McIntosh MQ108 User manual

MQ108
CUSTOM
ENVIRONMENTAL
EQUALIZER

MQ108
CUSTOM
ENVIRONMENTAL
EQUALIZER

IMPORTANT
SAFETY
INSTRUCTIONS
THESE
INSTRUCTIONS
ARETOPROTECT
YOUANDTHE
MclNTOSH
INSTRUMENT.
BESURETO
FAMILIARIZE
YOURSELF
WITHTHEM
Copyright1993© by
MclntoshLaboratoryInc.
1.Readallinstructions- Readthesafetyandoperatinginstructionsbeforeoperatingtheinstrument.
2.RetainInstructions- Retainthesafetyandoperatinginstructionsforfuturereference.
3.Heedwarnings- Adheretowarningsandoperatinginstructions.
4.FollowInstructions- Followalloperatinganduseinstructions.
WARNING: TO REDUCE RISK OF FIRE OR ELECTRICALSHOCK, DONOT EXPOSE THIS IN-
STRUMENTTORAINORMOISTURE.
5.PowerSources- Connectthepowersupplyonlytothetypedescribedintheoperatinginstructions
orasmarkedontheunit.
6.Power-CordProtection- Routepower-supplycordssothattheyarenotlikelytobewalkedonor
pinchedbyitemsplaceduponoragainstthem,payingparticularattentiontocordsatplugs,
conveniencereceptacles,andthepointwheretheyexitfromtheinstrument.
7.Ventilation- Locatetheinstrumentforproperventilation.Forexample,theinstrumentshouldnot
beplacedona bed,sofa,rug,orsimilarsurfacethatmayblockventilationopenings;or,placed
ina built-ininstallation,suchasa bookcaseorcabinet,thatmayimpedetheflowofairthrough
theventilationopenings.
8.Heat- Locatetheinstrumentawayfromheatsourcessuchasradiators,heatregisters,stoves,or
otherappliance(includingamplifiers)thatproduceheat.
9.WallorCabinetMounting- Mounttheinstrumentina wallorcabinetonlyasdescribedintheowner's
manual.
10.WaterandMoisture- Donotusetheinstrumentnearwater- forexample,neara bathtub,washbowl,
kitchensink,laundrytub,ina wetbasement,orneara swimmingpool,etc.
11.Cleaning- Cleantheinstrumentbydustingwitha drycloth.Cleanthepanelwitha clothmoistened
witha windowcleaner.
12.ObjectandLiquidEntry- Donotpermitobjectstofallandliquidstospillintotheinstrumentthrough
enclosureopenings.
13.NonusePeriods- UnplugthepowercordfromtheACpoweroutletwhenleftunusedfora longperiod
oftime.
14.DamageRequiringService- Servicemustbeperformedbyqualifiedservicepersonnelwhen:
A.Thepowersupplycordortheplughasbeendamaged;or
B.Objectshavefallen,orliquidhasbeenspilledintotheinstrument;or
C.Theinstrumenthasbeenexposedtorain;or
D.Theinstrumentdoesnotappeartooperatenormallyorexhibitsa markedchangeinperformance;
or
E.Theinstrumenthasbeendropped,ortheenclosuredamaged.
15.Servicing- Donotattempttoservicebeyondthatdescribedintheoperatinginstructions.Allother
serviceshouldbereferredtoqualifiedservicepersonnel.
16.GroundingorPolarization- Donotdefeattheinherentdesignfeaturesofthepolarizedplug.Non-
polarizedlinecordadaptorswilldefeatthesafetyprovidedbythepolarizedACplug.
17. CAUTION:TOPREVENTELECTRICALSHOCKDONOTUSETHIS(POLARIZED)PLUG
WITHANEXTENSIONCORD,RECEPTACLEOROTHEROUTLETUNLESSTHEBLADESCAN
BEFULLYINSERTEDTOPREVENTBLADEEXPOSURE.
ATTENTION:POURPREVENIR LES CHOCSELECTRIQUES PAS UTILISERCETTE
FICHEPOLARISEEAVECUNPROLONGATEUR,UNEPRISEDECOURANTOUUNEAUTRE
SORTIEDECOURANT,SAUFSILESLAMESPEUVENTETREINSEREESA FONDSANSEN
LAISSERAUCUNEPARTIEA DECOUVERT.
Thelightningflashwitharrowhead,withinanequilateraltriangle,isintendedtoalertthe
usertothepresenceofuninsulated"dangerousvoltage"withintheproduct'senclosure
thatmaybeofsufficientmagnitudetoconstitutea riskofelectricshocktopersons.
CAUTION:TOPREVENTTHERISKOFELECTRICSHOCK,DONOT
REMOVECOVER(ORBACK).NOUSER-SERVICABLEPARTSINSIDE.
REFERSERVICINGTOQUALIFIEDPERSONNEL.
Theexclamationpointwithinanequilateraltriangleisintendedtoalerttheusertothe
presenceofimportantoperatingandmaintenance(servicing)instructionsintheliterature
accompanyingtheappliance.
WARNING:THISUNITISCAPABLEOFPRODUCINGHIGHSOUND
PRESSURELEVELS.CONTINUEDEXPOSURETOHIGHSOUND
PRESSURELEVELSCANCAUSEPERMANENTHEARINGIMPAIRMENT
ORLOSS.USERCAUTIONISADVISEDANDEARPROTECTIONIS
RECOMMENDEDWHENPLAYINGATHIGHVOLUMES.
2

