Bowers & Wilkins CT8XO MK2 User guide
CT800 Series
CT8XO MK2
Installation and Setup Manual
1
Table of Contents
Warranty .............................................................................................. 2
Important Safety Instructions .......................................................... 3
Environmental Information ............................................................... 4
Introduction ......................................................................................... 4
Planning the Installation ................................................................... 7
Speaker Position ................................................................................ 7
Surround Speaker Dispersion Mode ............................................... 8
Mounting the Speakers ..................................................................... 9
CT8 DS - Installation Into Drywall ......................................................11
CD8 DS - Installation to Wall Surface ................................................12
Connecting the System ....................................................................14
CT8 XO Mk2 Wiring Diagram ............................................................15
The CT8 OX Mk2 Crossover/Equaliser ...........................................15
Description of Controls .....................................................................16
Equipment Required .........................................................................17
ConguringtheCT8XOtothespeaker.............................................17
ConguringtheUnittotheGainofEachPowerAmplier .................17
ConguringtheEqualisers ................................................................18
Running In and Ancillary Equipment ............................................. 22
Aftercare ............................................................................................ 22
Technical Specications ................................................................. 23
1
2
Warranty
Dear customer,
Welcome to B&W.
Thisproducthasbeendesignedandmanufacturedtothehighestquality
standards.However,ifsomethingdoesgowrongwiththisproduct,B&W
Group Ltd and its national distributors warrant free of charge labour
(exclusionmayapply)andreplacementpartsinanycountryservedbyan
ofcialB&Wdistributor.
Limited Warranty
This limited warranty is valid for a period of ve years from the date of
purchaseortwoyearsforelectronicsincludingampliedloudspeakers.
Terms and Conditions
1 Thewarrantyislimitedtotherepairoftheequipment.Neither
transportation,noranyothercosts,noranyriskforremoval,
transportationandinstallationofproductsiscoveredbythis
warranty.
2 Thiswarrantyisonlyvalidfortheoriginalowner.Itisnot
transferable.
3 Thiswarrantywillnotbeapplicableincasesotherthandefectsin
materialsand/orworkmanshipatthetimeofpurchaseandwillnot
beapplicable:
a)fordamagescausedbyincorrectinstallation,connectionor
packing,
b)fordamagescausedbyanyuseotherthancorrectuse
describedintheusermanual,negligence,modications,oruseof
partsthatarenotmadeorauthorisedbyB&W,
c)fordamagescausedbyfaultyorunsuitableancillaryequipment,
d)fordamagescausedbyaccidents,lightning,water,reheat,
war,publicdisturbancesoranyothercausebeyondthereasonable
controlofB&Wanditsappointeddistributors,
e)forproductswhoseserialnumberhasbeenaltered,deleted,
removedormadeillegible,
f)ifrepairsormodicationshavebeenexecutedbyan
unauthorisedperson.
4 Thisguaranteecomplementsanynational/regionallawobligations
ofdealersornationaldistributorsanddoesnotaffectyour
statutoryrightsasacustomer.
How to claim repairs under warranty
Shouldserviceberequired,pleasefollowthefollowingprocedure:
1 Iftheequipmentisbeingusedinthecountryofpurchase,you
shouldcontacttheB&Wauthoriseddealerfromwhomthe
equipmentwaspurchased.
2 Iftheequipmentisbeingusedoutsidethecountryofpurchase,
youshouldcontactB&Wnationaldistributorinthecountryof
residencewhowilladvisewheretheequipmentcanbeserviced.
YoucancallB&WintheUKorvisitourwebsitetogetthecontact
detailsofyourlocaldistributor.
Tovalidateyourwarranty,youwillneedtoproducethewarrantybooklet,
completed and stamped by your dealer on the date of purchase.
Alternatively, you will need the original sales invoice or other proof of
ownershipanddateofpurchase.
2
3
Important Safety Instructions
WARNINGS:
1 Readtheseinstructions.
2 Keeptheseinstructions.
3 Heed all warnings.
4 Follow all instructions.
5 Donotusethisapparatusnearwater.
6 Cleanonlywithdrycloth.
7 Donotblockanyventilationopenings.Installinaccordancewiththe
manufacturer’s instructions.
8 Donotinstallnearanyheatsourcessuchasradiators,heatregisters,
stoves,orotherapparatus(includingampliers)thatproduceheat.
9 Donotdefeatthesafetypurposeofthepolarizedorgrounding-type
plug.Apolarizedplughastwobladeswithonewiderthantheother.
Agroundingtypeplughastwobladesandathirdgroundingprong.
Thewidebladeorthethirdprongareprovidedforyoursafety.If
theprovidedplugdoesnottintoyouroutlet,consultanelectrician
forreplacementoftheobsoleteoutlet.
10 Protectthepowercordfrombeingwalkedonorpinchedparticularly
atplugs,conveniencereceptaclesandthepointwheretheyexitfrom
theapparatus.
11 Onlyuseattachments/accessoriesspeciedbythemanufacturer.
12 Useonlywiththecart,stand,tripod,bracket,ortable
speciedbythemanufacturer,orsoldwiththeapparatus.
Whenacartisused,usecautionwhenmovingthe
cart/apparatuscombinationtoavoidinjuryfromtip-over.
13 Unplugthisapparatusduringlightningstormsorwhenunusedfor
long periods of time.
14 Referallservicingtoqualiedservicepersonnel.Servicingisrequired
whentheapparatushasbeendamagedinanyway,suchaspower-
supplycordorplugisdamaged,liquidhasbeenspilledorobjects
havefallenintotheapparatus,theapparatushasbeenexposedto
rainormoisture,doesnotoperatenormally,orhasbeendropped.
