many MLS generators do in fact use the same seed numbers however there is no accepted standard that says they must The second issue when using the MLS technique is that to obtain the best results sampling rates should be consistent throughout the signal generation output and recording processes If you want to be absolutely safe on both counts use the Intelligibility module s internal MLS signal generator accessible through the MLS tab of the Record Impulse dialog box to create your MLS stimulus signal You can connect the computer directly to the system under test or record the internally generated signal to CD or DAT through a digital output Be careful to note the sequence length and output the signal at a sam
110. iguration data for the Analysis module is stored in the Windows registry The program s registry stores the state of nearly all user definable parameters Export This command is used to extract a copy of the entire Analysis module registry from the Windows registry registration database to a reg file on disk Selecting Export opens a standard Windows file Open dialog box allowing you to specify a file name and destination folder for the new file This feature is useful for backup purposes or moving your preferences to a new computer Import The Import command opens a standard Windows Open file dialog box allowing you to import a previously saved registry reg file into the Windows registry This replaces all registry entries for the Analysis module with the information in the registry file Print File Menu gt Print Keyboard Command Ctrl P The Print command first takes you to the Custom Print Information dialog box to allow you to set title text and other options for the printout before printing The Custom Print Information dialog box can be used to set all the same printing options as the Printing tab of the Options dialog box After setting title and page options click the OK button in the Custom Print Information dialog A standard Windows Print dialog box will then open to allow you to select a printer and set up your printer options before sending the document to print Note If you un check the Show custom print
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112. ility from an Impulse Response s sssssssssssesssrsnssrnssrnssrrssrsrnnrsrnnrnrnnnsrennss 10 AARET EAE N AAE AAAA TATEA AATA AAT 12 The Intelligibility Graphs saiast ieaiaia pnia aannaaien iania at ia aaia anadai inaia ianiai 13 Recording an Impulse Response c cccccseeceeeseeeeeeeceeseeeeeceeaeseeeesaeseeeeesaeseaenesesaeeeesesaeeeetetaes 15 MES Or Ua EE od EET 15 Recording an Impulse Response Using MLS sssscssscsssescscscscsescseseneseseeeieesieeieseees 17 Recording an Impulse Response Using Dual FFT ccccececcseseeseeeeseeeeeceeseeeeesesaeeeeesetaeaees 20 Finding Time and Amplitude Differences ccccecsceseeseseeeseteeeeeeseeeeeecaeseeeeseeseeeesetaneeetetaes 24 A Shortcut for Positioning the Ld Lr and Ln Markers ccccceccssesssessssssssssssssssserssesessesesrseees 24 Zooming With the MOUSE cecccceeeseseeseeeeeeeeseeeeeeecaeseeeeecaesceeeecaeaseeeeseeaeaeeesesasieeeeetasaeeesetaeates 25 About Intelligibility Module Filters ooo nonncininnlncicin n nooo 25 Setting up Links to Other Programs cccccccccsssssscsescscscsescececececececesecenececececeseeeseseseeeeeeeeneeersees 26 Making a Screen Capture iii 28 Intelligibility Module Commands 2 c cccceecesseseesseeeeeeee cases cases saeeeseeesesaeeesaeeeeeeeeeeeees 29 ii AEEA Asean ca ovatice punta ce ceed pats lt a ctet lt acovatacg cette ATT 29 SAVEAS ie hha a Mee eA ee Mos Malle Bole Nas te Male A MEM ee
113. in program window It selects the passband either the unfiltered Broadband data or a 1 or 1 3 octave passband displayed on the impulse response plot The currently in use determines the available passbands The filter set is selected using the Filter Set spinner to the right of the plot in the main window Save This button opens a Save As file dialog box allowing you to save all of the intelligibility and acoustical values above to a standard ASCII text file suitable for import into a spreadsheet word processor or any other application that accepts ASCII files If you check the Save All Bands table in the Save As dialog the Intelligibility will automatically create a separate text file for each passband in the currently selected filter set SIA Smaart Acoustic Tools Version 4 User Guide Page 37 Chapter 2 Intelligibility Module Functions and Commands All Bands Table File Menu gt All Bands Table All Bands Table Keyboard Command Ctrl B This command opens the All Bands Table dialog box This window lists quantitative acoustical and intelligibility values for the broadband data and multiple octave or 1 3 octave depending on the filter set currently in use passbands The quantities listed in this table are all based on some combination of the level Ld Lr and Ln marker positions so only bands that have actually been displayed for the current file during the current Intelligibility module session will be inc
114. ion process you probably already have SIA Smaart Acoustic Tools up and running If not don t worry It is a very straightforward procedure All you need to do is start the automated installer program and follow the on screen instructions We strongly recommend that you close all other Windows programs particularly any automatic anti virus and or system monitor software you have running before attempting to install this software With Microsoft Windows running place the SmaartLive SIA Smaart Acoustic Tools installation CD in your CD ROM drive The CD menu program should open automati cally If the CD menu did not start automatically or you exited to shut down your virus checker double click the My Computer icon on the Windows desktop then right click the icon for the CD and select AutoPlay from the pop up menu After the CD menu program opens select Instal Smaart from the top level menu then click Smaart Acoustic Tools in the submenu When the Welcome screen of the install wizard appears click the Vext button to continue On the next screen select Install the Full Version Serial Number Required and click Next Enter your assigned Install Name and Serial Number on the next screen Please note that both your nstall Name and Serial Number must be entered exactly as registered You should have received a registration card in the package with this manual confirming the nstall Name and Serial Number assigned for your copy of Smaart Acoustic
115. is module s factory defaults SIA Smaart Acoustic Tools Version 4 User Guide Page 99 Chapter 3 Analysis Module Functions and Commands Mouse Procedures Most Analysis module functions can be accessed several different ways e g menu commands on screen controls or hot keys Some of these also have mouse short cuts and there are a few functions that can only be accessed using your mouse or other pointing device This section details the Analysis module s most important mouse procedures and shortcuts e Time Range Selection Time Display Time Slice and Spectrograph modes Select Change First FFT Center Point Time Display mode only e Select Normalization Point for Rainbow Display Time Slice mode only e Manual Delta Decay Rate Calculation Time Slice and Time Display modes e FFT Frame Selection Frequency Slice mode only e Masking Frequency Slice mode Time Range Selection In Time Display Time Slice and Spectrograph modes the main plot can display the entire wave file time range or any portion thereof Vertical Range Locator bars in the Waveform display show the boundaries of the time range currently displayed To select a specific portion of the time range for display using your mouse place the mouse cursor over the point on the plot in the Waveform display where you want the displayed range to begin and hold down the left mouse button 38 6 38 6 zz 54 4 0 000 0 250 0 000 0 250 0 000 38 6
116. ity Module Functions and Commands The time and amplitude difference between the Lr and Ln markers as well as the distance the time difference represents the S ope in dB second and the equivalent RT60 reverberation time are normally displayed in the slope readout and relative cursor readout fields above the plot Note that you can find this same information for any two points on the plot by holding down the Shift key as you click and drag move the mouse while holding down the left mouse button the mouse cursor across the plot to draw a line While the line is present the information in the slope readout and relative cursor readout fields is calculated relative to the end points of the line rather than the Lr and Ln markers Clicking once on the plot while holding down the Shift key erases the line See Finding Time and Amplitude Differences on page 24 for more details The All Bands Table All Bands Table After positioning the level markers for the passbands you want analyze you can click the A Bands Table button to display a table of reverberation and decay characteristic Clarity values and ALCons if applicable for multiple octave or 1 3 octave pass bands The A I Bands Table will include all bands in the current filter set that have been displayed since the current file was opened All Bands Table x DTR Alcons S lt Alcons L g The ntelligibility dialog box and the A I Bands Table both have a
117. l for a specified period of time after the level drops e Hold Peak For Specifies the length of time in seconds the meters hold peak levels when Peak Hold see above is enabled Meter Colors The input level meters in the Record dialog are designed to display three colors the normal LED color Light Green for input 0 and Light Blue for input 1 when the default Color Scheme is used plus Yellow and Red The meter LEDs will display input levels in the normal LED color up to the amplitude threshold specified for Yellow then Yellow up to the threshold for Red and Red above that level e Yellow if above Sets the amplitude threshold at which the meter LED color changes to Yellow e Red if above Sets the amplitude threshold above which the meter LED color changes to Red Appearance Meter Options for the appearance of the area immediately surrounding the meters e Raised The meter area will appear to protrude from the background e Inset The meter area will appear to be sunken into the background e Flat The meter area will be indistinguishable from the background Page 92 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands LEDs Options for the appearance of the meter LEDs e Raised The meter area will appear to protrude from the background e Inset The meter area will appear to be sunken into the background LED Levels The Anal
118. ld be required for the signal to decay 60 decibels at the given rate of decay Direct to Reverb The direct to reverberant level This is the relative difference between the level of direct sound to the level of reverberant energy at the top of the reverberant decay slope This value given in decibels is simply the difference in level between the Ld and Lr markers however it is an important factor in the overall intelligi bility of a room system Page 14 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands Clarity The Clarity field sets the number of milliseconds used for the Clarity Factor scale in the upper portion of the window For example entering 35 in this field will set the clarity scale to C35 STI and RSTI The STI and RSTI fields show the calculated Speech Transmission Index values after running the Calculate STI and RSTI routine Note that STI and RSTI values are calculated only when you click the Calculate STI and RSTI button These calculations can take some time to process particularly on long files so they are done only on demand This only needs to be done once for any file however The STI and RSTI values are not dependent on either the positions of the level Ld Lr and Ln markers or the passband currently selected for display Band The Band selector serves the same function as the Band selector to the right of the plot in the main program window It
119. lice and Spectrograph to the highest value actually found in the current wave file or the file displayed on top if two files are loaded e Calibrate to Full Scale Sets the 0 dB point for frequency based displays to the highest magnitude value theoretically obtainable given the wave file s sampling resolution 8 to 24 bits per sample e Calibrate to Custom Level Sets the 0 dB point for all frequency based displays to the level specified in the O dB field of the Custom Level section Custom magni tude values are specified as dB down from the theoretical maximum for the file s SIA Smaart Acoustic Tools Version 4 User Guide Page 89 Chapter 3 Analysis Module Functions and Commands sampling resolution 8 to 24 bits per sample e Set Custom Level To Current File Clicking this button plugs in the highest magnitude value actually found in the current wave file or the file currently displayed on top if two files are loaded as the O dB point for the custom calibration option Color Options Menu gt Color The SIA Smaart Analysis module allows you to customize the colors of virtually everything on the screen and even use your own bitmap files as a background Color and background options are loaded as sets called Color Schemes Several ready to use color schemes including two with metallic bitmapped backgrounds are included with the program and you can easily define your own The Colors tab of the Options
