CT8 XO Mk2 Manual - Bowers & Wilkins
Contents
1. 13 Connecting the System The Speakers All the speakers are provided with a comprehensive choice of connection methods Binding posts accommodate 6mm 1 4 in or 8mm 6 16 in spades 4mm banana plugs and bare wire ends and a Neutrik Speakon socket provides a professional industry standard multiway connection that makes it easy to make a connection in confined spaces especially when it is sometimes difficult to see what you are doing For all models except the subwoofer CT8 SW there are two input channels one for bass and one for midrange tweeter requiring two channels of power amplification In all cases ensure that the positive terminal of the speaker is connected to the corresponding positive output connector of the power amplifier Failure to observe this will result in impaired tonal balance and imaging Figure 15 shows a typical connection method using binding posts and figure 16 a amp b the wiring convention for the Neutrik Speakon plug CT8 DS Only In addition to the audio signal connections the CT8 DS terminal panel has a 3 5mm stereo jack socket figure 17 to input two 12V trigger signals from its CT8 XO unit Use a stereo coaxial cable terminated at each end by a3 5mm stereo jack plug to connect to the complementary output socket TRIGGER OUT at the rear of the CT8 XO 14 Figure 15 CT8 XO FROM CT8 XO INPUT HF MF POWER AMP OUTPUT _ 42. i THT _ CJ SPL dB 100 1 000 10 000 Frequency Hz Figure 25 see Save in Tune EQ lt e a m 2 xl Average _resp txt mean txt File name Save as type Data columns Files tet X Cancel I Include Header I Individual vertical axis for each dataset Place the microphone at the chosen measurement position that is closest to the speaker under test where it will measure the highest sound pressure level Set the Input Ch 1 slider to maximum Set the Output slider to zero and switch on the test signal by clicking the button Increase the output level until the Input Ch 1 level meter just goes into the red zone Decrease the Input Ch 1 level until the signal peaks between the 6dB and 3dB marks Close the Volume and Input Levels window and click the button to switch off the test signal Make sure Plot Overlay is checked to show the frequency response screen and enable several responses to be viewed simultaneously Press the F7 key to bring up the Measurement Settings window In the Levels box set the sine sweep to 40cB FS full scale Perform a number of measurements in different positions by clicking the col button or pressing the F2 key Make the last measurement you take close to the centre of the listening a
3. suBout2 sus out 00000 HFF OUT ur our INPUT Figure 18 Processor 12V TRIGGER Front left MF HF power amplifier LF power amplifier Sub power amplifier gt To left CT8 SW To MF HF of left CT8 LR To LF of left CT8 LR Front right MF HF power amplifier LF power amplifier Sub power amplifier gt To MF HF of right CT8 LR To LF of right CT8 LR gt To right CT8 SW Rear left yo MF HF power amplifier OUTPUT LF power amplifier Centre channel Aas MF HF power amplifier LF power amplifier Rear right MF HF power amplifier LF power amplifier To MF HF of To LF of left CT8 DS To trigger of left CT8 DS left CT8 DS To MF HF of right CT8 DS To LF of right CT8 DS INPUT Q E Q To trigger of right CT8 DS To MF HF of CT8 CC To LF of CT8 CC 15 Description of Controls The unit features a comprehensive set of controld to tune the performance of each speaker according to the conditions of use The response may be shaped by a combination of three parametric equalisers each having a switchable range of 3dB 3dB and 6dB and low
4. Logarithmic k Type Magnitude y General frequency domain settings F Harmonicdist Separate y Settings Horizontal axis Wertical gasa Compensation of Level frequency dependent F Microphone divide B amp K 4939 grid 2327 v M Smoothing Settings m Display in plot mien I Guidelines Settings No shift or normalization X I Values as Marks decimals 1 x FixatFreq Hz 1000 Multiply Linear fia Shift aB ie Cancel Help Figure 27 x with shift dB E Active measurement settings Time window settings for Active Measurement W Use Time Data processing before computing frequency response r Fourier transform size Zeropad to lowest possible order of two Exact same as Time Window 65536 FAIN Frequency separation 0 37 Hz C Zeropad to samples Time Data plottype settings m Various Reference measurement Divide complex active measurement with reference measurement F Use unique time window for reference measurement T Invert resulting response complex T Add frequency resolution line Settings Crie Eiaa averege wmb Plot trenster function in Scope mode Scope mode Transient signal energy v TOS v Set active as ref OK Cancel Help Memory 10 I Update after new measurement Jo reese soe consen I Divide with frequency domain ref measurement Figure 28 x
5. Mute box is checked to prevent feedback Click on the Audio tab and then on the Volume button in the Sound Recording section Set the volume slider to maximum and make sure the Select box is checked Select the test input by switching the input switch S1 to Test Setting switch S7 to None to disable the parametric equalisers and set the LF and HF contour controls C1 and C2 set to zero Connect the output of the sound card to the front test input socket of the CT8 XO and the microphone to the input of the sound card Open WinMLS2004 From the menu select Setup Load and load the setup called B amp W CT800 from the Sound System folder Click the il button to open the Volume and Input Levels window Figure 22 Frequency response T pams Fo SPL dB Frequency Hz oars od ne Oupa p input Ch 1 Input Che 2 E m Be 3 amp i 4 3 12 12 45 45 48 8 24 24 30 30 36 36 4g 48 60 60 ae et Uncal Uncal dBFS Uncal dBFS fise foo meo pn ee Figure 23 Frequency response 100 T poig 95 90 50 40 35 20 l 100 1 000 10 000 Frequency Hz Figure 24 Frequency response
6. 0 LF POWER AMP OUTPUT _ Figure 16a Figure 16b CT8 LR CC DS Figure 17 The CT8 XO Mk2 Crossover Equaliser The CT8 XO is designed for 19 in rack mounting If housed in an enclosed structure proper ventilation must be supplied as stated in the in the safety instructions The CT8 XO is connected between the surround processor and the power amplifiers The CT8 XO signal input and output connections are made through balanced XLR connectors The wiring convention for XLR connectors is Pin 1 Ground Pin 2 Live Pin 3 Return CT8 XO MK2 Rear Panel If 12V trigger switching of the dispersion mode monopole dipole of the CT8 DS surround speakers is required the assigned 12V trigger output from the surround processor is connected to the 12V TRIGGER IN of one of the CT8 XO units assigned to a CT8 DS The other CT8 XO trigger inputs are connected daisy chain fashion from the TRIGGER LOOP socket of one to the TRIGGER IN of the next The TRIGGER OUT sockets are connected to the relevant CT8 DS speakers The TRIGGER IN and TRIGGER LOOP sockets are mono 3 5mm jacks with the positive 12V wire connected to the tip of the plug whereas the TRIGGER OUT socket is a stereo 3 5mm jack on both the CT8 XO and CT8 DS loudspeaker Figure 18 shows the wiring diagram of a typical 5 1 CT800 system having two CT8 SW speakers one assigned to each of the front left and right channels TRIGGER a Loop our