15 Donotexposethisapparatustodrippingorsplashingandensure
thatnoobjectslledwithliquids,suchasvases,areplacedonthe
apparatus.
16 TocompletelydisconnectthisapparatusfromtheACMains,
disconnectthepowersupplycordplugfromtheACreceptacle.
17 Themainsplugofthepowersupplycordshallremainreadily
operable.
18 Whenreplacementpartsarerequired,besuretheservicetechnician
hasusedreplacementpartsspeciedbythemanufacturerorhave
thesamecharacteristicsastheoriginalpart.Unauthorised
substitutionsmayresultinre,electricshockorotherhazards.
19 Forcontinuedprotectionagainstrehazard,usefusesonlyofthe
correct type and rating.
20 Thisproductshouldbeoperatedonlyfromthetypeofpowersource
indicatedbythemarkingadjacenttothepowercordentry.Ifyouare
notsureofthetypeofpowersupplytoyourhome,consultyour
product dealer or local power company.
21 Do not overload wall outlets, extension cords or integral convenience
receptacles,asthiscanresultinariskofreorelectricshock.
22 Neverpushobjectsofanykindintothisproductthroughopenings,
astheymaytouchdangerousvoltagepointsorshortoutpartsthat
couldresultinareorelectricshock.Neverspillliquidofanykind
ontheproduct.Donotplaceanyobjectcontainingliquidontopof
theproduct.
Caution:
Toreducetherisk ofelectricshock,do notdismantletheapparatus and
donotexposetheapparatustorainormoisture.Nouser-serviceableparts
inside.Referservicingtoqualiedpersonnel.
Explanation of Graphical Symbols
Thelightningashwithinanequilateral triangleisintendedto
alertyouto the presenceofuninsulated“dangerousvoltage”
within the product’s enclosure that may be of sufcient
magnitudetoconstituteanelectricshocktopersons.
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
accompanyingtheappliance.
3
4
Introduction
ThankyouforpurchasingaBowersandWilkinsCustomTheatresystem.
Sinceitsfoundationin1966,thecontinuingphilosophyofB&Whasbeen
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
appreciationofmusicandmoviestoensurethatthetechnologyisputto
maximum effect.
Custom Theatre speakers are specically designed to be built into the
fabric of the listening room or into custom furniture as part of a fully
designedtheatreconcept.Tothatend,theyincorporateseveralfeatures
thatenablethemtobeadaptedtoawiderangeofinstallationconditions
and deliver superb sound quality. However, they specically do not
incorporate features found on some other B&W products that are not
appropriatetothistypeofinstallation.Anexampleofsuchafeaturewould
betweeterontop,whichonlyoperateswellwithafree-standingspeaker.
Furthermore,becauseofthenormalcustominstallpracticeofhidingbuilt-
inspeakerswithacousticallytransparentcloththatmatchesthedécor,all
themodelsexceptonearesuppliedwithoutgrilles.Theexceptionisthe
CT8DSsurroundspeaker,whichneedstoprotrudeintotheroominorder
fortheside-ringdriverstooperateproperly.
Nomatterhowgoodthespeakersthemselvesmaybe,theywillnotdeliver
their full potential unless properly installed. Please read through this
manualfully.Itwillhelpyouoptimisetheperformanceofthesystem.
B&Wdistributestoover60countriesworldwideandmaintainsanetwork
of dedicated distributors who will be able to help should you have any
problemsyourdealercannotresolve.
AllB&Wproductsaredesignedtocomplywithinternationaldirectiveson
the Restriction of Hazardous Substances (RoHS) in electrical and
electronicequipmentandthedisposalofWasteElectricalandElectronic
Equipment (WEEE).
These symbols indicate compliance and that the products must be
appropriatelyrecycledorprocessedinaccordancewiththesedirectives.
Consultyourlocalwastedisposalauthorityforguidance.
4
Environmental Information
5
A3-wayspeakerintendedforfrontleftandrightchannels,
one placed in vertical orientation at each side of the
screen.
Afullrangesurroundspeakerthatmayoperateineither
2-way dipole or 3-way monopole mode.
A 3-way centre channel speaker that is acoustically
similar to the CT8 LR, but designed with a more
symmetrical drive unitlayoutso thatit maybeusedin
horizontal orientation immediately above or below the
screen.
Asubwooferthatmaybeaddedtoanyoralltheabove
threemodelstoextendtheirbassresponsewellbelow
theacceptedlowerlimitonhumanhearing.
Anactive,line-levelcrossover/equaliserthat:
a) isrequiredforeachCT8LR,CT8CCandCT8DS
andmustbeconguredtotheparticularspeaker
type.
b) providesactivelteringbetweenmidrangeand
bassdriversandbetweenbassdriversand
CT8 SW (if used).
c) controlswhetherasurround speaker operates in
dipole or monopole mode and, in dipole mode,
controlsthedirectionofthepositiveandnegative
polaritylobes.
d) provides high- and low-frequency level control,
plusthreeadjustableparametricequalisersto
adjustforspeaker/roominterferanceeffects.
5
CT8 LR
CT8 DS
CT8 CC
CT8 SW
CT8 XO Mk2
6
Althoughthespeakersaresemi-activeandrequireanactivecrossover,all
poweramplicationmustbeseparatelysourced.EachCT8LR,CT8CC
andCT8DSrequirestwochannelsofpoweramplication,orthreeifused
with a CT8 SW subwoofer. This allows the user maximum exibility in
choosingthesecomponents.