120. ll scale of the wave file based on bits per sample used to record the data Absolute Absolute Value Scaling uses a linear amplitude scale however the absolute value of each data point is plotted all negative values are converted to positive As with Linear scaling amplitude values are given as a percentage of the full scale of the wave file SIA Smaart Acoustic Tools Version 4 User Guide Page 59 0 5753 sec 644 4 28 78 dB In Time Display mode you can use your mouse to find time and amplitude difference between any two points on the plot Just drag the mouse hold down the left mouse button while moving across the plot to draw a line between the two points When you release the mouse button the difference between the end points of the line is displayed on the slope readout shown above located directly above and to the right of the Waveform Display To remove the line click once on the plot The units used in the Time Display cursor and slope readouts are user selectable You can choose to display any combination of time in seconds samples feet or meters by selecting the appropriate options on the Time Display tab of the options dialog box All distance values in the Analysis module are calculated from the Speed Of Sound value also set from Time Display options The default Speed Of Sound value is 1120 feet 341 35 meters per second The Time Slice Time Ss NN
121. log box to allow you to set title text and other options for the printout before proceeding with the selected operation The Custom Print Information dialog box includes all of the same options as the Printing tab of the Options dialog box If you un check this check box the Intelligibility will bypass the Custom Print Information dialog box in Print and Print Preview operations and execute the selected command immediately Page 52 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands Intelligibility Module Keyboard Shortcuts The following is a list of the Intelligibility keyboard commands hot keys Note that all of these commands are also available as menu commands and in some cases as on screen buttons or controls Key names on the list below are enclosed in brackets to differentiate them from descriptive text Some commands use more than one keystroke for example the accelerator key sequence to show hide the Schroeder Trace is Ctrl S This means you must hold down the Control key while you press the S key Display Decibel Scale Ctrl D Linear Scale Ctrl N Schroeder Trace S Schroeder Trace On Top Ctrl H ETC Ctrl E Intelligibility Graph Ctrl I All Bands Table Ctrl B File Open File Ctrl 0 Save As Ctrl S Record Impulse Ctrl R Create Impulse From File Ctrl F Print Ct
122. luded in the table Bands are added to the A Bands Table automatically as you change the passband for the main display and set or confirm the marker positions The All Bands Table lists from left to right the R760 Early Decay Time EDT Direct to Reverberant level DTR ALCons short S and long L forms for the 2 kHz octave band only the user selected Clarity factor Cn and additional Clarity values for 10 20 50 and 80 milliseconds C10 C20 C50 and C80 Note that the ntelligibil ity Graph can show you most of these same values with the exception of the last four Clarity columns for a single passband The A Bands Table provides an easy way to compare these values for different passbands Below the text table are three buttons labeled Print Save and Close Clicking the Print button will by default take you to the Custom Print Information dialog box to allow you to set title text and other options for the printout before printing If you have un checked Show this dialog before printing either in the Custom Print Information dialog box or the Printing tab of the Options dialog box the Print button will take you directly to the Print dialog box The Save button opens a Save As file dialog box to allow you to dump the information in the table to a standard ASCII text file suitable for import into a spreadsheet word processor or other application Note that the standard Windows file dialog box has been modified to allow
123. mand Ctrl F The Create Impulse From File feature allows you to acquire the impulse response of a system from recorded data You can use this feature to compare signals stored in two separate wave files or the Left and Right channels of a single stereo wave file Possible uses for this feature might include e Applications where you need to acquire data without a computer e Analyzing previously recorded data you already have on hand e Situations where the amplifier room or control room for a system is too far from the area you need to measure to return the measured signal to the computer Page 34 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands The Create Impulse From File function can use either the Dual FFT method or MLS to calculate an impulse response For the dual FFT method the choice of test signals can be very flexible For example you could use a segment of a track from a music CD a pink noise or other test signal track from a reference CD or a wave file sent through the system under test from a computer and then recorded remotely The only real requirements are that the measurement file or track must be recorded using the same signal used to create the reference file and that the signal used has enough energy at the frequencies you need to measure The reference file will be the dry signal as sent to the system under test The measurement file will be the same s
124. measure ment system itself i e the computer and sound hardware Also since the MLS stimulus signal is more white than pink noise you need to exercise greater care to avoid damaging the high frequency elements of loudspeaker systems under test Note that the MLS technique can be used with or without an external loopback on one audio I O channel as a time reference see diagram on page 18 Due to a limita tion of Microsoft Windows the loopback is required to accurately measure the delay time through the system under test when using MLS This loopback signal is used only as a time reference and should not be confused with the reference signal in Dual FFT measurements The Dual FFT Method The Dual FFT impulse recording technique is stimulus independent The Intelligibility module provides an internal pink noise generator for use with the Dual FFT impulse response recorder but virtually any continuous test signal generated inside or outside the computer may be used In a Dual FFT measurement a test signal is split prefer ably outside the computer with one branch returning directly to one computer audio Page 16 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands input as a reference The other branch is sent through the system under test and the output of the system is returned to a second computer audio input as the measure ment signal see diagrams on pages 20 and 21 Thes
125. measurement and the resulting wave file size Larger files will take more time to filter and analyze If you find you have overestimated when the measurement is completed you may want to use the X Zoom feature and Save As command to edit out some of the unneeded noise tail Page 22 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands Dual FFT Recording the Impulse Response If you are using the internal Pink Noise Generator click the Generate Pink Noise button to begin sending a signal and carefully bring the Leve control up to desired level Note that you may also need to set the overall Wave output level in the Win dows Volume Control to achieve the desired output level If you are using an externally generated signal start sending signal to the system under test and the computer In either case adjust appropriate external gain controls and or the computer s Line In level in the Windows Recording Control as necessary so that the reference signal is running at about 12 dB on the nput Meters Make sure the reference signal is being received on computer s Left input channel indicated by the blue meter LEDs on the right and the measurement signal from the microphone is on the Left input indicated by the green meter LEDs on the left Adjust the measurement microphone preamp gain if necessary so that both the reference and measurement signals are running at about 12
126. mes and frequency ranges in Frequency Slice and Time Slice modes respectively Note that you can also navigate between bands frames using the Band spinner that appears to the right of the main plot in Time Slice mode or the Frame spinner that replaces the Band spinner Frequency Slice mode Next Slice View Menu gt Amplitude gt Slice Keyboard Command Space Bar Moves the display to the next FFT frame or Time Slice depending on the current display mode Previous Slice View Menu gt Amplitude gt Slice Keyboard Command Shift Space Bar Moves the display to the previous FFT frame or Time Slice depending on the currently selected display type Go to Slice View Menu gt Amplitude gt Slice Keyboard Command Ctrl G In Frequency Slice mode this command opens a dialog box prompting you to select an FFT frame for display by time or frame number Mouse Shortcut You can select an FFT frame in Frequency Slice mode by placing the mouse cursor on a point in the Waveform Display and clicking the left mouse button Loop Through Slices View Menu gt Amplitude gt Slice The Loop through Slices command displays all of the FFT frames calculated for the wave file sequentially returning to the beginning of the file when it reaches the end Repeating the Loop through Slices command toggles the feature off SIA Smaart Acoustic Tools Version 4 User Guide Page 81 Chapter 3 Analysis Module Functions
127. module menu commands please refer to Analysis Module Commands beginning on page 68 File 1 Information cs A CI CON This section of the Analysis module window provides information about the primary wave file loaded in the Analysis module The Open File 7 button calls an Open file dialog box allowing you to select a wave file to load The next field to the right displays the file name of the wave file after opening it Immediately to the right of the file name field are two fields that display the number of samples in the file and the sampling rate and resolution bits sample at which the data was recorded Clicking on either of these two fields with your mouse will open the File Information dialog box see page 69 with additional details about the file s currently loaded When a stereo wave file is loaded the L and R channel buttons select which channel is displayed FFT Information The FFT information field immediately to the right of the File 7 information fields provides details about the frequency domain data calculated for the current wave file s by the Analysis module s Transform function see page 71 The values SIA Smaart Acoustic Tools Version 4 User Guide Page 55 Chapter 3 Analysis Module Functions and Commands displayed here include the FFT size in samples the overlap percentage and the frequency resolution of the FFT Clicking anywhere in this field calls the Transform dialog box to allow you to transfo
128. mp gain and or the computer s Line n level in the Windows Recording Control if necessary so that the measurement signal and loopback signal if applicable are running at about 12 dB on the Input Meters and click the Record button The Intelligibility module will record audio data based on you measurement parameters process the data and write the results to the specified output file When the recording process is completed the Record Impulse dialog box closes automatically and the new file is displayed in the main Plot Area Recording an Impulse Response Using Dual FFT The Dual FFT impulse response measurement technique is stimulus independent This technique can be used with internally or externally generated pink noise recommended for most acoustical measurement applications or virtually any other continuous signal e g music as a stimulus Measurement Microphone Loudspeaker System Under Test Preamp Amplifier Phantom Power Supply Reference Signal Dual FFT measurement setup using the internal signal generator requires full duplex capable computer sound hardware Page 20 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands When using this recording method a test signal is split normally outside the com puter with one branch returning directly to one computer audio input as a reference signal The other branch is sent through the system under test and t