7. is required when the apparatus has been damaged in any way such as power supply cord or plug is damaged liquid has been spilled or objects have fallen into the apparatus the apparatus has been exposed to rain or moisture does not operate normally or has been dropped Do not expose this apparatus to dripping or splashing and ensure that no objects filled with liquids such as vases are placed on the apparatus To completely disconnect this apparatus from the AC Mains disconnect the power supply cord plug from the AC receptacle The mains plug of the power supply cord shall remain readily operable 18 When replacement parts are required be sure the service technician has used replacement parts specified by the manufacturer or have the same characteristics as the original part Unauthorised substitutions may result in fire electric shock or other hazards 19 For continued protection against fire hazard use fuses only of the correct type and rating 20 This product should be operated only from the type of power source indicated by the marking adjacent to the power cord entry If you are not sure of the type of power supply to your home consult your product dealer or local power company 21 Do not overload wall outlets extension cords or integral convenience receptacles as this can result in a risk of fire or electric shock 22 Never push objects of any kind into this product through openings as they may touch dangerou
8. speaker should be mounted with at least the front portion containing the side firing drivers protruding into the room and any customised covering should be acoustically transparent Surround Speaker Dispersion Mode Surround speakers generally fall into two main types those that one might describe as normal speakers so called monopoles where the sound comes from a set of drive units mounted on the front of the enclosure and those that give a more diffuse sound field such as dipoles Each type has its advantages Most multi channel music is recorded with home entertainment in mind and is monitored using monopole surround speakers whatever the multi channel recording format This enables better location of side and rear images although the formation of such images is never quite as precise as it is between the front speakers Most films are originally balanced for cinemas where a large number of speakers spread around the auditorium are used to create the surround sound field In that case there are more surround speakers than there are discrete channels of information and a less precise image is created that gives an all enveloping effect Dipoles and similar diffuse speakers are better at recreating this type of sound field in the home but using fewer speakers to do it Image positioning with these types of speaker is never as precise as it can be with monopoles However they do have the advantage of making it easier t
9. three adjustable parametric equalisers to adjust for soeaker room interferance effects Although the speakers are semi active and require an active crossover all power amplification must be separately sourced Each CT8 LR CT8 CC and CT8 DS requires two channels of power amplification or three if used with a CT8 SW subwoofer This allows the user maximum flexibility in choosing these components The CT8 SW subwoofer unlike the majority of subwoofers currently available does not contain its own power amplifier and is used in a different manner than is usual The original concept of home theatre based on various Dolby Digital and DTS systems advocates five or more main channels plus a single Low Frequency Effects LFE channel The main channels contain full range signals and the LFE channel contains special effects up to approximately 140Hz Recognising that many people do not want five or more full range speakers in one room Dolby Digital and DTS systems allow for the main channels to operate with small speakers having a restricted bass extension The lowest frequencies from these channels are filtered off and added to the LFE channel to be reproduced by a subwoofer The filter cut off frequency is normally set at around 80Hz the rationale being that sound gets progressively less directional the lower the frequency and localisation becomes less important This is true to some extent but the ears can process directional information at ve
10. 483mm 19 in Depth 155mm 6 1 in 3kg 6 6 Ib Front panel Anodised Aluminium Chassis Black 25 Bowers amp Wilkins B amp W Group Ltd Dale Road Worthing West Sussex BN11 2BH England T 44 0 1903 221 800 F 44 0 1903 221 801 info bwgroup com www bowers wilkins com UK Group UK Sales T 44 1903 221 500 E uksales bwgroup com B amp W Group North America T 1 978 664 2870 E marketing bwgroupusa com B amp W Group Asia Ltd T 852 2 869 9916 E showroom bwgroup hk Copyright B amp W Group Ltd E amp OE Kevlar is a registered trademark of DuPont Rohacell is a registered trademark of R hm GmbH Printed in Canada Issue 5
11. 9 300Hz and 4kHz monopole mode 800Hz dipole mode 500W 1000W into 8Q on unclipped programme 0 192 Height 1100mm 48 3 in without spike feet Width 325mm 12 8 in Depth 250mm 9 85 in 75kg 165 Ib Cabinet Black CT8 SW Closed box subwoofer 1x 380mm 15 in carbon fibre Rohacell sandwich cone bass 6dB at 13Hz and 40kHz 18Hz 35kHz 3dB on reference axis Within 2cB of reference response Horizontal over 90 arc Vertical over 90 arc 90qB spl 2 83V 1m mf hf 2nd and 8rd harmonics 90dB 1m lt 1 30Hz 500Hz lt 0 5 45Hz 300Hz 8Q minimum 49 40Hz 500W 1000W into 8Q on unclipped programme 0 1Q Height 475mm 18 7 in without spike feet Width 475mm 18 7 in Depth 475mm 18 7 in 35kg 77 Ib Cabinet Black Model Description Functions Inputs Outputs Rated power consumption Dimensions Weight Finish CT8 XO Mk 2 mowe Bow CT800 system active bass management controller Bass midrange crossover Subwoofer bass crossover Low frequency roll off alignment High frequency roll off alignment 3 parametric equalisers Subwoofer in out Level adjustment for number of subwoofers 12V trigger switching for surround mode Line In XLR 12V trigger 8 5mm jack MF HF Line Out XLR LF Line Out XLR Subwoofer Line Out 2 x XLR 12V trigger 8 5mm jack 20W Height 44 5mm 1 75 in 1U Width