The CT8 SW subwoofer, unlike the majority of subwoofers currently
available, does not contain its own power amplier and is used in a
different manner than is usual. The original concept of home theatre
basedonvariousDolbyDigitalandDTSsystemsadvocatesveormore
mainchannels plusa single LowFrequencyEffects (LFE) channel.The
main channels contain full range signals and the LFE channel contains
specialeffectsuptoapproximately140Hz.Recognisingthatmanypeople
donotwant veormorefull-rangespeakersin oneroom,DolbyDigital
and DTS systems allow for the main channels to operate with small
speakershavingarestrictedbassextension.Thelowestfrequenciesfrom
these channels are ltered off and added to the LFE channel to be
reproducedbyasubwoofer.Theltercut-offfrequencyisnormallysetat
around 80Hz, the rationale being that sound gets progressively less
directional the lower the frequency and localisation becomes less
important.Thisistruetosomeextent,buttheearscanprocessdirectional
informationat very low frequenciesandthemorethebassof themain
channelsisextended,themorerealisticthesoundstagebecomes.Many
high-end processors offer lower lter cut-off frequencies for this very
reason.
Topreservethisdirectionalinformation,aCT8SWmaybeaddedtoeach
ofthemainchannelsasdesired,extendingthefrequencyresponsewell
below20Hz.Theminimumrecommendedcongurationistoassignone
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
spatialacousticimprovesasmoresubwoofersareaddedtotheremaining
channels. If higher sound levels are required for larger listening
environmentsandgreaterrealism,uptotwosubwoofersmaybeaddedto
each main channel. (It should be noted here that the addition of more
subwooferstoanysinglechannelrequiresanadjustmentofthesubwoofer
outputlevelofthatchannel’sCT8XOinordertorestorethecorrecttonal
balance.)TheLFEchannelisthendistributedtoallthemainchannelsthat
have a subwoofer assigned by the simple action of conguring the
surroundprocessorasiftherewerenosubwooferpresentandspecifying
wheretheLFEsignalshouldberouted.Strictlyspeaking,thephrase“no
subwoofer”heremeans“nosubwooferdedicatedtotheLFEchannel”.
Safety Warning!
ACT800systemiscapableofproducingveryhighsound
pressurelevels.Prolongedexposuretohighsoundlevels
canleadrsttotemporaryandlaterpermanenthearing
damage.DonotexceedrecommendedLeq(equivalent
soundlevel)exposurelevels,forexample,thosespecied
inISO1999:1990.
6
7
Planning the Installation
Check the contents against Figure 1
Planning the Installation
Becauseofthebuilt-innatureoftheinstallation,theplanningstageisof
theutmostimportance.Anyneedtoadjustspeakerposition,forexample,
isamuchmoreinvolvedprocessthanwithfree-standingspeakers.Care
mustalsobetakentoconstructpropersupportforthespeakers.Itisall
tooeasytoinducethepanelsofcustomfurnituretovibrateandcolourthe
sound unless precautions are taken to prevent it.
Speaker Position
Figures2to4showtherecommendedlocationsinplanviewforthemain
speakersin5.1,6.1and7.1channelinstallations.Somedimensions are
marked~,indicatingthatthereissomelatitudeallowedeachsideofthe
gure, and some have a recommended range for optimum results.
Subwoofersshouldbeplacedclosetothemainspeakerstowhichthey
are assigned.
For successful operation of the surround speaker, CT8 DS, in dipole
mode,it isimportantthatall listenerssit within thespeaker’snullzone.
Thisisthe60°widezoneoflowdirectsoundlevelcreatedbytheopposing
polaritydriversoneachside.Youwillnoticefromgures3and4thatfor
6.1and7.1systems,thesidespeakersareshowninlinewiththecentreof
thelisteningarea.Thisissuitableregardlessofwhetherthesespeakers
areusedindipoleormonopolemode.However,for5.1systems,thetwo
surroundspeakersshouldbeplacedsomewhatbehindthelistenersfor
effective results in monopole mode, or if you wish to switch between
monopole and dipole modes for different types of programme. If you only
everintendtousethemindipolemode,thetwosurroundspeakersshould
revert to the in-line position. Please read the discussion on surround
modesinthenextsectionforaclearerunderstandingofthebenetsof
eachtype.
Forlargeraudiencesizes,amoreevencoverageofthesurroundsound
eld 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)
aboveseatedearheight.
ForcorrectoperationoftheCT8DSindipolemode,itisimportantnotto
obstruct thesideringdrivers.Thespeaker shouldbe mountedwithat
leastthefrontportioncontainingtheside-ringdriversprotrudingintothe
roomandanycustomisedcoveringshouldbeacousticallytransparent.
7
Figure 1
Figure font: Helv 45, 7pt
Figure spacing: 7 x 7 mm
Figure 2 Figure 3
Figure 4
Figure 5
~40o
~120o
~60o
Figure 7
Figure 6
Figure 1
Figure font: Helv 45, 7pt
Figure spacing: 7 x 7 mm
Figure 2 Figure 3
Figure 4
Figure 5
~40o
~120o
~60o
Figure 7
Figure 6
Figure 1
Figure font: Helv 45, 7pt
Figure spacing: 7 x 7 mm
Figure 2 Figure 3
Figure 4
Figure 5
~40o
~120o
~60o
Figure 7
Figure 6
Figure 1
Figure font: Helv 45, 7pt
Figure spacing: 7 x 7 mm
Figure 2 Figure 3
Figure 4
Figure 5
~40o
~120o
~60o
Figure 7
Figure 6
8
Surround Speaker Dispersion Mode
Surround speakers generally fall into two main types – those that one
mightdescribeas ‘normal’ speakers- so-calledmonopoles,wherethe
sound comes from a set of drive units mounted on the front of the
enclosure-andthosethatgiveamorediffusesoundeld,suchasdipoles.