129. mpulse response data and includes tools to help you find reflections reverberation and decay information Other possible uses for this program include speech analysis or any application where you need to analyze the time and frequency characteristics of recorded signals What s New In this Release SIA Smaart Acoustic Tools 4 features a completely redesigned user interface for both the Intelligibility and Analysis modules The new interface design is intended to dramatically increase ease of use by reducing the complexity of on screen control surfaces providing easier access to the most frequently used program features and making data readouts larger and easier to read Several redundancies and inconsis tencies in the two program modules have also been addressed In the Analysis module the Analyze function has been removed since the All Bands Table in the Intelligibility module provides very similar functionality The Intelligibility module also uses more conventional methods of finding and calculating quantitative acoustical values and produces more consistent and reliable results In the Intelligibility module a stock set of Clarity Factor calculations for 10 20 50 and 80 milliseconds have been added to the All Bands Table to compensate for the removal of the Analyze function from the Analysis module The ExSTI calculation has been removed since the program also calculates true STI and RSTI values and ExSTI is not a widely used or
130. mpulse response recorder that can calculate and record the impulse response of the system under test using either a Maximum Length Sequence MLS or stimulus independent dual Fast Fourier Transform FFT transfer function technique The MLS method requires the use of an internally generated MLS stimulus signal The Dual FFT method can use pink noise or virtually any other continuous signal e g music as a stimulus this is the same technique used in SIA SmaartLive to find delay times The Intelligibility module provides an internal pink noise generator for use in dual FFT measurements however externally generated signals may be used as well The Intelligibility module can also be used to analyze impulse data from any other source as long as the data is stored in or can be con verted to standard Windows wave files continued The SIA Smaart Analysis Module The Analysis module reads audio data stored in any standard Windows wave wav file including impulse response files recorded in the Intelligibility module The program can open one or two wave files at a time and can transform time domain data in the wave file s into its frequency domain representation using a series of Fast Fourier Transform FFT calculations Both time and frequency characteristics of recorded signals can then be displayed compared and analyzed a number of ways Like the Intelligibility module the Analysis module is primarily designed for use in analyzing i
131. nd opens a standard Windows Print Setup dialog box where you can select a printer and set up the page size orientation and paper source for hard copy output Depending on the type of printer selected there may be additional options you can access by clicking the Properties button in the Print Setup dialog Page 40 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands View Menu Commands Zoom Zoom Out To Limits View Menu gt Zoom gt Zoom Out To Limits Keyboard Command Home This command returns the time x axis range of the main plot to the full time range of the wave file and resets the amplitude y axis range to the default range as specified on the Graph tab of the Options dialog box A shortcut for this command is to simply click once with your mouse anywhere outside the plot in the margins of the plot area Undo Redo Zoom View Menu gt Zoom gt Undo Redo Zoom Keyboard Commands Undo Zoom Ctrl Z Undo Zoom Ctrl A As you zoom in and out on the main plot the Intelligibility module remembers each zoom view and allows you to browse back and forth through the previous views using these two commands Zoom X In Out View Menu gt Zoom gt Zoom X In Out Keyboard Commands Zoom X In Ctrl Down Arrow Zoom X Out Ctrl Up Arrow These two commands increase or decrease the horizontal x axis magnification by decreasing t
132. ndividual sections of the vertical bars are plotted e Uniform This option displays the Spectrograph as a continuous color map with each vertical bar having a uniform width from top to bottom e Relative Varies the horizontal widths of individual sections in the vertical bars plotted re ative to their magnitude value higher magnitude values are wider Colors e Dynamic Range This value sets the magnitude range included in the file based Spectrograph display only All magnitude values in the Spectrograph display are given as dB down from zero so specifying a dynamic range of 50 plots a magni tude range from 0 dB to 50 dB e Number Selects the number of colors to use in the Spectrograph plot from 8 to 236 depending on your display hardware and drivers This setting along with the Dynamic Range also determines the number of decibels represented by each color e Min Selects the color used to represent the minimum magnitude value s shown on the Spectrograph plot Clicking the colored square opens a standard Windows Color dialog box enabling you to choose a different color for the lowest value s e Max Selects the color used to represent the maximum magnitude values shown on the Spectrograph plot Clicking on the colored square opens a standard Window Color dialog box enabling you to choose a different color for the highest value s Default The Default button resets the Min and Max color selection
133. neral Rule The higher the data sampling rate the higher the frequency content of the digitized signal However higher sampling rates also mean more data to be calculated and possibly stored in a given period of time Transfer Function The transfer function is a complex comparison of two signals typically a reference signal and a measurement signal Most commonly this comparison is made between the input and output of a device or system such as an equalizer sound system or room When recording an impulse response measurement using the Dual FFT method the SIA Smaart Intelligibility module records two channels of audio data transforms the data using FFTs and calculates the transfer function of the two input signals in the frequency domain The results of the transfer function calculation are then transformed using an inverse FFT and displayed in the time domain to show the impulse response of the device or system under test Page 114 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 4 Reference Glossary of Audio and Acoustics Terms Analog to Digital A D Conversion The process of digitizing an analog signal This process almost always involves limiting the frequency content of the digitized signal Absolute Value For any real number the Absolute Value is the unsigned magnitude of the number Example the absolute value of 3 denoted 3 3 Amplitude The size of a real number e g a number of volts in either
134. nformation please refer to The Spectrograph on page 64 Channel View Menu gt Channel EE When a stereo wave file is open in the Analysis module the Channel commands select which channel Left or Right is displayed If two stereo files are loaded the displayed channel for each file is selected independently the Channel commands apply to the wave file displayed on top To view both channels of a stereo wave file simultaneously open the same file as both File 1 and File 2 then select the Right channel on one copy and the Left channel on the other Time Zoom Move Right Left View Menu gt Time Zoom gt Move Right Left Keyboard Commands Move Right Right Arrow Move Left Left Arrow When you are zoomed in on the horizontal x axis range of the main plot only a portion of the wave file s full time range is displayed These two commands move the displayed range left or right to allow you to view the information before or after the range currently displayed Page 78 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands Zoom In Out View Menu gt Time Zoom gt Zoom In Out Keyboard Commands Zoom In Ctrl Down Arrow Zoom Out Ctrl Up Arrow These two commands increase or decrease the horizontal x axis magnification of the Time Display Time Slice and Spectrograph plots by decreasing the displayed time range of the main plot Note that wh
135. nternal signal generator as your stimulus signal source SIA Smaart Acoustic Tools makes no use of the sound hardware s synthesis capability if any For our purposes the major differentiating factors between sound hardware are the maximum sampling rate sampling resolution bits per sample and signal to noise S N ratio If your computer does not have sound hardware lacks a line level input or you feel that ts existing hardware may be problematic for any other reason there are a number of add on computer sound devices on the market that you can utilize for audio input and output When selecting an aftermarket sound hardware device for use with SIA Smaart we recommend you look for the following features and audio characteristics e Full duplex simultaneous play and record capability e 2 independent external line level input channels e 16 to 24 bit sample resolution e Digital inputs for use with external A D converters optional but highly recommended e User selectable sampling rates The Smaart Intelligibility module supports a number of different sampling rates from 5512 up to 48 kHz We recommend choosing a sound card which supports the 44 1 and or 48 kHz sampling rates and at east one additional sampling rate somewhere in the range between 4 kHz and 12 kHz Page 2 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 1 Getting Started External Hardware In addition to your computer and SIA Smaart Acoustic Tools
136. o Default 39 Options Menu Intelligibility Module 47 Color 47 Devices 48 Graph 49 Meter 50 Printing 52 View Menu Intelligibility Module 31 1 3 Octave Band Filters 46 Amplitude 43 Channel 46 Marker Ld Lr Ln 45 46 Octave Band Filters 46 Show 43 44 45 46 Track Nearest Data Point 46 Zoom 41 Page 128 SIA Smaart Acoustic Tools Version 4 User Guide Intelligibility Module Filters 25 Intelligibility Module Functions 10 Calculating Intelligibility 10 Filters 25 Intelligibility Graph 13 Positioning the Ld Lr and Ln Markers 25 Recording an Impulse Response 15 Zooming With the Mouse 25 Intelligibility Module Window 6 J Jumping to Other Programs 9 26 K Keyboard Shortcuts Analysis Module 104 Intelligibility Module 53 L Latency 116 Ld Lrand Ln 10 Led Levels 93 Linear amp Logarithmic Scales 111 Linear and Logarithmic Scales 111 Linear Scale 116 Links to Other Programs 9 26 Logarithmic Scale 116 Loop Through Slices 81 Loopback 33 Magnitude 116 Making a Screen Capture 28 Marker Ld Lr Ln 45 Mask 83 84 Clear Mask 84 Maximum Length Sequence MLS 111 Measurement Channel 34 Measurement Microphone 3 Measurement Setup Diagram Dual FFT External Signal Source 21 Internal Signal Generator 20 MLS 18 Menu Bar 7 Meter Options 50 Meters 92 Minimum Configuration 1 Mixer or other level adjustment device 3 MLS 15 17 34 111 MLS Length 34 MLS Measurement Setup 18 MLS Signal Generator 33 MLS Reco
137. o wave files both must be transformed using identical transform parameters When two files are loaded transforming File 7 will automatically transform File 2 using the same param eters and the frequency domain information for File 2 is stored in a temporary file If File 1 has already been transformed selecting Time Slice or Frequency Slice mode automatically transforms File 2 only using the same parameters as were previously used file for File 1 Note that the Spectrograph display mode and the Rainbow display in Time Slice mode are not available when two files are loaded SIA Smaart Acoustic Tools Version 4 User Guide Page 67 Chapter 3 Analysis Module Functions and Commands Analysis Module Commands File Menu Commands Open File 1 File Menu gt Open File 1 Keyboard Command Ctrl 0 coo MECANO I AT This command calls the Open file dialog box allowing you to select a standard Windows audio waveform wav file also called a wave file to be opened for analysis This dialog box is modified to show the sampling rate resolution 8 to 24 bit type stereo or monaural and the length in samples and seconds of the file you select When a wave file is opened the Waveform Display and Time Display plots appear If a stereo file is loaded only one channel is displayed You can switch between channels using the and A left right channel selector buttons Close File 1 File Menu gt Close File 1 Cl