12. Bowers amp Wilkins CT800 Series CT8XO MK2 Installation and Setup Manual Table of Contents Warranty sceccceeeecceseeceeneeeeeeeeeeeeeaneeseeaeeesseaeeeseneeeeseeaeesenaeeesseaeeeseeeeeesseas 2 Important Safety Instructions ccsseeeeeseeeeeeeeeeesseeeeesseeeeeseneneees 3 Environmental Information cccsseccesseeeeeeseeeeeeeeeeesseeeeenseeseeeseeeeees 4 IMtrOGUCTION seccceeseeeeeenneesseneeeeseneeeseneeeesseaeenseneeeeseeaeessnaesenseasensenaneens 4 Planning the Installation ccccsssssessteesseesseeeseeeesseesseeeseeenseeesneees 7 Speake POSON G asnasan ea n E SES A 7 Surround Speaker Dispersion Mode cssssecesseeeeeseeeeeesseeeeeeeees 8 Mounting the Speakers ccccsecesssssessteesseesenesseeesseeseeessnenseaeseneees 9 CT8 DS Installation Into Drywall s ereiiiisinsiieriio sissies 11 CD8 DS Installation to Wall Surface oe cee teeteeeteeeeetteeetteeees 12 Connecting the System ccsessessesseeesseessneesseesteeseeessnenseeeseeeeene 14 GIB XO Mk Wiking Diagram sissies devisees nlesctis betwee dele iodain es 15 The CT8 OX Mk2 Crossover Equalliser ssseccsssstessseetesseeeeseees 15 Description o Gonto S eisern E 16 EQUIPIMEMEREGUINCD ueiran e ianea enie ena e NEIE Ae Configuring the CT8 XO to the speaker eee eeeeeteeteeeetteeettteeetteeees 17 Configuring the Unit to the Gain of Each Power Amplifier ee 17 Configuring the EgualiSErS sisien esaa 18 Running In and Ancilla
13. RNINGS 10 11 12 13 14 15 16 17 Read these instructions Keep these instructions Heed all warnings Follow all instructions Do not use this apparatus near water Clean only with dry cloth Do not block any ventilation openings Install in accordance with the manufacturer s instructions Do not install near any heat sources such as radiators heat registers stoves or other apparatus including amplifiers that produce heat Do not defeat the safety purpose of the polarized or grounding type plug A polarized plug has two blades with one wider than the other A grounding type plug has two blades and a third grounding prong The wide blade or the third prong are provided for your safety If the provided plug does not fit into your outlet consult an electrician for replacement of the obsolete outlet Protect the power cord from being walked on or pinched particularly at plugs convenience receptacles and the point where they exit from the apparatus Only use attachments accessories specified by the manufacturer AN Unplug this apparatus during lightning storms or when unused for long periods of time Use only with the cart stand tripod bracket or table specified by the manufacturer or sold with the apparatus When a cart is used use caution when moving the cart apparatus combination to avoid injury from tip over Refer all servicing to qualified service personnel Servicing
14. al to glue bituminous damping pads similar to those used in motor vehicles to large unsupported panels Such pads need to be thicker on wood than metal and a minimum of 6mm 1 4 in should be used If it is desired to remove the roller glides use the Torx key supplied with the speaker to remove the retaining screws An optional spike foot kit is also available Part No FP22359 The kit contains 4 heavy duty feet that have 40mm 1 6 in of vertical adjustment allowing tilt up to 8 if desired This tilt is in addition to that offered by the adjustable head unit of the CT8 LR and CT8 CC The feet are reversible having a spike for carpets on one end and a rubber pad for vulnerable surfaces on the other Fitting is most easily accomplished during unpacking when the underside of the speaker is exposed figure 7 Note that if the optional feet are fitted or if the speaker is tilted appropriate allowance over and above that allowed for in the template must be made when cutting an aperture in the wall The threaded bosses that hold the feet have a large conical shape on one side of the flange For maximum height fit the bosses with the conical shape towards the floor figure 8 For minimum height have them pointing into the speaker figure 9 Screw in the feet close to where you think the final adjustment will be with the spikes or the rubber ends outermost as appropriate to the floor surface If you do not intend to tilt the
15. and high frequency contour controls the effects of which are illustrated in figure 19 Selection of the subwoofer low pass filter frequency also provides some response adjustment In addition level controls are provided to compensate for any differences in gain between both the subwoofer and LF power amplifiers compared to the MF HF power amplifier To access the front of the unit remove the decorative face plate by removing the Philips screws at either end Refer to figure 20 for the layout of the inputs and controls which have the following functions S1 Input switch To switch between test and normal inputs T1 Test input socket To connect external signal generator S2 Speaker select switch To switch between front centre and surround channels S3 Dipole select switch To select appropriate positive lobe orientation for left and right surround channels in dipole mode C1 High frequency contour Selects HF eq options 4dB See control figure 19 bottom graph C2 Low frequency contour Selects LF eq options 6dB See control figure 19 top graph S4 Subwoofer selection switch None one or two S5 Subwoofer filter switch Selects subwoofer filter frequency 40Hz 50Hz 60Hz S6 LF Subwoofer fixed gain Enables or disables LF and subwoofer gain adjustment C3 LF Gain Adjusts LF gain C4 Subwoofer gain Adjusts subwoofer gain S7 Parametric filter Engages number of parametric filters in circuit None one two or t
16. at are not made or authorised by B amp W c for damages caused by faulty or unsuitable ancillary equipment d for damages caused by accidents lightning water fire heat war public disturbances or any other cause beyond the reasonable control of B amp W and its appointed distributors e for products whose serial number has been altered deleted removed or made illegible f if repairs or modifications have been executed by an unauthorised person 4 This guarantee complements any national regional law obligations of dealers or national distributors and does not affect your statutory rights as a customer How to claim repairs under warranty Should service be required please follow the following procedure 1 If the equipment is being used in the country of purchase you should contact the B amp W authorised dealer from whom the equipment was purchased 2 If the equipment is being used outside the country of purchase you should contact B amp W national distributor in the country of residence who will advise where the equipment can be serviced You can call B amp W in the UK or visit our web site to get the contact details of your local distributor To validate your warranty you will need to produce the warranty booklet completed and stamped by your dealer on the date of purchase Alternatively you will need the original sales invoice or other proof of ownership and date of purchase Important Safety Instructions WA