Eachtypehasitsadvantages.
Mostmulti-channelmusicisrecordedwithhomeentertainmentinmind
andismonitoredusingmonopolesurroundspeakers,whateverthemulti-
channelrecordingformat.Thisenablesbetter locationofsideandrear
images,althoughtheformationofsuchimagesisneverquiteasprecise
asitisbetweenthefrontspeakers.
Mostlmsareoriginallybalancedforcinemas,wherealargenumberof
speakersspreadaroundtheauditoriumareusedtocreatethesurround
soundeld.Inthatcasetherearemoresurroundspeakersthanthereare
discretechannelsofinformationandalesspreciseimageiscreatedthat
gives an all-enveloping effect. Dipoles and similar diffuse speakers are
betteratrecreatingthistypeofsoundeldinthehome,butusingfewer
speakerstodoit.Imagepositioningwiththesetypesofspeakerisnever
as precise as it can be with monopoles. However, they do have the
advantageofmakingiteasiertobalancethesystemforalargerlistening
area.
Youmaywellreceiveconictingadvicefromdifferentsourcesonthebest
typeofsurroundspeakertouse.Thetruthisthatthereisnooneperfect
solutionforallsituationsandthenalchoiceforanygivenapplicationwill
beinuencedbypersonalpreference.
TheCT8DSis aspecialistsurroundspeakerandhasthe advantageof
offeringa choice of bothmonopoleanddipole operation.Themodeof
operation is set by a relay inside the speaker, the state of which is
controlledfromtheCT8XOcrossover/equaliserassignedtothespeaker
via a cable connecting the 3.5mm sockets on both products. If this
cable is not tted, the speaker will only operate in monopole
mode. On the CT8 XO is a switch used to select the mode. In the
monopoleposition,thisswitchmaybeoverriddenbya12Vtriggersignal
fromthesurroundprocessor.Somesurroundprocessorscanrecognise
thetypeofprogrammebeingplayedfromacodeonthediscandallow
youtoassigna12Vtriggertothiscode.Someotherprocessorsallowyou
toassigna12Vtriggertotheinputselectionandyoumay,forexample,
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
audienceandthetypeofprogrammebeingplayed.Indeed,youmayeven
change the characteristic for different types of programme and, as the
totalenergyintotheroomisthesameinbothmodes,norecalibrationof
theinstallationisnecessarywhenswitchingbetweenthem.
The two bass drivers operate in both modes. In monopole mode, they
crossovertothemidrangeandtweeterdriveunitsonthefrontfaceand
thespeakerisacousticallysimilartotheCT8LR,butwithouttheswivelling
head. In dipole mode, the bass drivers cross over to the six side-ring
drivers. Thedriveunitson opposingsidesareconnected outof phase
withoneanother,whichcreatesawedge-shapednullzone,approximately
60owide,atrightanglestothewall.Ifthelistenerssitwithinthiszone,they
becomelessawareofthelocationofthespeakersandhearmorereected
sound;hencethediffusenatureofthesoundeld.(gure5)
8
Figure 1
Figure font: Helv 45, 7pt
Figure spacing: 7 x 7 mm
Figure 2 Figure 3
Figure 4
Figure 5
~40o
~120o
~60o
Figure 7
Figure 6
9
Foroptimumperformance,itisimportantthatthespeakersarermlyand
securelymounted.Allthespeakersmaybemounteddirectlyatoorlevel,
but,asmentionedabove,itcanbebenecialtoraisethepositionofthe
surroundspeakersand,ifthescreenishigh,itmayalsobebenecialto
dothesamewiththefrontspeakers.Inthatcase,thesupportingstructure
forthespeakersshouldbesubstantial.Ifconstructedofwoodenstudding,
theframeworkshouldbearrangedtobedirectlybeneaththefeetofthe
speaker.(gure6)
Allthespeakersareequippedwithrollerglidesonthebasepanel.These
allowthespeakerstobeeasilypushedintoplaceincustomfurniture.In
ordertopositionthespeakersaccurately,wesuggestyoucreatecircular
recesses 15mm (5/8 in) diameter in the support surface to locate the
glides.
Toavoidrockingwhenthespeakersareinposition,itis
importantthattheserecessesareaccuratelypositioned
and a foot-positioning template is supplied for this
purpose.
Theshadedareaatthefrontofthetemplateistoallowclearanceforthe
movementofthebasscones.FortheCT8DS,theside-ringdriveunits
require free acoustic access into the listening room, indicated by the
shadedareaofthetemplateextendingroundthesides.TheCT8DSwill
normallyhavethefronthalfofthecabinetprotrudingclearintotheroom.
Itmay,however,bebuiltintoafalsepillar,butthismustbeacoustically
transparentatthesides,aswellasthefront,asindicatedbytheshaded
area.
Ifthespeakersaretobeinsetinafalsewall,afronttemplateisprovided
forguidanceincuttingtheaperture.Thetemplateisthesamesizeasthe
speaker,soremembertoleavesomeclearance.Theheightofthetemplate
includestherollerglides.
Ifthespeakersare to bemounted incustomfurniture,youshould also
ensurethatitissubstantiallybuiltandnotpronetoinducedvibration.It
should be braced where necessary and it may be benecial to glue
bituminous damping pads, similar to those used in motor vehicles, to
largeunsupportedpanels.Suchpadsneedtobethickeronwoodthan
metalandaminimumof6mm(1⁄4in)shouldbeused.