138. oe E S o A Fo tic The Ti ad A AAA eoa e Time Slice display IS MERA E 5 J meo tne ste similar to the Time Display in that it plots time on the x axis aaa et vs magnitude on the y axis Dee however there are a couple of up g important differences First El am s 5 Banding T the time slice shows you data N al for only a narrow frequency ee range Bandwidth options N available for this display mode are Narrowband Octave or 1 3 Octave The other big difference may be less obvious but in Time Slice mode you are actually looking at FFT data instead of the raw time domain audio data shown in the Time Display This is why the Time Slice trace appears much smoother than the band limited time domain displays in the Intelligibil ity module Time domain displays plot one data point for each sample in the wave file whereas on the Time Slice plot there is one data point for each FFT frame Page 60 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands The time resolution of the Time Slice plot as well as the bandwidth of the Narrowband Time Slice display is determined by the frequency resolution of the FFT size selected when the wave file is transformed Band 500 0 Hz E Ei The current center frequency and bandwidth are shown on the Band and Banding spinners that appear to the Right of the plot in Time Slice mode The center frequency the Time Slice
139. of the main Intelligibility module program window The ETC display mode can be useful in identifying reflections and looking at the decay characteristics of a system under test Although the ETC plot does resemble the impulse response plot displayed ona decibel scale it can make discreet reflections in particular somewhat more promi nent and easier to see Note that a number of program features are disabled in ETC display mode For example the ETC cannot be used as the basis for the intelligibility calculations and linear amplitude scaling is not applicable to this type of display ETC is a toggle command Clicking the same button or selecting the same menu command again will restore the standard impulse response plot Page 44 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands Marker Ld Lr Ln View Menu gt Marker Ld Lr Ln The Marker Ld Lr Ln sub menu commands allow you to select and position the level markers using keyboard or menu commands Note that you can also select markers by simply clicking them with your mouse and move the markers around on the plot by clicking and dragging them moving the mouse while holding down the left mouse button from one place to another Or to snap the selected marker to the mouse cursor location hold down the Alt and click the left mouse button once Select Next Marker Keyboard Command Tab Cycles marker selection
140. of the sample to be transformed Decay Rate The rate at which a signal decays diminishes in magnitude usually a function of frequency and expressed in either decibels per second or relative to the amount of time that would be required for the signal to decay 60 decibels at the given rate of decay see Reverberation Time SIA Smaart Acoustic Tools Version 4 User Guide Page 115 Chapter 4 Reference Decibel The decibel often abbreviated as dB is a logarithmic ratio between two values In acoustics decibels most commonly refer to the ratio of an input level to the output level of a system or a given level compared to a fixed reference Dynamic Range The difference in level between the highest and lowest signal a system can accept or reproduce Early Decay Time EDT An acoustical quantity which is the time required for a system typically a room to complete the earliest stage of its decay typically the first 10 decibels The Early Decay Rate can be expressed in units of decibels per second or relative to the amount of time that would be required for the signal to decay 60 decibels at the given rate of decay FFT The Fast Fourier Transform is a mathematical technique used to transform time domain data into the frequency domain The term Fast refers to the fact that when the number of time domain samples is a power of 2 16 32 64 128 256 et al the calculations can be performed very quickly by a digital computer
141. of the three Title fields is left blank that line is omitted on the printed page SIA Smaart Acoustic Tools Version 4 User Guide Page 93 Chapter 3 Analysis Module Functions and Commands Footer Note 1 and 2 You can specify up to two lines of footer text to appear at the bottom Analysis Module printouts If either of the Note fields is left blank that line is omitted on the printed page Print Today s Date If this box is checked the current date as set on your computer will be inserted in the title area at the top of the printout If you want to use a date other the current system date of your computer on the printout un check this box and type the desired date as one of the Title lines Note In addition to the note and date lines as specified in the Footer section above Analysis Module printouts will also include a final footer line with the notation Created by User Name using SIA Smaart The User Name will be the name of the user to whom this copy of Smaart Acoustic Tools is registered This line cannot be edited or omitted e Show custom print dialog before print and print preview When this box is checked selecting eitherthe or commands will open the Custom Print Information dialog box to allow you to set title text and other options for the printout before proceeding with the selected operation The Custom Print Information dialog box includes all of the same options as the Printing tab of the Options
142. om As and ASCII Save commands Also the tracking cursor always tracks along the top trace when Track Data is enabled Adjusting the File 2 Time Offset When two files are loaded the maximum displayable time range will be equal to the length of File 1 If File 2 is longer its time range is truncated To adjust the time position of File 2 for example to align peaks in the two traces use the keyboard commands below These commands are available only in Time Display mode Fine Adjustment e Hold down the Ctrl key while pressing the Left Arrow to move the File 2 trace one pixel to the left e Ctrl Right Arrow moves the File 2 trace one pixel to the right Page 66 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands Coarse Adjustment e Ctrl Shift Left Arrow moves File 2 left in larger increments e Ctrl Shift Right Arrow moves File 2 right in larger increments Clear File 2 Time Offset e Ctrl R removes all time offset Note You can also specify the File 2 offset in samples in the File Information dialog box To open the File Information dialog select File Info from the File menu or click either of the two fields immediately to the right of the file name readout for File 7 where the number of samples sampling rate and resolution for the file are displayed Transforming File 2 Before the Analysis module can display frequency information for the tw
143. ommand labeled Excel in the jump menu for the Intelligibility or Analysis module if added to wrjumps txt and imjumps txt When selected from the jump menu this command would open MicroSoft Excel and load the last ASCII text file saved by the program into a new Excel worksheet Excel PATH c Program Files Microsoft Office Office Excel exe ARGS EXIT N SMAART N WAVE N TEXT Y Each jump must begin with a section title enclosed in brackets that will also become provides the text label for its jump menu command in Intelligibility or Analysis module pop up jump menu The PATH line must provide the complete path and file name of the target program The ARGS line can be used to pass additional command line arguments to the target application if necessary The remaining lines are yes or no questions that should have either a Y or N after the equals sign as follows e If EXIT Y the Smaart program you are jumping from shuts down as it starts the target program The SMAART line is for use when jumping between Smaart Acoustic Tools and SmaartLive 4 1 or higher and should be set to N for jumps to other programs e If WAVE Y the Smaart program you are jumping from will pass a wave file it has open File 1 only in the Analysis module to the target application This line should be set to N if the TEXT line is set to Y e If TEXT Y the last text file saved by the Smaart program you are jumping from
144. onsidered good 12 to 4 percent are fair below 12 is considered poor Clarity Factor Cn The acoustical quantity of Clarity is the ratio of the early sound to late sound The division between early and late sound is given in milliseconds and expressed as Cn where n is a number of milliseconds e g C10 C20 C50 etc For example C50 is a decibel energy ratio of the sound arriving within 50 milliseconds of the direct sound compared to the overall reverberant decay This tends to be one fairly accurate predictor of subjective intelligibility Clarity values above 5 are considered good 2 to 5 is fair values below 2 are considered poor The default Clarity factor for the Intelligibility module is C50 Other commonly used Clarity factors include C35 and C7 You can change the Clarity factor to anything you like by a by changing the number of milliseconds in the Clarity field on the Graph tab of the Options dialog box Page 106 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 4 Reference Data Window Functions Data Window functions help to reduce truncation errors arising from the segmenting of longer data series into FFT frames Remember that the Fast Fourier Transform FFT requires a data series of finite length The value of the samples immediately before and after the data series used in the FFT are unknown and this can lead to certain anomalies in the Fourier transform results All data windows types operate under th
145. orandom noise generated using a system of bit shift registers and a known group of seed numbers An MLS sequence is almost always a power of 2 64 128 256 512 samples in length however this is not an absolute requirement One attractive feature of MLS is that it is repeatable noise Starting with the same seed numbers the same exact sequence can be generated any number of times Also when an MLS sequence or string of MLS sequences is played through a system under test and the results recorded the measured results and the MLS seed numbers can be entered into a calculation called the Hadamard transform to calculate the impulse response of the very efficiently SIA Smaart Acoustic Tools Version 4 User Guide Page 111 Chapter 4 Reference Octave Band Resolution Octave band resolution provides a combination of logarithmic and linear frequency scales On this type of display each octave is represented as an equal width along the frequency axis This correlates with human hearing where each octave appears to sound like an equal interval even though the number of Hertz doubles between each increasing octave In SIA Smaart octave band values are derived from FFT data The lowest bands appear as ghosted images or are not shown when the frequency resolution is insufficient for the data to be reliable see Frequency Resolution Octave and fractional octave resolution plots are often simpler to read than narrow band frequency d
146. oser to the end of the measurement than the beginning appearing to indicate an unbelievably long delay time through the system under test There are two likely causes for this problem 1 The computer input channels are wired incorrectly and need to be swapped 2 There is a delay in the reference channel In the first case swapping the inputs to the computer will correct the problem In the second case you must either compensate for or remove the delay in the reference channel To accomplish this you could delay the measurement signal by an equal amount using an external delay device or simply remove the device s introducing delay from the reference signal path Digital signal processing devices are likely suspects for reference signal delay For example many digital delay units introduce some delay even when setto bypass and or indicating O ms delay time This is called atency or throughput delay Other types of digital audio devices may also introduce unwanted delay Printing Problems Problems with printing from SIA Smaart applications often turn out to be the fault of incorrect outdated or corrupt printer drivers If you have printing problems make sure you have the correct Windows software driver for your printer properly installed and configured If necessary reinstall the drivers from the Windows setup disk s or disk supplied with your printer using the Windows Printers control panel If problems still persist check