17. d Wilkins Custom Theatre system Since its foundation in 1966 the continuing philosophy of B amp W has been the quest for perfect sound reproduction Inspired by the company s founder the late John Bowers this quest has entailed not only high investment in audio technology and innovation but also an abiding appreciation of music and movies to ensure that the technology is put to maximum effect Custom Theatre speakers are specifically designed to be built into the fabric of the listening room or into custom furniture as part of a fully designed theatre concept To that end they incorporate several features that enable them to be adapted to a wide range of installation conditions and deliver superb sound quality However they specifically do not incorporate features found on some other B amp W products that are not appropriate to this type of installation An example of such a feature would be tweeter on top which only operates well with a free standing speaker Furthermore because of the normal custom install practice of hiding built in speakers with acoustically transparent cloth that matches the d cor all the models except one are supplied without grilles The exception is the CT8 DS surround speaker which needs to protrude into the room in order for the side firing drivers to operate properly No matter how good the speakers themselves may be they will not deliver their full potential unless properly installed Please read through t
18. d with a normal clothes brush whilst the grille is detached from the cabinet When replacing grilles ensure that the pegs are correctly aligned with the receptacles in the cabinet before pushing into place Avoid touching the drive unit diaphragms especially the tweeter as damage may result Specifications Model Description Drive Units Frequency Range Frequency Response Dispersion Sensitivity Harmonic Distortion Nominal Impedance Crossover Frequency Recommended Amplifier Power Max Recommended Cable Impedance Dimensions Weight Finish 3 way closed box system 1x 382mm 1 in metal dome high frequency 1x 150mm 6 in woven Kevlar cone FST midrange 2x 250mm 10 in Rohacell cone bass 6dB at 23Hz and 40kHz 29Hz 24kHz 3dB on reference axis Within 2cB of reference response Horizontal over 60 arc Vertical over 10 arc 93dB spl 2 83V 1m mf hf 2nd and 8rd harmonics 90dB 1m lt 1 45Hz 20kHz lt 0 5 55hZ 20kHz 8Q minimum 4Q 300Hz 4KHz 500W 1000W into 8 on unclipped programme 0 1Q Height 1100mm 43 3 in without spike feet Width 325mm 12 8 in Depth 550mm 21 65 in 85kg 187 Ib Cabinet Black CT8 CC 8 way closed box system 1x 382mm 1 in metal dome high frequency 1x 150mm 6 in woven Kevlar cone FST midrange 2x 250mm 10 in Rohacell cone bass 6dB at 23Hz and 40kHz 29Hz 24KHz 3dB on reference a
19. e appropriate height to support the speaker Safety Warning Ensure the cross brace is level and fitted strongly enough to take the substantial weight of the speaker The speaker can be supported by the cross brace and the retaining bracket alone if desired or a more complex support structure may be constructed for example to hide the underside of the cabinet Figure 12 Using the front aspect template provided mark round the outline at the desired position of the speaker Allow a little for clearance If mounting the speaker at floor level allow extra height if there is a horizontal stud at floor level Cut out the aperture for the speaker Using the front aspect template provided mark the centre line of the retaining bracket on the inside surfaces of the two vertical studs either side of the speaker position Screw the two angle brackets A to the inside face of the vertical struts Attach the wall bracket C to the angle brackets A using machine screws D and trapping the stud plate B in position Patch the drywall as necessary 11 CT8 DS Only Installation to wall surface only figure 13 Using the front aspect template provided mark the centre line of the retaining bracket on the wall The two angle brackets figure 12 A from the kit are not required Offer the wall bracket C to the wall and mark the screw positions at each end Drill and plug the wall to take screws in t
20. e installed e External sound card e Measuring microphone WinMLS may be purchased directly from the software supplier in which case it should be WinMLS 2004 or later and be to level 3 license It should also include the specially created B amp W CT800 measurement module Early versions of the software did not include this module but the latest version may be downloaded from www winmls com However a special package that includes a suitable microphone USB sound card and a cut down version of the software that includes everything required for tuning a CT800 system may be obtained directly from B amp W Contact your country distributor for details These illustrations on the following pages refer to the B amp W version of the software The standard version will differ slightly Configuring the CT8 XO to the speaker Set switch S2 to select the type of speaker assigned to the CT8 XO If the speaker assigned is a surround speaker set switch S3 to select left or right dipoles as appropriate to each speaker s position in the room figure 21 if the surround speakers are to be permenantly in monopole mode the position of switch S3 is immaterial Set switch S4 to select the number of subwoofers connected to the CT8 XO Set switch S5 to select the subwoofer filter frequency Set the S5 initially to 50Hz The 40Hz or 60Hz options may be selected if appropriate when fine tuning the installation Configure the unit to the gain of each
21. esponse at the centre frequency of each filter is at the target level the desired smoothed level Lower the filter Q controls C5 C7 amp C9 to broaden the range of the filters until the response is as smooth as possible The controls are to some extent interactive and it may be worthwhile going round the loop of checking the control settings a second time Adjust the LF and HF contour controls C1 and C2 as appropriate Additional low frequency response adjustment may be achieved by altering the subwoofer gain C4 and filter frequency S5 Additional low mid frequency adjustment may be achieved by altering the LF gain C3 If you need to equalise another speaker you must reload the CT800 setup within WinMLS and repeat the above process 21 Running In and Ancillary Equipment Aftercare Ancillary Equipment Speakers of this ability deserve signals of the highest quality Choose your electronic equipment and interconnecting cables with care We can give guidance on what to look for when choosing ancillary equipment but cannot recommend specific items The standards of such products are improving all the time and your dealer will be able to demonstrate a variety of suitable up to date products In the specification we recommend a range of amplifier powers The higher figure is defined by the power handling capability of the speaker When calculating the power handling it is assumed that the amplifier is not run into c
22. figure 6 All the speakers are equipped with roller glides on the base panel These allow the speakers to be easily pushed into place in custom furniture In order to position the speakers accurately we suggest you create circular recesses 15mm 5 8 in diameter in the support surface to locate the glides To avoid rocking when the speakers are in position it is important that these recesses are accurately positioned and a foot positioning template is supplied for this purpose The shaded area at the front of the template is to allow clearance for the movement of the bass cones For the CT8 DS the side firing drive units require free acoustic access into the listening room indicated by the shaded area of the template extending round the sides The CT8 DS will normally have the front half of the cabinet protruding clear into the room It may however be built in to a false pillar but this must be acoustically transparent at the sides as well as the front as indicated by the shaded area If the speakers are to be inset in a false wall a front template is provided for guidance in cutting the aperture The template is the same size as the speaker so remember to leave some clearance The height of the template includes the roller glides If the speakers are to be mounted in custom furniture you should also ensure that it is substantially built and not prone to induced vibration It should be braced where necessary and it may be benefici