Ifitisdesiredtoremovetherollerglides,usetheTorx®keysuppliedwith
thespeakertoremovetheretainingscrews.
An optional, spike foot kit is also available (Part No FP22359). The kit
contains4heavy-dutyfeetthathave40mm(1.6in)ofverticaladjustment,
allowing tilt up to 8oifdesired.Thistiltisinadditiontothatofferedbythe
adjustableheadunitoftheCT8LRandCT8CC.
Thefeetarereversible,havingaspikeforcarpetsononeendandarubber
padforvulnerablesurfacesontheother.Fittingismosteasilyaccomplished
during unpacking, when the underside of the speaker is exposed.
(gure7)
9
Mounting the Speakers
Figure 1
Figure font: Helv 45, 7pt
Figure spacing: 7 x 7 mm
Figure 2 Figure 3
Figure 4
Figure 5
~40o
~120o
~60o
Figure 7
Figure 6
Figure 1
Figure font: Helv 45, 7pt
Figure spacing: 7 x 7 mm
Figure 2 Figure 3
Figure 4
Figure 5
~40o
~120o
~60o
Figure 7
Figure 6
Notethatiftheoptionalfeetaretted,orifthespeakeris
tilted,appropriateallowanceoverandabovethatallowed
forinthetemplatemustbemadewhencuttinganaperture
inthewall.
Thethreadedbossesthatholdthefeethavealargeconicalshapeonone
side of the ange. For maximum height, t the bosses with the conical
shapetowardstheoor.(gure8)Forminimumheight,havethempointing
intothespeaker.(gure9)
Screwinthefeetclosetowhereyouthinkthenaladjustmentwillbe,with
thespikesortherubberendsoutermostasappropriatetotheoorsurface.
Ifyoudonotintendtotiltthespeakers,orientthebosseswiththecones
inwardsandleavejustenoughthreadexposedtotthelockingrings.Fit,
butdonottightenthelockingrings.
Standthespeakeruprightandadjustthefeetusingthemetalbarprovided
togivetheamountoftiltrequiredandtotakeupanyrocking.(gure10)
Finally,tightenthelockingringagainsttheboss,againusingthemetalbar.
(gure11)
The tweeter drive units are tted with a protective clear plastic cover on
delivery.Thisistoavoidthedangerofdamagingthedomewheninstalling
thespeakers.Onceinstalled,theprotectioncovershouldberemovedby
simplypullingitawayfromthespeaker.
10
Figure 8
Figure font: Helv 45, 7pt
Figure spacing: 7 x 7 mm
Figure 9
Figure 10 Figure 11
SUB +
SUB -
SUB +
SUB -
Figure 15
Figure 16a Figure 16b
Figure 17
Figure 14
CT8 XO
Figure 8
Figure font: Helv 45, 7pt
Figure spacing: 7 x 7 mm
Figure 9
Figure 10 Figure 11
SUB +
SUB -
SUB +
SUB -
Figure 15
Figure 16a Figure 16b
Figure 17
Figure 14
CT8 XO
Figure 8
Figure font: Helv 45, 7pt
Figure spacing: 7 x 7 mm
Figure 9
Figure 10 Figure 11
SUB +
SUB -
SUB +
SUB -
Figure 15
Figure 16a Figure 16b
Figure 17
Figure 14
CT8 XO
Figure 8
Figure font: Helv 45, 7pt
Figure spacing: 7 x 7 mm
Figure 9
Figure 10 Figure 11
SUB +
SUB -
SUB +
SUB -
Figure 15
Figure 16a Figure 16b
Figure 17
Figure 14
CT8 XO
CT8 DS Only
Usingthefrontaspecttemplateprovided,markroundtheoutlineatthe
desiredpositionofthespeaker.Allowalittleforclearance.
If mounting the speaker at oor level, allow extra height if there is a
horizontalstudatoorlevel.
Cutouttheapertureforthespeaker
Using the front aspect template provided, mark the centre line of the
retainingbracket ontheinsidesurfaces ofthetwovertical studseither
sideofthespeakerposition.
Screwthetwoanglebrackets(A)totheinsidefaceoftheverticalstruts.
Attachthewallbracket(C)totheanglebrackets(A)usingmachinescrews
(D)andtrappingthestudplate(B)inposition.
Patchthedrywallasnecessary.
Installation into drywall only. (gure 12)
Sothatitcanbesunkintoastandarddrywalluptotheleveloftheside-
ringdrivers,theCT8DShasarelativelyshallowcabinetforitsheightand
is front heavy. To maintain stability, it is equipped with a bracket that
enablestherearofthecabinettobeanchoredeithertoawallsurfaceor
theinternalstuddingofadrywall.
Inexistingconstruction:
Use a stud nding tool to locate the position of the vertical studs and
ensurethatthespeakerispositionedbetweenthem.
Ifthespeakeristobemountedaboveoorlevel,cutintothedrywallpanel
to expose the stud frame sufciently to allow the insertion of a cross-
braceattheappropriateheighttosupportthespeaker.
Safety Warning!
Ensurethecross-braceislevelandttedstronglyenough
to take the substantial weight of the speaker. The
speaker canbesupported bythecross-brace andthe
retaining bracket alone if desired, or a more complex
support structure may be constructed, for example to
hidetheundersideofthecabinet.
11
Figure 13
Figure 12
CT8 DS Only
Installation to wall surface only. (gure 13)
Using the front aspect template provided, mark the centre line of the
retainingbracketonthewall.