147. oses the wave file If two files are loaded this command closes both Open File 2 File Menu gt Open File 2 Keyboard Command Ctrl Shift 0 il Top Trace L R noz MTT Jasso samples eree This command calls an Open file dialog box allowing you to select a second wave file to be loaded for comparison with the first File 2 must be of the same type monaural or stereo sampling rate and resolution bits per sample as File 1 The data from the second file is plotted in a different trace color By default the second file is displayed on top of File 1 in the z axis stacking order In other words the File 2 trace will cover the File 1 trace both in the Waveform Display and on the main Time Display plot anywhere the two traces overlap To bring the File 1 trace back to the top click the Top Trace button Clicking this button again brings File 2 Page 68 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands back to the top and so on The file displayed on top is the object of all commands that act only on one file at a time such as the Channel selection for stereo files Save Wave Zoom As and ASCII Save commands Also the precision cursor always tracks along the top trace when Track Data is enabled Note By loading the same stereo wave file as both File 1 and File 2 you can use this feature to view both channels of the file simultaneously Close File 2 File Menu gt Close
148. ot directly editable as it is a function of the selected FFT size and Sampling Rate FFT Size divided by Sampling Rate FFT Time Constant It is very critical that the FFT Time Constant be longer than the total decay time of the room system under test Page 32 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands The MLS Tab DualFFT MLS The MLS recording method is a single channel E stimulus dependent measurement technique that Levet 2424 Generate Channel s Stereo z compares the measured data to an MLS data 7 i Generate MLS Signal sequence stored internally The measurement E Impulse Output File parameters for MLS recording are substantially fan tesi mor cout tols sites wo ll Browse similar those for the Dual FFT Method but the Pt ee emt 8 itr 7 Reference Channel Right F Clip r MLS tab has a few additional options faa rar MLS Signal Generator The use of the internal ic 41 4 SR 44100 y signal generator is again optional but in the case E 4 of MLS it is the simplest way to ensure that the ie at re 44 E op stimulus signal exactly matches the internal MLS data used in calculating the impulse response of the system under test The MLS Signal Generator Core section includes a Level selector that sets the output gain in dB a Generate Channel s selector used to set the output channel s and a Generate MLS Signal button that starts and stops the
149. ove The default speed of sound value is 1120 feet per second or 341 359 meters per second Page 98 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands Waveform Options Menu gt Waveform The Waveform tab of the Options dialog box contains the following options for controlling the amplitude range of the Waveform Display Amplitude Zoom e None Displays an amplitude range representing 100 of the maximum possible amplitude given the wave file s digital resolution 127 for an 8 bit file 32 k for a 16 bit file e Peak to Peak This option scales the y axis scale of the Waveform Display equal to the largest amplitude values actually encountered in File 1 Custom Allows you to set a custom amplitude range for the Waveform Display using the two edit fields The minimum Min and maximum Max values for the amplitude range are specified as a percentage of the maximum amplitude values possible given the wave file s digital resolution Default On Open e None Selects None full scale as the start up default amplitude scaling for the Waveform Display e Peak to Peak Selects Peak to Peak see above as the start up default ampli tude scaling for the Waveform Display Set All Options to Default Options Menu gt Waveform Returns all user configurable settings with the exception ofthe Color Scheme and Device selections to the Analys
150. pling rate supported by the CD or DAT recorder For best results use a digital recording device to record the output of the system under test If you plan to bring the measured signal back into the computer digitally it should be recorded at the same sampling rate used to generate the MLS stimulus signal If you will be bringing the signal back in through an analog input it should be SIA Smaart Acoustic Tools Version 4 User Guide Page 35 Chapter 2 Intelligibility Module Functions and Commands recorded at the same sampling rate or higher In either case the measurement wave file should be recorded at the same sampling rate as the original stimulus signal If all this is starting to sound too complicated don t worry You can also obtain very good measurement results using MLS data with the dual FFT technique All you need is a wave file with the original MLS signal recorded at the same sampling rate and resolution as the measurement data file Intelligibility Graph File Menu gt Intelligibility Graph Intelligibility Keyboard Command Ctrl I This command opens the Intelligibility dialog box where the results of all intelligibility calculations the Intelligibility module supports are displayed This dialog box is mode less meaning you can leave it open while you continue to work in the main program window Changes to the marker positions on the main plot are applied to the calculated values automatically where
151. r is normally positioned directly on the this peak clicking the Peak button to the left of the Ld field will return it to the peak position it is moved The larger field on the right is a readout for either the pencil tool see page 24 or the relationship between the Lr and Ln markers When a line is drawn on the plot with the pencil tool this field displays the time and amplitude difference between the end points of the line as well as the distance the time difference represents When the normal impulse response plot is displayed and no line is present the readout area displays the time and amplitude difference between the Lr and Ln markers Cursor Readout The readout field immediately above the main plot area on the left gives you x and y axis coordinates for the Intelligibility module s precision tracking cursor when the mouse cursor is positioned over the main plot area X axis coordinates are given in seconds and distance relative to the beginning of the file Y axis coordinates are given as decibels dB for the ETC and impulse plot when Logarithmic amplitude scaling is selected or as percentage of full scale based on the bits per sample at which the wave file was recorded for Linear scaling Slope Readout The S ope field immediately above the main plot to the right of the tracking cursor readout see above is a readout for either the pencil tool see page 24 or relationship between the Lr and Ln markers in dB scaling mode only Wh
152. rd to be a power of 2 samples in length For long files and real time operations SIA Smaart will do the frequency domain transformation in pieces frames each a power of 2 samples in length Note It is certainly possible to calculate the Fourier Transform for a time record with any number of samples But when the number of samples is not a power of 2 the number of calculations required can become very large Ona PC this could result in a very slow Fourier Transform Frequency Resolution The frequency resolution of an FFT is calculated from the sampling rate and FFT size For a given FFT size the frequency resolution of the FFT will be equal to the sampling rate divided by 2 the Nyquist frequency divided by half the FFT size This means that the data points along a frequency plot are distributed evenly along the frequency axis every 0 Hertz where Q is the frequency resolution For example sampling at 44 100 Hz gives you a Nyquist frequency of 22 050 Hz An FFT size of 1024 yields 512 frequency data points Divide 22 050 by 512 to get a frequency resolution of 43 07 Hz This means that there is one data point every 43 07 Hz SIA Smaart Acoustic Tools Version 4 User Guide Page 109 Chapter 4 Reference The table below shows frequency resolutions for some typical sampling rates and FFT sizes Sampling Rate FFT size in samples Frequency Resolution 44100 Hz 2048 21 5 Hz 44100 Hz 1024 43 0 Hz 22050 Hz 2048 10 7 Hz
153. rding the Impulse Response 20 MLS Setting Measurement Parameters 18 Mouse Procedures 100 Move FFT Center Left 86 Move FFT Center Right 86 Move Range Left Right 42 Move Range Up Down 42 Move Up Down 80 Next Slice 81 Normalized 88 Nyquist Frequency 116 0 Octave 1 3 Octave Band Filters 46 Octave Band Filters 46 Octave Band Resolution 112 116 117 Open 29 Open File 1 68 Open File 2 68 Options See Options Menu Commands Options dialog box 89 Options Menu All 47 48 49 50 52 Color 47 Devices 48 Graph 49 Meter 50 Printing 52 Overlap 117 SIA Smaart Acoustic Tools Version 4 User Guide Page 129 P Parametric Equalizer 117 Phase Shift 117 Pink and White Noise 112 Pink Noise 117 Pink Noise Generator 31 Plot Title 49 Positioning the Ld Lr and Ln Markers 24 Power Spectrum 63 88 93 94 Print 39 73 Print Command 73 Print Preview 39 40 73 74 Print Setup 40 74 Printing 39 40 52 74 93 Print Command 39 Print Preview 40 74 Print Setup 40 74 Printing Options 52 93 Printing Problems 124 Propagation Delay 117 Rainbow 87 Rainbow Display Normalized 88 Range 25 41 42 43 49 Recommended Configuration 1 Record Impulse 30 Recording 15 17 20 Recording an Impulse Response 15 Recording an Impulse Response Using Dual FFT 20 Recording an Impulse Response Using MLS 17 Recording the Impulse Response Dual FFT 23 MLS 20 Reference Channel 33 Reset to No Shift 84 Restoring the Default Configurations 125 R
154. rement the MLS time constant must be longer than the decay time of the system under test As a general rule a time window of 7 to 1 5 seconds is sufficient for most small to mid sized rooms Larger rooms with longer decay times require a longer time window When in doubt it never hurts to go too long in fact it will help to improve the signal to noise ratio of the measurement This does however increase both the time required to make the measurement and the resulting wave file size Larger files will take more time to filter and analyze If you find you have overestimated when the measurement is completed you may want to use the X Zoom feature and Save As command to edit out some of the unneeded noise tail SIA Smaart Acoustic Tools Version 4 User Guide Page 19 Chapter 2 Intelligibility Module Functions and Commands MLS Recording the Impulse Response If you are using the internal MLS Signal Generator click the Generate MLS Signal button to begin sending a signal and carefully bring the Leve control up to desired signal level Remember that the MLS signal is essentially white noise with most of its energy in the higher octaves You need to exercise care not to overdrive high frequency drivers in the loudspeaker system being used to stimulate the room Note that you may also need to set the overall Wave output level in the Windows Volume Control to achieve the desired output level Adjust the measurement microphone prea
155. rl P Marker Ld Lr Ln Move Selected Level Ld Lr Ln Marker Arrow Keys Up Down Left Right Select Next Level Marker Tab Set Ld Marker To Peak Shift P Options All Options Alt 0 Graph Options Alt G Zoom and Range Undo Zoom Ctrl Z Redo Zoom Ctrl A Zoom Out To Limits Home Zoom X In Ctrl Down Arrow Zoom X Out Ctrl Up Arrow Move Range Left Ctrl Left Arrow Move Range Right Ctrl Right Arrow Zoom Y In Zoom Y Out Move Range Up Page Up Move Range Right Page Up SIA Smaart Acoustic Tools Version 4 User Guide Page 53 Chapter 3 Analysis Module Functions and Commands Chapter 3 Analysis Module Functions and Commands Navigating in the Analysis Module Ez Room wav SIA Smaart Analysis Module Of x File Audio View Options Help Mr RT NY i EI Peo ctic Foot room fonos sanne A 10 4393 sec 60 48 dB 0 5753 sec 644 4 28 78 dB Time Disp Time Slice tro Freq Slice j m i 0 250 i Transform Options Sample Range Amplitude dB Amplitude Scale Log dB v 0 500 Time sec Like the Intelligibility module the Acoustic Tools Analysis has a completely rede signed user interface that speeds access to the most frequently used program functions Again simply the clicking the label or readout field for an on screen control or readout will allow you to