23. gnore these changes When we now perform another measurement with the equalisation applied Ryeg the software will calculate the quantity Rneq R Rmeq a n In our case the original measurement at position 10 is Rp Now it is time to clean up the display Make sure the following button is turned off STAT To remove the measurements we used to make the reference click the erase button 2 and select the settings shown in figure 28 this will remove all the curves in the plot and remove the measurements from memory There will now be no plots showing on the screen Make sure the i AF Overlay button is in the down state Click col or press the F2 key to re measure the response at the last position This time on the screen you will be presented with the mean response Examine this mean response and consider the optimum target to aim for A flat in room response is not desirable Studies show that a more suitable target is a response that is flat up to 100Hz and then falling uniformly by a total of 6dB by 10kHz Tune the parametric filters first before using the low and high frequency contour controls There are three filters each having adjustable centre frequency gain and Q Aim to suppress peaks first Only if there are fewer than three significant peaks should you consider filling in dips 20 Figure 26 Frequency Response Spectrum Settings a El p Axes settings m Calculation settings Hz
24. he range 5mm 6mm No 10 to No 12 Screw the wall bracket to the wall trapping the stud plate B in position Figure 13 12 CT8 DS Only continue for all cases Connect the signal and trigger cables to the speakers Using the allen key provided remove the aluminium facing plate on the front of the speaker taking care that the tweeter protection cover remains in position Fit the guide tubes F into the two through holes Offer the speaker into position ensuring that the guide tubes F locate over the studs of the bracket B When the speaker is fully in position hard against the wall bracket withdraw the guide tubes Using a 1 4 inch socket drive with extension and the 18mm socket provided fit the two flanged nuts E onto the threaded studs and tighten If the socket drive does not have a nut retaining feature we recommend the use of a small piece of Bostik Blu Tack or similar reusable adhesive to prevent the nut falling out of the drive during this operation Replace the facing plate on the front of the speaker and remove the tweeter protection cover If the speaker is mounted on the floor and recessed into a drywall having a horizontal stud member on the floor surface the height difference may be taken up by fitting the optional spike feet in place of the two front roller glides figure 14 Only one Spike foot kit will be required for each pair of CT8 DS
25. his manual fully It will help you optimise the performance of the system B amp W distributes to over 60 countries worldwide and maintains a network of dedicated distributors who will be able to help should you have any problems your dealer cannot resolve CT8 LR CT8 DS CT8 CC CT8 SW CT8 XO Mk2 A3 way speaker intended for front left and right channels one placed in vertical orientation at each side of the screen A full range surround speaker that may operate in either 2 way dipole or 3 way monopole mode A 8 way centre channel speaker that is acoustically similar to the CT8 LR but designed with a more symmetrical drive unit layout so that it may be used in horizontal orientation immediately above or below the screen A subwoofer that may be added to any or all the above three models to extend their bass response well below the accepted lower limit on human hearing An active line level crossover equaliser that a is required for each CT8 LR CT8 CC and CT8 DS and must be configured to the particular speaker type provides active filtering between midrange and bass drivers and between bass drivers and CT8 SW if used controls whether a surround speaker operates in dipole or monopole mode and in dipole mode controls the direction of the positive and negative polarity lobes provides high and low frequency level control plus
26. hree S8 P1 Gain Selects gain of parametric filter 1 6qB 3dB 3cB C5 P1Q Adjusts Q of parametric filter 1 0 3 to 4 C6 P1 Freq Adjusts frequency of parametric filter 1 25Hz to SOOHz S9 P2 Gain Selects gain of parametric filter 2 6qB 3qB 3cB C7 P2Q Adjusts Q of parametric filter 2 0 3 to 4 C8 P2 Freq Adjusts frequency of parametric filter 2 25Hz to 500Hz S10 P3 Gain Selects gain of parametric filter 3 6dB 3dB 3qB C9 P3Q Adjusts Q of parametric filter 3 0 3 to 4 C10 P3 Freq Adjusts frequency of parametric filter 3 25Hz to SOOHz 16 10000 Figure 19 LF Contour 6 ot 4 LOT moo 2 a o 4 L Ler ae LoT 10 100 1000 HF Contour 6 4 2 mame ee ed ae ee o m 2 4 6 100 1000 10000 Figure 21 B lt i D EDO S Pa gt r a m 100000 Figure 20 Bowers amp Wilkins O Equipment Required e AC voltmeter e Signal generator capable of outputting a sine wave up to 2V RMS e Small and medium size flat bladed screwdrivers to select the switch positions and adjust the rotary controls of the CT8 XO And to adjust the equalisers to optimise the in room response e Laptop PC with WinMLS 2004 or later version softwar
27. i Erase fall z curves IV Clear memory all measurements that are not plotted Cancel Help Specify the number of parametric filters required by selecting 1 2 or 3 on switch S7 The markings on the filter control dials are approximate and for guidance only Set the individual filter gain controls S8 S9 amp S10 to 6dB Set the individual filter Q controls C5 C7 amp C9 to 4 This enables the centre frequency response of the filters to be seen Set the individual filter frequency controls C6 C8 amp C10 initially to 25Hz This keeps the filters away from the frequency range of interest until they are tuned one at a time to compensate the frequency response NOTE The P1 P2 and P3 frequency controls work counter clockwise to allow for ease of setting Turn the filter frequency controls C6 C8 amp C10 to the centre frequencies of the peaks or dips to be equalizsed This is an approximate initial setting Take repeated frequency response measurements to see the effects of the adjustments you are about to make Every now and then you may wish to discard plots and this may be done by unchecking those you do not need on the plot list to the right of the screen Adjust the filter centre frequencies until the measured dips in the response line up accurately with the centres of the peaks or dips originally in the response Adjust the filter gain switches S8 S9 amp S10 so that the r