Thetwoanglebrackets(gure12-A)fromthekitarenotrequired.
Offerthewallbracket(C)tothewallandmarkthescrewpositionsateach
end.
Drillandplugthewalltotakescrewsintherange5mm-6mm(No.10to
No.12)
Screwthewallbrackettothewall,trappingthestudplate(B)inposition.
12
Figure 13
Figure 12
CT8 DS Only
...continue for all cases
Connectthesignalandtriggercablestothespeakers.
Usingtheallenkeyprovided, removethealuminiumfacingplate onthe
frontofthespeaker,takingcarethatthetweeterprotectioncoverremains
in position.
Fittheguidetubes(F)intothetwothroughholes.
Offer thespeaker intoposition,ensuringthatthe guidetubes(F)locate
overthestudsofthebracket(B).
When the speaker is fully in position hard against the wall bracket,
withdrawtheguidetubes.
Using a 1/4 inch socket drive with extension and the 13mm socket
provided,tthetwoangednuts(E)ontothethreadedstudsandtighten.
Ifthesocketdrivedoesnothaveanutretainingfeature,werecommend
theuseofasmallpieceofBostik®Blu-Tack®orsimilarreusableadhesive
topreventthenutfallingoutofthedriveduringthisoperation.
Replace the facing plate on the front of the speaker and remove the
tweeter protection cover.
Ifthespeakerismountedontheoorandrecessedintoadrywallhaving
ahorizontalstudmemberontheoorsurface,theheightdifferencemay
betakenupbyttingtheoptionalspikefeetinplaceofthetwofrontroller
glides(gure14).OnlyoneSpikefootkitwillberequiredforeachpairof
CT8 DS.
13
Figure 8
Figure font: Helv 45, 7pt
Figure spacing: 7 x 7 mm
Figure 9
Figure 10 Figure 11
SUB +
SUB -
SUB +
SUB -
Figure 15
Figure 16a Figure 16b
Figure 17
Figure 14
CT8 XO
Connecting the System
The Speakers
Allthespeakersareprovidedwithacomprehensivechoiceofconnection
methods. Binding posts accommodate 6mm (1/4 in) or 8mm (5/16 in)
spades,4mmbananaplugsandbarewireendsandaNeutrik®Speakon®
socket provides a professional industry standard multiway connection
thatmakesiteasytomakeaconnectioninconnedspaces,especially
whenitissometimesdifculttoseewhatyouaredoing.
ForallmodelsexceptthesubwooferCT8SW,therearetwoinputchannels,
one for bass and one for midrange/tweeter, requiring two channels of
poweramplication.Inallcases,ensurethatthepositiveterminalofthe
speakerisconnectedtothecorrespondingpositiveoutputconnectorof
the power amplier. Failure to observe this will result in impaired tonal
balanceandimaging.Figure15showsatypicalconnectionmethodusing
bindingpostsandgure16(a&b)thewiringconventionfortheNeutrik®
Speakon®plug.
CT8 DS Only
Inadditiontotheaudiosignalconnections,theCT8DSterminalpanel
hasa3.5mmstereojacksocket(gure17)toinputtwo12Vtrigger
signalsfromitsCT8XOunit.Useastereocoaxialcableterminatedat
eachendbya3.5mmstereojackplugtoconnecttothecomplementary
outputsocket(TRIGGEROUT)attherearoftheCT8XO.
14
Figure 8
Figure font: Helv 45, 7pt
Figure spacing: 7 x 7 mm
Figure 9
Figure 10 Figure 11
SUB +
SUB -
SUB +
SUB -
Figure 15
Figure 16a Figure 16b
Figure 17
Figure 14
CT8 XO
Figure 8
Figure font: Helv 45, 7pt
Figure spacing: 7 x 7 mm
Figure 9
Figure 10 Figure 11
SUB +
SUB -
SUB +
SUB -
Figure 15
Figure 16a Figure 16b
Figure 17
Figure 14
CT8 XO
Figure 8
Figure font: Helv 45, 7pt
Figure spacing: 7 x 7 mm
Figure 9
Figure 10 Figure 11
SUB +
SUB -
SUB +
SUB -
Figure 15
Figure 16a Figure 16b
Figure 17
Figure 14
CT8 XO
TheCT8XOisdesignedfor19-inrackmounting.Ifhousedinanenclosed
structure,properventilationmustbesuppliedasstatedintheinthesafety
instructions.
TheCT8XOisconnectedbetweenthesurroundprocessorandthepower
ampliers. The CT8 XO signal input and output connections are made
throughbalancedXLRconnectors.
ThewiringconventionforXLRconnectorsis:
Pin1:Ground
Pin2:Live(+)
Pin3:Return(-)
If12Vtriggerswitchingofthedispersionmode(monopole/dipole)ofthe
CT8DSsurroundspeakersisrequired,theassigned12Vtriggeroutput
fromthesurroundprocessorisconnectedtothe12VTRIGGERIN of one
oftheCT8XOunitsassignedtoaCT8DS.TheotherCT8XOtrigger
inputsareconnecteddaisychainfashionfromtheTRIGGERLOOP
socketofonetotheTRIGGERINofthenext.TheTRIGGEROUT sockets
areconnectedtotherelevantCT8DSspeakers.TheTRIGGERINand
TRIGGERLOOPsocketsaremono3.5mmjackswiththepositive(12V)
wireconnectedtothetipoftheplug,whereastheTRIGGEROUTsocket
is a stereo3.5mmjackonboththeCT8XOandCT8DSloudspeaker.