156. rm or re transform the wave file data for the Analysis module s frequency based displays File 2 Information i Top Trace L R rez Room2 wav 44486 samples el This section provides information about a second wave file loaded in the Analysis module The Open File 2 button calls an Open file dialog box allowing you to select a wave file to load The next field to the right displays the file name of the wave file after opening it Clicking this field with your mouse pops up a menu that will allow you to close the second wave file or select another file to open as File 2 Immediately to the right of the File 2 file name field is a field that displays the number of samples in the file the sampling rate and bits sample for File 2 must be identical to File 1 Clicking on this field with your mouse will open the File Information dialog box see page 69 with additional details about both files currently loaded The Top Trace button cycles the z axis stacking order in multiple trace displays If File 2 is a stereo wave file the L and R Channel buttons select which channel is displayed Audio Controls Rec Play Pause Stop The Audio controls provide access to the Analysis module s Record function and the means to start pause and stop audio playback of an open wave file When two files are loaded the file currently displayed it front will be played For more information see Audio Menu Commands beginning on page 75 Tracking Cursor
157. rve EMC cion cc 108 Fast Fourier Transtorini FET airada 109 Frequency ReSOIUtion rassier aiaeeiiee arinaa anina daan Ea eanan da Sainan andaa nia ainaani an tannins 109 Impulse Response vais fn cake bhai do 110 Linear and Logarithmic Scales cccecsccsessesseeseteeeeeeseseeeeecaeseeeeeceeseeeeecesaeseeesetasieeetetasaeeees 111 Maximum Length Sequence MLS cccccccscccsssssscscscssssscscscecececececececeseeeceseseeeeeeeeeereeernsnes 111 Octave Band Resolution vanities ceeded 112 Pink and White Noise c ccccseesccesesseeseeseeeeeceeaeseesecaeseseeecaeseeeeecaeseaeeesesasieeesesaseeesetasaeaeies 112 Schroeder Reverse Time Integration c ccccccssssessessssssssssesssssscssssscssscereseseserasarasananananes 113 Speech Transmission Index STI RSTI EXSTI cccccscecsssessssssssesssssessessessetseesessssesesessseees 113 Sampling Rate iia A 113 TOS UNC ia 114 Glossary of Audio and Acoustics Terms csceccseeseecessseeeeeeeeeeesaeeaeaeeaeaeeaeeeeaeeeeeeenees 115 Selected Bibliography ccccccsscsceccsssesseeesesesceeesesesceeeesaeaeseeesaeaesenesaeaeaeeenesaeaesenesaeanseses 118 Appendix A Troubleshooting cc cccscssesceneceeceeseeeeeeeeesesseeeeeeseenenenees 120 Installation ISSUCS AI ces 120 Computer Sound Hardware Issues c cccsecceseecseceeeeeceeseeeeeceeseeeeecesaeseecesaeseeesetaseeeesesasaees 121 Configuring Windows Audio Controls c ccccecessceseteesee
158. s Lovet 22 to measure delays in the SIA SmaartLive so if nae Impulse Output File you are familiar with SmaartLive you probably Tom fesse ema acoustic tocistsiatest wav il NETSESE already know how to use this feature The 7 interface is different but the measurement ooo oe e sp fasioo z J 4 procedure is identical a ESE 12 Pink Noise Generator At the top of the Dual FFT Time Constant 743 me 41 4 FFT tab are controls for the Intelligibility module s 4 4 internal pink noise generator This section con Eon tains a Level selector that sets the output gain Beond pea in dB and a Generate Pink Noise button that starts Cancel and stops the signal generator Use of the internal SIA Smaart Acoustic Tools Version 4 User Guide Page 31 Chapter 2 Intelligibility Module Functions and Commands signal generator is optional as the Dual FFT recording method is stimulus independent and works with virtually any type of continuous test signal including music Impulse Output File This is where you specify the name of the wave file to be used to store the measurement results You can type the path and file name for the output wave file in the text entry field or click the Browse button and use the Open file dialog box to navigate to the desired folder and specify a file name or select an existing file to overwrite Averages This value determines the number of FFT frames the Intelligibility module will record If a value gr
159. s fast as it can to changes in the input signals This will tend to stabilize the meter reading which may be desirable given the random or pseudo random stimulus signals typically used in recording impulse response measurements Note that this increased stability comes at the cost of degrading the meter ballistics Meter LED Colors The Input Level Meters are designed to display three colors the normal LED color Light Green for the Left input and Light Blue for Right plus Yellow and Red The meter LEDs will display input levels in the normal LED color up to the amplitude threshold specified for Yellow then Yellow up to the threshold for Red and Red above that level e Yellow if above Sets the threshold amplitude at which the LEDs change to Yellow e Red if above Sets the threshold amplitude above which the LED color changes to Red Numeric Readout The numeric value that appears above the Input Meters in the Record Impulse response can be set to track either the current signal level Show Current Value or the peak value Show Peak by selecting the appropriate radio button in this section Note that the Show Peak option for the numeric readout may be used with or without the Hold Peak option see above enabled for the meters themselves SIA Smaart Acoustic Tools Version 4 User Guide Page 51 Chapter 2 Intelligibility Module Functions and Commands Printing Options Menu gt Printing The Printin
160. s to the program defaults Page 96 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 3 Analysis Module Functions and Commands e Gray Plots the Spectrograph using shades of gray rather than colors This option is useful for monochrome displays or for printing purposes Note The Analysis module automatically generates the colors in the spectrum between the specified Min and Max colors using Hue Lightness and Saturation HLS calculations Frames The options listed in this section enable you to specify a time range for the Spec trograph display using FFT frame numbers rather than the Time Zoom commands e All Displays all the FFT frames calculated for a wave file to show the entire time range of the file e Custom Enables the two edit fields to the right allowing you to specify starting and ending FFT frame numbers for a custom time range you wish to display Frequency Y Scale e Linear Displays the frequency y axis of the Spectrograph plot on a linear scale e Log Displays the frequency axis of the Spectrograph plot on a ogarithmic scale Note Calibration for all frequency based display modes in the Analysis module i e all display modes except Time Display is now set from the tab of the Options dialog box SIA Smaart Acoustic Tools Version 4 User Guide Page 97 Chapter 3 Analysis Module Functions and Commands Time Display Options Menu gt Time Display The Time Display tab of the
161. se refer to Analysis Module Functions beginning on page 59 Jump to Other Programs Intelligibility Clicking the ntelligibility button in any display mode will automatically close the Analysis module while opening the Intelligibility module and loading the file that was open as File 1 in the Analysis module AcousticTools Clicking the Acoustic Tools logo above the Intelligibility button will pop up a menu that allows you to jump to and pass data to other programs if there are jumps defined it wrjumps txt See Setting Up Links to Other Programs on page 26 or more information about this feature Display Modes Time Disp Time Slice a Spectro Freq Slice SS The Display Mode buttons switch the Analysis module between its four primary display modes For information about Analysis module display modes see Analysis Module Functions beginning on page 59 Mode Specific Controls The controls in the area will below the Display Mode buttons see above will vary based on the primary display mode currently selected The Transform and Options buttons are always visible along with the Rainbow and Power Spectrum buttons in Time Slice and Frequency Slice modes respectively Below these buttons you will see range and scale and or banding controls appropriate for the primary display currently selected See Analysis Module Functions beginning on page 59 for more information about Analysis module display modes Page 58 SIA Smaart Acousti
162. selections for either program select Devices from the program s Options menu and choose the appropriate Wave in and Wave out devices and the sampling resolution bits per sample for each on the Devices tab of the Options dialog box SIA Smaart Acoustic Tools Version 4 User Guide Page 5 Chapter 2 Intelligibility Module Functions and Commands Chapter 2 Intelligibility Module Functions and Commands Navigating in the Intelligibility Module m Room wavy SIA Smaart Intelligibility File View Options Help A CE MOY ote Schroeder ETC m Inteltigibitty All Bands Table Options Band Broadband im 4 v Fo Amplitude Scale Filter Set a v Amplitude dB 0 606 4 Time Seconds The Intelligibility module user interface is designed to put the functionality required for the most common impulse analysis tasks literally at your finger tips by giving you one click access to the most commonly used functions The use of pop up menus and context sensitive dialog boxes mean you may never have to open a menu to get at all but the most advanced features In many cases simply the clicking the label or readout field for an on screen control or readout will allow you to access nearly any associated parameter or option you are likely to need Advanced users will find the high level of control and flexibility one would expect in a truly professional measurement and analysis application easily accessible through
163. sform routine calculates the FFT series used for frequency domain displays beginning with the first sample in the wave file One potential problem with this is that the peak in the impulse response may fall at a point in the FFT frame where it is attenuated by the Data Window function used in the Transform routine All the data windows provided in the Analysis module attenuate the time domain data closest to the beginning and end of each FFT frame to the largest extent but leave the samples closest to the center of the frame untouched for the most part Setting the SIA Smaart Acoustic Tools Version 4 User Guide Page 85 Chapter 3 Analysis Module Functions and Commands center point for the first FFT in the transform series on the initial peak in the impulse which normally represents the arrival of direct sound ensures that the peak data is altered as little as possible by the data window in the first FFT frame Move FFT Center Left View Menu gt Cursor gt Move FFT Center Left Keyboard Command Ctrl Alt Left Arrow Moves the selected FFT center point to the left by one pixel or one data point depend ing on the display magnification If you are zoomed in on the time x axis to the extent that individual data points are more than one pixel apart the center point will move one data point to the left Move FFT Center Right View Menu gt Cursor gt Move FFT Center Right Keyboard Command Ctrl Alt Left Arrow
164. signal generator Record Input Meters Impulse Output File Specifies the name of the file to be used to store the mea surement results Use Loopback For Time Alignment Due to a limitation in Microsoft Windows the Intelligibility module cannot through software alone determine the start time of the MLS stimulus signal accurately enough to provide the delay time through the system under test reliably But since MLS is a single channel technique this limitation can be worked around by routing the signal from the unused computer audio output back to the unused input see diagram on page 18 as a time reference This check box should be checked when using an external loopback connection When recording without a loopback signal the initial peak in the impulse response will be positioned arbitrarily at 10 or 100 milliseconds depending on the MLS Length Reference Channel The input channel used to record the external loopback signal if applicable This parameter cannot be set directly When the Use Loopback For Time Alignment box is checked the Reference Channel is set automatically to the channel not used as the Measurement Channel e g setting the Measurement Channel to Left automatically sets the Reference Channel to Right SIA Smaart Acoustic Tools Version 4 User Guide Page 33 Chapter 2 Intelligibility Module Functions and Commands Measurement Channel Sets the input channel to be used to record the output of th