28. ing very high sound pressure levels Prolonged exposure to high sound levels can lead first to temporary and later permanent hearing damage Do not exceed recommended Leq equivalent sound level exposure levels for example those specified in ISO 1999 1990 Figure 1 v oD i 3 o g Bal 8 Qs aj x S 2 teleg amp 27 5 of e S 3 ka ia k T p g 2 Zo CT8LR e e CT8 CC e e CT8 DS e e e CT8 SW o amp CT8 XO J Figure 2 a E 120 Figure 3 Figure 4 40 Planning the Installation Check the contents against Figure 1 Planning the Installation Because of the built in nature of the installation the planning stage is of the utmost importance Any need to adjust speaker position for example is amuch more involved process than with free standing speakers Care must also be taken to construct proper support for the speakers It is all too easy to induce the panels of custom furniture to vibrate and colour the sound unless precautions are taken to prevent it Speaker Position Figures 2 to 4 show the recommended locations in plan view for the main speakers in 5 1 6 1 and 7 1 channel installations Some dimensions are marked indicating that there is some latitude allowed each side of the figure and some have a recommended range for optimu
29. ions The Method We suggest taking measurements at each seat position and at several points outside the immediate listening area Point the microphone towards the speaker being measured The resonances change with height Often seats will be at the same level so put the microphone at a typical ear height If the home theatre room is like a mini cinema with regular rows of raked seating measure at each seat at the likely ear height Do not hand hold the microphone during measurements Use a tripod or other means of holding it still It is advisable to make the last measuring position n the one used for subsequent equalised measurements the primary listening position 18 Procedure To avoid errors from airbourne background noise and electrical interference switch off all sources in the room such as air conditioning refrigerators etc Laptop computer settings Run the laptop from its battery and disconnect its transformer power supply when taking measurements This will prevent noise being generated by electrical grounding mismatches between the laptop sound card and CT8 XO Make sure the battery is fully charged before starting the measuring procedure Open the Sounds and Audio Devices window in Control Panel Click on the Sounds tab and select the No Sound option in the Sound Scheme drop down menu Click on the Volume button in the Sound Playback section and make sure the Microphone
30. ld environment the damping compounds and suspension materials will take some time to recover their correct mechanical properties The drive unit suspensions will also loosen up during the first hours of use The time taken for the speakers to achieve their intended performance will vary depending on previous storage conditions and how they are used As a guide allow up to a week for the temperature effects to stabilise and 15 hours of average use for the mechanical parts to attain their intended design characteristics However longer run in periods as long as a month have been reported and there is evidence to suggest that this has little to do with the speaker changing and more to do with the listener getting used to a new sound It is especially so with highly revealing speakers such as these where there may be a significant increase in the amount of detail portrayed compared to what the listener has previously been used to the sound may at first appear too up front and perhaps a little hard After an extended period of time the sound will seem to mellow but without losing clarity and detail 22 Aftercare The speaker cabinet surfaces and the casing of the CT8 XO usually only require dusting If you wish to use an aerosol cleaner remove any speaker grilles first by gripping round the edges and gently pulling them away from the cabinet Spray onto the cleaning cloth not directly onto the cabinet The grille fabric may be cleane
31. lipping which distorts the frequency power spectrum of the signal and that the signal is normal programme material Test tones from oscillators and the like are not applicable The lower figure is the minimum we consider necessary to achieve reasonable listening levels without audible distortion in the smaller room less than 60 ms or 2000 cu ft The higher the power you use the less likely you are to experience amplifier clipping You can often tell how good an amplifier is at driving complex speaker loads by looking at its power rating into both 42 and 8Q loads The nearer the ratio is to 2 1 the better as it indicates a good current capability In order to reduce the effect the cable has on the frequency response of the speaker to inaudible levels the impedance of the cable at all frequencies measuring both positive and negative conductors in series should be kept as low as possible and certainly below 0 1 At low frequencies the DC resistance of the cable is the dominant factor and you should choose a gauge of wire sufficient to achieve the impedance requirements over the length of cable you need to use At mid and high frequencies the inductive component of the impedance can dominate the DC resistance This and other properties influenced by the detailed construction of the cable become important Running In The performance of the speakers will change subtly during the initial listening period If they have been stored in a co
32. m results Subwoofers should be placed close to the main speakers to which they are assigned For successful operation of the surround speaker CT8 DS in dipole mode it is important that all listeners sit within the speaker s null zone This is the 60 wide zone of low direct sound level created by the opposing polarity drivers on each side You will notice from figures 3 and 4 that for 6 1 and 7 1 systems the side speakers are shown in line with the centre of the listening area This is suitable regardless of whether these speakers are used in dipole or monopole mode However for 5 1 systems the two surround speakers should be placed somewhat behind the listeners for effective results in monopole mode or if you wish to switch between monopole and dipole modes for different types of programme If you only ever intend to use them in dipole mode the two surround speakers should revert to the in line position Please read the discussion on surround modes in the next section for a clearer understanding of the benefits of each type For larger audience sizes a more even coverage of the surround sound field may be obtained if the surround speakers are elevated above ear height as in a commercial cinema In that case the speakers may be raised so that the midrange tweeter array is approximately 60cm 2 ft above seated ear height For correct operation of the CT8 DS in dipole mode it is important not to obstruct the side firing drivers The