Figure18showsthewiringdiagramofatypical5.1CT800systemhaving
twoCT8SWspeakers,oneassignedtoeachofthefrontleftandright
channels.
15
The CT8 XO Mk2 Crossover/Equaliser
Figure 18
To MF/HF of left CT8 LR
To LF of left CT8 LR
To left CT8 SW
To MF/HF of right CT8 LR
To LF of right CT8 LR
To right CT8 SW
Front left Front right
To MF/HF of left CT8 DS
To LF of left CT8 DS
Rear left
To MF/HF of right CT8 DS
To LF of right CT8 DS
Rear right
To MF/HF of CT8 CC
To LF of CT8 CC
Centre channel
To trigger of left CT8 DS To trigger of right CT8 DS
Processor
CT8 XO MK2 Rear Panel
Description of Controls
Theunitfeaturesacomprehensivesetofcontroldtotunetheperformance
ofeachspeakeraccordingtotheconditionsofuse.Theresponsemaybe
shapedbyacombinationofthreeparametricequalisers,eachhavinga
switchablerangeof+3dB,-3dBand-6dB,andlow-andhigh-frequency
contourcontrols,theeffectsofwhichareillustratedingure19.Selection
ofthesubwooferlow-passlterfrequencyalsoprovidessomeresponse
adjustment.Inaddition,levelcontrolsareprovidedtocompensateforany
differencesingainbetweenboththesubwooferandLFpowerampliers
comparedtotheMF/HFpoweramplier.
To access the front of the unit, remove the decorative face plate by
removingthePhilipsscrewsateitherend.
Refertogure20forthelayoutoftheinputsandcontrols,whichhavethe
followingfunctions:
S1 Inputswitch Toswitchbetweentestandnormal
inputs.
T1 Test input socket To connect external signal generator.
S2 Speakerselectswitch Toswitchbetweenfront,centreand
surroundchannels.
S3 Dipoleselectswitch Toselectappropriatepositivelobe
orientationforleftandrightsurround
channelsindipolemode.
C1 High-frequencycontour SelectsHFeqoptions.±4dB.See
control figure19,bottomgraph.
C2 Low-frequencycontour SelectsLFeqoptions.±6dB.See
control figure19,topgraph
S4 Subwooferselectionswitch None,oneortwo.
S5 Subwooferlterswitch Selectssubwooferlterfrequency.
40Hz,50Hz,60Hz.
S6 LF/Subwooferxedgain EnablesordisablesLFand
subwoofergainadjustment.
C3 LFGain AdjustsLFgain.
C4 Subwoofergain Adjustssubwoofergain.
S7 Parametriclter Engagesnumberofparametriclters
incircuit.None,one,twoorthree.
S8 P1Gain Selectsgainofparametriclter1.
-6dB,-3dB,+3dB.
C5 P1Q AdjustsQofparametriclter1
0.3 to 4.
C6 P1Freq Adjustsfrequencyofparametric
lter1.25Hzto500Hz.
S9 P2Gain Selectsgainofparametriclter2.
-6dB,-3dB,+3dB.
C7 P2Q AdjustsQofparametriclter2
0.3 to 4.
C8 P2Freq Adjustsfrequencyofparametric
lter2.25Hzto500Hz.
S10 P3Gain Selectsgainofparametriclter3.
-6dB,-3dB,+3dB.
C9 P3Q AdjustsQofparametriclter3
0.3 to 4.
C10 P3Freq Adjustsfrequencyofparametric
lter3.25Hzto500Hz.
16
LFContour
HF Contour
Figure 19
Figure font: Helv 45, 7pt
Figure spacing: 7 x 7 mm
Figure 20
Figure 21
+
+
+
+
S1 T1 S2
S3
C1
C2
S5
S6
S4
C3
C4
S7
S8
C5
C6
S9
C7
C8
S10
C9
C10
Figure 21
Setting the LF gain
Disconnectthespeakersfromthepowerampliers.
ConnecttheMF/HFpowerampliertotheLFoutputoftheunit.
Settheoutputleveloftheoscillatortozeroandconnectittothetestinput
socket T1. Select the test input by switching the input switch S1 to
“Test”.
Settheoscillatorfrequencyto100Hz.
EnableLFgainadjustmentbysettingswitchS6to“LF”.
ConnecttheACvoltmetertotheoutputterminalsoftheMF/HFamplier.
Raisetheoutputleveloftheoscillatoruntilthemeterreads2volts.
SubstitutetheLFpoweramplierfortheMF/HFpowerampler.Donot
altertheoutputsettingoftheoscillator.
AdjusttheLFgaincontrol(C3)untilthemeteragainreads2volts.
Setting the subwoofer gain
Disconnectthespeakersfromthepowerampliers.
ConnecttheMF/HFpowerampliertotheSubwooferoutputoftheunit.
Settheoutputleveloftheoscillatortozeroandconnectittothetestinput
socket T1. Select the test input by switching the input switch S1 to
“Test”.
Settheoscillatorfrequencyto25Hz.
EnablesubwoofergainadjustmentbysettingswitchS6to“Sub”.
ConnecttheACvoltmetertotheoutputterminalsoftheMF/HFamplier.
Raisetheoutputleveloftheoscillatoruntilthemeterreads2volts.
SubstitutetheSubpoweramplierfortheMF/HFpoweramplier.Donot
altertheoutputsettingoftheoscillator.
AdjusttheSubgaincontrol(C4)untilthemeteragainreads2volts.