165. splay indicate the boundaries of the currently displayed time range In Frequency Slice mode the Waveform Display indicates the location of the currently displayed FFT frame The amplitude y axis scale of the Waveform display is specified as a percentage of the full digital amplitude scale of the wave file For example when a 16 bit file is loaded 100 represents a range of 32767 A D units The amplitude scale of the waveform display is set from the Waveform tab of the Options dialog box see page 99 The Plot Area The Plot Area is the Analysis module s main display area for data plots in all display modes Both the Waveform display see above and the Plot Area will appear blank until a wave wav file is loaded When a new file is loaded a time domain time vs energy representation of the wave file data appears in the Waveform Display and a more detailed version the Time Display is shown in the Plot Area The Analysis module requires the waveform file s time domain data to be transformed into the frequency domain using the Transform feature see page 71 before any of the SIA Smaart Acoustic Tools Version 4 User Guide Page 57 Chapter 3 Analysis Module Functions and Commands other display modes are enabled Once the wave file has been transformed and the companion frequency domain sia file created you can select any of the four primary display modes For more information about Analysis module display modes plea
166. stic Tools Version 4 User Guide Page 65 Chapter 3 Analysis Module Functions and Commands After you have made your selection the Analysis module will automatically switch to Time Display mode and plot a signal trace for each of the two files in different colors light green for File 1 and light blue for File 2 if the default Color Scheme is used When a second file is loaded it is displayed on top of File 1 in the z axis stacking order by default In other words the File 2 trace will cover the File 7 trace both in the Waveform display and on the Time Display plot in the main plot area anywhere the two traces overlap To bring the File 7 trace to the top click the Top Trace button Clicking this button again brings File 2 back to the top and so on EE When stereo wave files are loaded the Analysis module displays only one channel for each file The Channel L R selector buttons to the right of the File 1 and File 2 information fields at the top left of the Analysis module window are used to select which Channel is displayed There are separate channel selector buttons for each file so you can select either channel of either file for display independently Note that by loading the same stereo wave file as both File 1 and File 2 you can use this feature to view both channels of the file simultaneously Important Note The file displayed on top is always the object of all commands that act only on one file at a time such as the Save Wave Zo
167. telligibility module s second ary graph windows For more information about these controls please refer to the following topics e Intelligibility Graph page 36 e All Bands Table page 38 e All Options page 47 e Amplitude Scale Commands page 43 e Octave and 1 3 Octave Band Filters page 46 e About Intelligibility Module Filters page 25 e Calculating Intelligibility from an Impulse Response page 10 SIA Smaart Acoustic Tools Version 4 User Guide Page 9 Intelligibility Module Functions Calculating Intelligibility from an Impulse Response room var Pes ro wor 0 AE When a wave file is opened or a new file is recorded in the Intelligibility module the file s raw time domain audio data is displayed in the plot area with amplitude on the y axis and time on the x axis The file name number of samples in the file and its sampling rate and resolution 8 24 bits sample are displayed in the file name and information fields at the top of the Intelligibility module window If a stereo file is loaded only one channel is displayed You can switch between channels using the L and A left right channel selector buttons to the right of the file name and information fields Band Broadband E v You can select whether to display either the unfiltered broadband data or a 1 or 1 3 octave passband using the Band spinner list to the right of the plot The available 1 or 1 3 octave bands in this list will depend on the curren
168. ternal Signal Generator 20 MLS Measurement Setup 18 Pink Noise 113 File 2 Move Left 84 Move Left Fast 84 Move Right 84 Move Right Fast 84 Reset to No Shift 84 File 2 On Top 84 File Info 69 File Menu All Bands Table 38 Create Impulse From File 34 Open 29 Print 39 Print Preview 40 74 Print Setup 40 74 Save As 29 Set All Values to Default 39 Filters 25 46 About 25 Finding Time and Amplitude Differences 24 Frames 97 Frequency Y Scale 97 Frequency Masking 102 Frequency Resolution 109 Frequency Slice 62 77 95 Power Spectrum 93 94 Frequency Zooms 91 G Getting Started 1 System Hardware 1 About Sound Hardware 1 Minimum Configuration 1 Recommended Configuration 1 Glossary of Terms 115 Graph Options 49 Impulse Output File 32 33 Impulse Response 15 17 20 34 110 Calculating Intelligibility from 10 Create From File 34 Input Levels 50 Installation 4 Intelligibility 10 13 38 All Bands Table 38 Calculating from an Impulse Response 10 Graph 13 Intelligibility Jump to 70 Intelligibility Graph 13 36 38 39 Intelligibility Graph Command 36 38 39 Intelligibility Module Commands See Intelligibility Module Commands Intelligibility Module Commands 29 File Menu Intelligibility Module 29 All Bands Table 38 Create Impulse From File 34 36 38 39 Intelligibility Graph 36 38 39 Print 39 Print Preview 39 40 73 74 Print Setup 39 40 73 74 Record Impulse 30 Save As 29 30 31 34 36 38 39 Set All Values t
169. the Frame Range readout to the right of the plot and entering a range of FFT frames in the pop up dialog The time range over which the Power Spectrum is calculated can also be specified using time coordinates or FFT frame numbers on the Power Spectrum tab of the Options dialog box SIA Smaart Acoustic Tools Version 4 User Guide Page 63 Chapter 3 Analysis Module Functions and Commands The Spectrograph Spectro i e Room way er OS 00 60 ES Fme The Spectrograph is a topo CS oe graphic representation of s 3 dimensional data with time is a ele along the x axis frequency EA g 0 208 along the y axis and ampli tude represented by color This display is similar in concept to the so called waterfall display however we feel the Spectrograph display is much easier to read and interpret than a waterfall plot once you become accustomed to it Frequency Banding a z Zoom pann 236 colors A E cor By default the all frequency based displays in the Analysis module regard the highest magnitude value actually encountered in the wave file as O dB The magnitude value for every other frequency data point is calculated relative to this O dB point Selecting Full Scale on the Calibration tab of the Options dialog box re scales the Spectrograph to regard the maximum magnitude obtainable given the wave file s sampling resolu tion as 0 dB The Full Scale and Custom calibration
170. the demo during installation If you want to install the full version to a different drive or directory you should uninstall the demo version using the Windows Add Remove Software control panel prior to installing the full version When you have made your selections the installer will create the specified program directory copy the program and support files into it register the programs and create shortcuts in the Programs submenu in the Windows Start menu and optionally the Windows desktop When the installation is complete click the Finish button to exit the installer That s it If you were asked to restart your computer after installation was completed you should do so before attempting to use either of the two Acoustic Tools program modules Otherwise you can use the software immediately Just press the Start button on the Windows Taskbar click on Programs in the menu then click on the listing for S A Smaart Acoustic Tools and select either S 4 Smaart Acoustic Tools Intelligibility or SIA Smaart Acoustic Tools Analysis f you experience any problems during or after installation refer to Appendix A of this manual beginning on page 120 for troubleshooting and technical support information Note If you have more than one sound device installed on your system the SIA Smaart Intelligibility and Analysis modules will initially select the Windows default audio input and output Wave in and Wave out devices To change the default device
171. the letter R after the number The STI and RSTI calculations require fairly significant processing time so they are calculated only upon request when you click the Calculate STI and RSTI button Once calculated these values will not change for a given file Their values are not dependent upon the level markers or the Band broadband or passband currently selected for display Other Quantitative Acoustical Values The lower section of the Intelligibility dialog box is devoted to display fields for some additional acoustical values and controls for the Clarity scale and display passband RT60 RT60 or reverberation time is an expression of the reverberant decay rate of the system under test By convention reverberation time is expressed as the amount of time it would take the system to decay 60 dB at the given rate of decay RT60 The decay rate is determined from the relative positions of the Lr and Ln markers on the plot in the main program window The value shown in this field applies only to the Band broadband or passband currently selected for display Early Decay Time This is an expression of the rate at which the system under test completes earliest stage of its decay This value is dependent on the relationship between the Ld and Lr markers on the main plot and applies only to the Band pass band currently selected for display As with RT60 the early decay time is expressed as the amount of time in seconds that wou
172. the positive or negative direction The term amplitude typically refers to numbers that are not complex or plotted on a logarithmic scale such as the numbers stored in the A D process Attenuation A decrease in the level of a signal Attenuation can refer to reduction in level for a specified frequency range or a decrease in the overall level Clarity The acoustical quantity of Clarity is defined as the ratio of the early sound to late sound The division between early and late sound is given in milliseconds and expressed as Cn where n is a value in milliseconds e g C10 C20 C50 etc Coherence A mathematical function which represents the linearity between two signals The coherence is dependent on both signals and the number of averages taken The coherence value is calculated in the frequency domain and yields a value between 0 and 1 for each frequency Compressors Electronic devices that cause changes in gain typically attenuation as a function of the input level These devices should NOT be used when making transfer function or impulse response measurements Crosstalk Undesired energy in one signal or channel appearing from an adjacent signal or channel Data Window A mathematical function used to smooth the negative effects of truncation that occurs when a finite number of FFT points are used to transform time domain data into the frequency domain The Data Window s reduce the amplitude of the time domain data at the ends
173. the signal may be too fast for the Input Level Meters to detect We recom mend keeping the overall input signal levels at about 12 dB for random noise and MLS stimulus signals and music Page 122 SIA Smaart Acoustic Tools Version 4 User Guide Appendix A Troubleshooting The Input Level Meters in the Intelligibility module Record Impulse dialog box and in the Analysis module Record Wave File dialog indicate the input signal level at the sound hardware s A D converter A D converter input voltage ranges vary Some sound cards allow you to set A D input voltage levels using jumper settings or software Some do not It is often desirable to use a mixer microphone preamp or other external device to control input levels If your computer has both microphone and line level inputs be sure to avoid sending a line level signal to a microphone input As a rule we recommend you avoid using the microphone inputs The quality of the preamp circuitry is typically very poor Problems With the Intelligibility Module Impulse Response Recorder Poor Signal to Noise Ratio If you do not see a clear peak in a new impulse response recorded in the Intelligibility module using either the MLS or Dual FFT method and or the noise floor of the measurement is too high to see acoustical information about the room system under test it may be helpful to increase the gain of the measurement microphone and or loudspeaker s used to stimulate the room In rev