33. o balance the system for a larger listening area You may well receive conflicting advice from different sources on the best type of surround speaker to use The truth is that there is no one perfect solution for all situations and the final choice for any given application will be influenced by personal preference The CT8 DS is a specialist surround speaker and has the advantage of offering a choice of both monopole and dipole operation The mode of operation is set by a relay inside the speaker the state of which is controlled from the CT8 XO crossover equaliser assigned to the speaker via a cable connecting the 3 5mm sockets on both products If this cable is not fitted the speaker will only operate in monopole mode On the CT8 XO is a switch used to select the mode In the monopole position this switch may be overridden by a 12V trigger signal from the surround processor Some surround processors can recognise the type of programme being played from a code on the disc and allow you to assign a 12V trigger to this code Some other processors allow you to assign a 12V trigger to the input selection and you may for example use a different disc player for audio and movies and set the trigger accordingly In both these cases you may choose whichever type of operation best suits the conditions of the listening room the size of audience and the type of programme being played Indeed you may even change the characteristic for different types of
34. power amplifier During this process the parametric equalisers should be bypassed by setting switch S7 to None and the LF and HF contour controls C1 and C2 set to zero Setting the LF gain Disconnect the speakers from the power amplifiers Connect the MF HF power amplifier to the LF output of the unit Set the output level of the oscillator to zero and connect it to the test input socket T1 Select the test input by switching the input switch S1 to Test Set the oscillator frequency to 100Hz Enable LF gain adjustment by setting switch S6 to LF Connect the AC voltmeter to the output terminals of the MF HF amplifier Raise the output level of the oscillator until the meter reads 2 volts Substitute the LF power amplfiier for the MF HF power amplfier Do not alter the output setting of the oscillator Adjust the LF gain control C3 until the meter again reads 2 volts Setting the subwoofer gain Disconnect the speakers from the power amplifiers Connect the MF HF power amplifier to the Subwoofer output of the unit Set the output level of the oscillator to zero and connect it to the test input socket T1 Select the test input by switching the input switch S1 to Test Set the oscillator frequency to 25Hz Enable subwoofer gain adjustment by setting switch S6 to Sub Connect the AC voltmeter to the output terminals of the MF HF amplifier Raise the output level of the oscillator until the mete
35. programme and as the total energy into the room is the same in both modes no recalibration of the installation is necessary when switching between them The two bass drivers operate in both modes In monopole mode they cross over to the midrange and tweeter drive units on the front face and the speaker is acoustically similar to the CT8 LR but without the swivelling head In dipole mode the bass drivers cross over to the six side firing drivers The drive units on opposing sides are connected out of phase with one another which creates a wedge shaped null zone approximately 60 wide at right angles to the wall If the listeners sit within this zone they become less aware of the location of the speakers and hear more reflected sound hence the diffuse nature of the sound field figure 5 Figure 5 Mounting the Speakers Figure 6 Figure 7 For optimum performance it is important that the speakers are firmly and securely mounted All the speakers may be mounted directly at floor level but as mentioned above it can be beneficial to raise the position of the surround speakers and if the screen is high it may also be beneficial to do the same with the front speakers In that case the supporting structure for the speakers should be substantial If constructed of wooden studding the framework should be arranged to be directly beneath the feet of the speaker
36. r reads 2 volts Substitute the Sub power amplifier for the MF HF power amplifier Do not alter the output setting of the oscillator Adjust the Sub gain control C4 until the meter again reads 2 volts 17 Configure the Equalisers Sensible correction of the in room response requires the ability to measure the acoustic frequency response of each speaker individually The measurement microphone does not need to be expensive and suitable electret microphones are widely available If the appropriate measuring equipment is not available we recommend that the parametric filters be bypassed by setting switch S7 to O Setting of the low and high frequency contour controls may be attempted by ear to the user s preference Correcting for room resonances requires thought skill and patience It is not sensible to attempt to fully equalise response dips as this may lead to system overload Fortunately dips are less objectionable than peaks For this reason each parametric filter allows just 3dB of boost but 6dB of cut It is also not advisable to make corrections to a single position measurement The response of the speaker room combination can differ considerably throughout the room and it is all too easy to worsen the response in one position whilst making it better in another An average of several measurements taken at different positions throughout the room should ideally be used to ensure an overall improvement in all listener posit
37. rea and leave the microphone exactly in that position for subsequent measurements Since Plot Overlay is checked the curves will be plotted on top of each other and when finished there will be n curves displayed In the example shown in figure 22 n 10 Click the star button to display the mean value on top of all the plotted curves The average room response is then calculated figure 23 This is the response we want to equalise Un tick all the plots except the mean response figure 24 Press CTRL E to save this mean result in the Tune EQ folder if this folder doesn t exist create it in C Program Files WinMLS2004 Set EQ Then click Save and name the file for example Average_resp txt figure 25 19 To set this curve as a multiplier press the F5 key In this dialog box select the file you just saved Average_resp and under Compensation of Level check the Tune EQ multiply box as shown figure 26 This curve is now the reference and all subsequent measurements will be multiplied by this response Click OK The graphs will change but ignore these changes We now need to set division by the measurement performed in this last position with no equalisation R Press Ctrl F and make sure this last measurement is selected as shown in figure 27 in this example 10 was the last measurement position and that is therefore set as reference Click OK The graphs will change but i