17
Figure font: Helv 45, 7pt
Figure spacing: 7 x 7 mm
Figure 20
Figure 21
+
+
+
+
S1 T1 S2
S3
C1
C2
S5
S6
S4
C3
C4
S7
S8
C5
C6
S9
C7
C8
S10
C9
C10
Figure 20
Equipment Required
ACvoltmeter•
Signalgeneratorcapableofoutputtingasinewaveupto2VRMS•
Smallandmediumsizeatbladedscrewdriverstoselectthe•
switchpositionsandadjusttherotarycontrolsoftheCT8XO.
Andtoadjusttheequaliserstooptimisethein-roomresponse:
LaptopPCwithWinMLS2004(orlaterversion)softwareinstalled•
External sound card•
Measuringmicrophone•
WinMLS may be purchased directly from the software supplier, in
whichcaseitshouldbeWinMLS2004orlaterandbetolevel3license.
Itshouldalsoincludethespeciallycreated“B&WCT800”measurement
module.Earlyversionsofthesoftwaredidnotincludethismodule,but
thelatestversionmaybedownloadedfromwww.winmls.com.
However,aspecialpackagethatincludesasuitablemicrophone,USB
sound card and a cut-down version of the software that includes
everything required for tuning a CT800 system may be obtained
directlyfromB&W.Contactyourcountrydistributorfordetails.
TheseillustrationsonthefollowingpagesrefertotheB&Wversionof
thesoftware.Thestandardversionwilldifferslightly.
Conguring the CT8 XO to the speaker
SetswitchS2toselectthetypeofspeakerassignedtotheCT8XO.Ifthe
speaker assigned isasurroundspeaker, setswitchS3 to selectleft or
rightdipolesasappropriatetoeachspeaker’spositionintheroom(gure
21).ifthesurroundspeakersaretobepermenantlyinmonopolemode,
thepositionofswitchS3isimmaterial.
Set switch S4 to select the number of subwoofers connected to the
CT8 XO.
SetswitchS5toselectthesubwooferlterfrequency.SettheS5initially
to50Hz.The40Hzor60Hzoptionsmaybeselectedifappropriatewhen
netuningtheinstallation.
Congure the unit to the gain of each power amplier
During this process, the parametric equalisers should be bypassed by
settingswitchS7to“None”andtheLFandHFcontourcontrols,C1and
C2,settozero.
Congure the Equalisers
Sensiblecorrectionofthein-roomresponserequirestheabilitytomeasure
the acoustic frequency response of each speaker individually. The
measurement microphone does notneedtobeexpensiveand suitable
electret microphones are widely available. If the appropriate measuring
equipmentisnotavailable,werecommendthattheparametricltersbe
bypassedbysettingswitchS7to0.Settingofthelow-andhigh-frequency
contourcontrolsmaybeattemptedbyeartotheuser’spreference.
Correctingforroomresonancesrequiresthought,skillandpatience.Itis
notsensibletoattempttofullyequaliseresponsedips,asthismayleadto
systemoverload.Fortunately,dipsarelessobjectionablethanpeaks.For
thisreason, eachparametriclterallowsjust3dBof boost,but6dBof
cut.
It is also not advisable to make corrections to a single position
measurement.Theresponseofthespeaker/roomcombinationcandiffer
considerably throughout the room and it is all too easy to worsen the
responseinonepositionwhilstmakingitbetterinanother.Anaverageof
severalmeasurements takenatdifferent positionsthroughouttheroom
should ideally be used to ensure an overall improvement in all listener
positions.
The Method
We suggest taking measurements at each seat position and at several
pointsoutsidetheimmediatelisteningarea.Pointthemicrophonetowards
thespeakerbeingmeasured.
Theresonanceschangewithheight.Oftenseatswillbeatthesamelevel,
soputthemicrophoneatatypicalearheight.Ifthehometheatreroomis
like a minicinema withregularrows of rakedseating, measureateach
seat at the likely ear height. Do not hand hold the microphone during
measurements.Useatripodorothermeansofholdingitstill.Itisadvisable
to make the last measuring position n (the one used for subsequent
equalisedmeasurements)theprimarylisteningposition.
Procedure
To avoid errors from airbourne background noise and electrical
interference,switchoffallsourcesintheroomsuchasairconditioning,
refrigerators etc.
SelectthetestinputbyswitchingtheinputswitchS1to“Test”.
SettingswitchS7to“None”todisabletheparametricequalisersandset
theLFandHFcontourcontrols,C1andC2,settozero.
Connecttheoutputofthesoundcardtothefronttestinputsocketofthe
CT8XOandthemicrophonetotheinputofthesoundcard.
OpenWinMLS2004
Fromthemenu,selectSetup…Load… andloadthesetupcalled“B&W
CT800”fromthe“SoundSystem”folder.
Clickthebuttontoopenthe“VolumeandInputLevels”window.
18
Laptop computer settings:
Runthelaptopfromitsbatteryanddisconnectitstransformerpower
supply when taking measurements. This will prevent noise being
generated by electrical grounding mismatches between the laptop,
soundcardandCT8XO.Makesurethebatteryisfullychargedbefore
startingthemeasuringprocedure.
Open the “Sounds and Audio Devices” window in “Control Panel”.
Click on the “Sounds” tab and select the “No Sound” option in the
“SoundScheme”drop-downmenu.
Click on the “Volume” button in the “Sound Playback” section and
make sure the Microphone “Mute” box is checked to prevent
feedback.
Clickonthe“Audio”tabandthenonthe“Volume”buttoninthe“Sound
Recording”section.Setthevolumeslidertomaximumandmakesure
the“Select”boxischecked.
Figure 22
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