174. tion card included in each SIA Smaart Acoustic Tools software package Please keep your registration card in a safe place This information may be required for you to receive technical support and product upgrades Your install codes will also be required if the program files on your hard disk are deleted or corrupted and you need to reinstall the software for any other reason It is strongly recommended that you close all other Windows programs including any automatic anti virus and or system monitor software you have running before attempting to install this software Antivirus programs in particular are known to cause conflicts with the installer program and may prevent the software from properly registering itself with the operating system Installation problems related to other software usually manifest themselves after a seemingly successful installation when one or more of SIA Smaart program module will not open Shutting down all other running programs and repeating the installation will usually correct this If you experience problems during the installation for example if the installer program hangs or issues error messages before the installation process is completed you may have a defective or otherwise unreadable installation disk If you experience problems of this nature contact SIA technical support for troubleshooting assistance Technical support contact information is listed at the end of this chapter Page 120 SIA Sm
175. tly selected Amplitude Scale Log dB hd Both Linear and Logarithmic decibel amplitude scaling are available however Log dB amplitude scaling is normally used when performing intelligibility calculations Amplitude scaling is selected using the Amplitude Scale spinner located to the right of the plot Positioning the Level Markers In dB scaling mode three markers appear on the plot labeled Ld Level direct Lr Level reverberant and Ln Level noise The time and amplitude coordinates for these three markers are used as the basis for ALCons and Clarity calculations The standard STI and RSTI calculations are not dependent on the level marker positions Page 10 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands By default the Schroeder Inverse Integration curve is calculated and displayed above the raw time domain data of the impulse response The Schroeder trace is intended mostly as a guide to help you identify the overall trends in the impulse response The three level markers should normally be positioned on the impulse response trace itself Level marker positions for fairly Level marker positions for an impulse response a typical impulse response with a late buildup of reverberant energy The Ld marker is automatically set at the position of the highest point in amplitude value found in the time domain trace when a file is loaded This will normally repre
176. tude range can also be set using the Zoom Y In Out and Move Range Up Down commands or by using your mouse to zoom in and out The Default range is the range displayed when you open a new wave file or when you use the Zoom Out To Limits command The options available in the Amplitude Range section will depend on whether a Linear or Decibel Amplitude Scale is currently selected as the range may be set independently for each scaling mode In Decibel scaling mode the Min and Max amplitude range values are set in decibels dB When calculating decibel amplitude values the Intelligibility module regards full scale the highest possible amplitude value obtainable from the wave file as zero dB and all other values are given as dB down from 0 The method used to calculate dB values from the wave file s linear amplitude units results ina maximum possible decibel range of O to approximately 210 so the maximum displayable range for the plot is 10 dB to 220 dB In Linear amplitude scaling mode the amplitude range of the plot is set as percent ages of the maximum possible positive and negative amplitude values obtainable from the wave file The default range is normally set to 100 Speed of Sound The Intelligibility module uses the Speed of Sound setting to calculate distance equivalents for time values The speed of sound value can be specified in either feet or meters depending on which of the radio buttons is selected
177. w of the time domain time vs amplitude data in a wave file The Time Display is the only display mode that can be accessed before transforming a wave file For more information please refer to The Time Display on page 59 Time Slice View Menu gt Time Slice Time a P Keyboard Command T Time Slice mode plots magnitude vs time for a given frequency range Narrow Band Octave or 1 3 Octave You could think of this plot as a horizontal slice of the Spec trograph The Time Slice display is particularly useful for looking at impulse response data For more information please refer to The Time Slice on page 60 Frequency Slice View Menu gt Frequency Slice Freq Slice Keyboard Command F The Frequency Slice displays a magnitude vs frequency plot of a selected FFT frame slice in effect a still frame spectrum analyzer You could also think of this display as a horizontal plot of a vertical slice of the Spectrograph For more informa tion refer to The Frequency Slice on page 62 SIA Smaart Acoustic Tools Version 4 User Guide Page 77 Chapter 3 Analysis Module Functions and Commands Spectrograph View Menu gt Spectrograph Spectro rn Keyboard Command S The Spectrograph is a topographical representation of the traditional waterfall display This three dimensional plot puts time on the x axis frequency on the y axis and represents amplitude using color For more i
178. will be passed to the target program This line should always be set to N if WAVE Y SIA Smaart Acoustic Tools Version 4 User Guide Page 27 Chapter 2 Intelligibility Module Functions and Commands Making a Screen Capture Microsoft Windows has a feature built in that allows you to capture the active window as a bitmap These captured screen shots are an easy way to include Smaart data displays as illustrations in reports and other documents To make a screen shot click on the window you want to capture with your mouse to make sure it is the active window and press Alt PrtScrn also be labeled as F13 on some keyboards This copies an image of the active window to the Windows clipboard The image on the clipboard can be pasted directly into some word proces sor and spreadsheet applications others may require you to save the image as a bitmap file first and then import the file into the document To save the captured image as a bitmap using the Paint program included with Windows open the program by clicking the Start button on the Windows Taskbar and selecting Programs gt Accessories gt Paint In the Paint program select Paste from the Edit menu or press Ctrl V to bring in the image from the clipboard If you see a message saying that the image is too large and asking if you want to enlarge the bitmap click Yes Then while the pasted image is still selected open the Edit menu and select Copy To In the
179. y Module Commands beginning on page 29 File Information ie Roomwav EE KOR This section of the Intelligibility Module window provides information about the primary wave file currently loaded The Open File button calls an Open file dialog box allowing you to select a wave file to load The next field to the right displays the file name of the wave file after opening it Immediately to the right of the file name field are two fields that display the number of samples in the file and the sampling rate and resolution bits sample at which the data was recorded When a stereo wave file is loaded the L and R Channel buttons select which channel is displayed The Record Rec button opens the Intelligibility module s Impulse recorder SIA Smaart Acoustic Tools Version 4 User Guide Page 7 Chapter 2 Intelligibility Module Functions and Commands Level Marker Coordinates sofia PREMIOS fo PERS jo 0911 EET The second row of display fields at the top of the Intelligibility module window give numeric coordinates for the time and amplitude positions of Ld Lr and Ln markers see Calculating Intelligibility from an Impulse Response on page 10 The first number in each field is the time position for the corresponding marker in milliseconds followed by the amplitude value in decibels The readout for the Ld marker has an additional notation indicating the polarity P or P of the highest peak in the impulse re sponse The Ld marke
180. y the decay slope and can be helpful in determining reverberation time RT60 Schroeder Trace is a toggle command Clicking the Schroeder button shown above or selecting Schroeder Trace from the Show sub menu of the View menu displays the Schroeder trace When the Schroeder is present clicking the same button or select ing the same menu command again will remove the trace from the plot SIA Smaart Acoustic Tools Version 4 User Guide Page 43 Chapter 2 Intelligibility Module Functions and Commands Schroeder On Top View Menu gt Show gt Schroeder On Top Keyboard Command Ctrl H When the Schroeder trace is displayed on the Intelligibility module plot selecting Schroeder On Top from the Show sub menu of the View menu moves the Schroeder trace to the top of the plot s z axis stacking order The z order of the plot is of concern in this case mainly because the precision tracking cursor always tracks the top trace when Track Nearest Data Point is turned on Schroeder On Top is a toggle command Selecting the same menu command again will return the impulse response trace to the top of the z order ETC View Menu gt Show gt ETC ETC a Keyboard Command Ctrl E This command calculates and displays the Energy Time Curve ETC based on the broadband or band limited time domain impulse response data When ETC is selected the ETC plot replaces the normal impulse response plot in the Plot Area
181. you to enter a text Comment to be included in the output file The Close button closes the All Bands Table dialog box Page 38 SIA Smaart Acoustic Tools Version 4 User Guide Chapter 2 Intelligibility Module Functions and Commands Set All Values to Default File Menu gt Set All Values to Default The user definable options for the Intelligibility module are very flexible and can sometimes be confusing especially at first The Intelligibility module stores the state of nearly all of these options when you exit the program so if a problem does arise chances are good that it will still be there the next time you start the program Any time you wish to restore the Intelligibility module to its factory default settings select Set All Values to Default from the File menu This will reset all virtually user definable program parameters to their original default states The only exceptions are that the Color Scheme and device selections are left as set on the Colors and Devices tabs of the Options dialog box Print File Menu gt Print Keyboard Command Ctrl P The Print command first takes you to the Custom Print Information dialog box to allow you to set title text and other options for the printout before printing The Custom Print Information dialog box can be used to set all the same printing options as the Printing tab of the Options dialog box After setting title and page options click the OK button in the Custom Print
182. ysis module allows you to specify amplitude values for each individual pair L R of LEDs Meter scaling is independent of any display calibration setting All values must be given as a negative number of decibels dB where 0 dB is equal to the maximum digital output amplitude of the selected wave in device s A D section Power Spectrum Options Menu gt Power Spectrum The default Power Spectrum an average of all FFT frames calculated for a wave file is automatically computed when the wave file is transformed You can change the time range of the Power Spectrum at any time by specifying a custom range on the Power Spectrum tab of the Options dialog box The beginning and end values for a custom range of FFT frames may be specified by FFT frame number or by time coordinates The Power Spectrum is recalculated for the specified range when you click OK to exit the Options dialog box If you entered the range using time values the Analysis module will adjust the time range specified to coincide with the beginning and end of the closest FFT frames before recalculating Printing Options Menu gt Printing The Printing tab of the Options dialog box controls the appearance and content of pages printed directly from the Analysis Module The following options are user definable Header e Title 1 2 and 3 You can specify up to three lines of title text to appear in the header section at the top of Analysis Module printouts If any

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