38. ry Equipment sssssusssennnnnnnennunnnnnnnennnnnnnnnne 22 Aftercare 0 seecccesceeseneeeesseeeeesnneeeeseneeessneeeenseeeeensnenenssnasenennesenseneeeseneeenaas 22 Technical Specifications cccsseecccsseeeeessneeeesseeeseneeeenseeeeeseeeeeeeae 23 Warranty Dear customer Welcome to B amp W This product has been designed and manufactured to the highest quality standards However if something does go wrong with this product B amp W Group Ltd and its national distributors warrant free of charge labour exclusion may apply and replacement parts in any country served by an official B amp W distributor Limited Warranty This limited warranty is valid for a period of five years from the date of purchase or two years for electronics including amplified loudspeakers Terms and Conditions 1 The warranty is limited to the repair of the equipment Neither transportation nor any other costs nor any risk for removal transportation and installation of products is covered by this warranty 2 This warranty is only valid for the original owner It is not transferable 3 This warranty will not be applicable in cases other than defects in materials and or workmanship at the time of purchase and will not be applicable a for damages caused by incorrect installation connection or packing b for damages caused by any use other than correct use described in the user manual negligence modifications or use of parts th
39. ry low frequencies and the more the bass of the main channels is extended the more realistic the sound stage becomes Many high end processors offer lower filter cut off frequencies for this very reason To preserve this directional information a CT8 SW may be added to each of the main channels as desired extending the frequency response well below 20Hz The minimum recommended configuration is to assign one subwoofer to each of the front left and right channels restoring some directional information to the action directly on the screen and full directional information to 2 channel audio programme The sense of spatial acoustic improves as more subwoofers are added to the remaining channels If higher sound levels are required for larger listening environments and greater realism up to two subwoofers may be added to each main channel It should be noted here that the addition of more subwoofers to any single channel requires an adjustment of the subwoofer output level of that channel s CT8 XO in order to restore the correct tonal balance The LFE channel is then distributed to all the main channels that have a subwoofer assigned by the simple action of configuring the surround processor as if there were no subwoofer present and specifying where the LFE signal should be routed Strictly speaking the phrase no subwoofer here means no subwoofer dedicated to the LFE channel Safety Warning A CT800 system is capable of produc
40. s voltage points or short out parts that could result in a fire or electric shock Never spill liquid of any kind on the product Do not place any object containing liquid on top of the product Caution To reduce the risk of electric shock do not dismantle the apparatus and do not expose the apparatus to rain or moisture No user serviceable parts inside Refer servicing to qualified personnel CAUTION RISK OF ELECTRIC SHOCK DONOTOPEN Explanation of Graphical Symbols The lightning flash within an equilateral triangle is intended to J alert you to the presence of uninsulated dangerous voltage within the product s enclosure that may be of sufficient magnitude to constitute an electric shock to persons The exclamation point within an equilateral triangle is intended to alert you to the presence of important operating and maintenance servicing instructions in the literature accompanying the appliance AN Environmental Information Introduction All B amp W products are designed to comply with international directives on the Restriction of Hazardous Substances ROHS in electrical and electronic equipment and the disposal of Waste Electrical and Electronic Equipment WEEE z These symbols indicate compliance and that the products must be appropriately recycled or processed in accordance with these directives Consult your local waste disposal authority for guidance Thank you for purchasing a Bowers an
41. speakers orient the bosses with the cones inwards and leave just enough thread exposed to fit the locking rings Fit but do not tighten the locking rings Stand the speaker upright and adjust the feet using the metal bar provided to give the amount of tilt required and to take up any rocking figure 10 Finally tighten the locking ring against the boss again using the metal bar figure 11 The tweeter drive units are fitted with a protective clear plastic cover on delivery This is to avoid the danger of damaging the dome when installing the speakers Once installed the protection cover should be removed by simply pulling it away from the speaker 10 Figure 8 mi Figure 9 d Figure 10 aL Figure 11 CT8 DS Only Installation into drywall only figure 12 So that it can be sunk into a standard drywall up to the level of the side firing drivers the CT8 DS has a relatively shallow cabinet for its height and is front heavy To maintain stability it is equipped with a bracket that enables the rear of the cabinet to be anchored either to a wall surface or the internal studding of a drywall In existing construction Use a stud finding tool to locate the position of the vertical studs and ensure that the speaker is positioned between them If the speaker is to be mounted above floor level cut into the drywall panel to expose the stud frame sufficiently to allow the insertion of a cross brace at th
42. xis Within 2B of reference response Horizontal over 60 arc Vertical over 10 arc 93dB spl 2 83V 1m mf hf 2nd and 3rd harmonics 90dB 1m lt 1 45Hz 20kHz lt 0 5 55hZ 20kHz 8Q minimum 42 300Hz 4kHz 500W 1000W into 8Q on unclipped programme 0 1Q Height 325mm 12 8 in without spike feet Width 1100mm 48 3 in Depth 550mm 21 65 in 85kg 187 Ib Cabinet Black 23 Model Description Drive Units Frequency Range Frequency Response Dispersion Sensitivity Harmonic Distortion Nominal Impedance Crossover Frequency Recommended Amplifier Power Max Recommended Cable Impedance Dimensions Weight Finish 24 3 way monopole 2 way dipole selectable closed box surround system 1x 32mm 1 in metal dome high frequency 6x 100mm 4 in midrange high frequency 1x 150mm 6 in woven Kevlar cone FST midrange 2x 250mm 10 in Rohacell cone bass 6dB at 26Hz and 40kHz monopole mode 6dB at 26Hz and 22kHz dipole mode 31Hz 22kHz 3dB on reference axis monopole mode 31Hz 18kHz 3dB power averaged over front hemisphere dipole mode Monopole mode Within 2dB of reference response Horizontal over 60 arc Vertical over 10 arc Dipole mode horizontal figure of eight Effective null zone 30 250Hz 18kHz 98dB spl 2 83V 1m mf hf 2nd and 3rd harmonics 90dB 1m lt 1 45Hz 20kHz 8Q minimum 4
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