YourdecisiontoownthispieceofMclntoshStereoEquipmentranksyouattheverytop
amongdiscriminatingmusiclisteners.Younowhave"TheBest".TheMclntoshdedication
to"Quality",isassurancethatyouwillreceivethousandsofhoursofmusicalenjoymentfrom
thisunit.
Pleasetakea shorttimetoreadtheinformationinthismanual.Wewantyoutobeasfamiliar
aspossiblewithallthefeaturesandfunctionsofyournewpieceofMclntosh.Thiswillensure
thatyoureceivealltheperformancebenefitsthisinstrumentcanofferyou,andthatitwill
becomea highlyvaluedpartofyourhomemusicsystem.
SERVICECONTRACT4
INTRODUCTION5
ROOMACOUSTICS5,6
EQUALIZINGFOROPTIMUMLISTENING6,7
HOWTOCONNECT7
MEASURINGTHEROOMACOUSTICS7
HOWTOPROGRAMTHEMQ1088,9
SPECIFICATIONS10
RESPONSECURVES11,12
CHARTS13,14
THANK
YOU
TABLEOF
CONTENTS
3
Uponapplication,MclntoshLaboratoryprovidesa ServiceContracttotheoriginalpurchaser.
YourMclntoshAuthorizedServiceAgencycanexpediterepairswhenyouprovidethemwith
theServiceContract.
Theserialnumber,purchasedate,andMclntoshLaboratoryServiceContractnumberare
importanttoyouforpossibleinsuranceclaimorfutureservice.Recordthisinformationhere.
PurchaseDateSerialNumber
ServiceContractNumber

TAKEADVANTAGEOF3 YEARSOFCONTRACTSERVICE.
FILLINTHEAPPLICATIONNOW.
YourMQ108CustomEnvironmentalEqualizerwillgiveyoumanyyearsofsatisfactoryperfor-
mance.Ifyouhaveanyquestions,pleasecontact,
AnapplicationforA THREEYEARSERVICECONTRACTisincludedwiththismanual.
Thetermsofthecontractare:
1.Iftheinstrumentcoveredbythiscontractbecomesdefective,Mclntoshwillprovideallparts,
materials,andlaborneededtoreturnthemeasuredperformanceoftheinstrumenttothe
originalperformancelimitsfreeofanycharge.Theservicecontractdoesnotcoverany
shippingcoststoandfromtheauthorizedserviceagencyorthefactory.
2.AnyMclntoshauthorizedserviceagencywillrepairallMclntoshinstrumentsatnormal
servicerates.Toreceivethefreeserviceunderthetermsoftheservicecontract,theser-
vicecontractcertificatemustaccompanytheinstrumentwhentakentotheserviceagency.
3.Alwayshaveservicedonebya Mclntoshauthorizedserviceagency.Ifthe instrument is
modified or damaged as a result of unauthorized repair the service contract will be canceled.
Damagebyimproperuseormishandlingisnotcoveredbytheservicecontract.
4.Theservicecontractisissuedtoyouastheoriginalpurchaser.Toprotectyoufrom
misrepresentationthiscontractcannotbetransferredtoa secondowner.
5.UnitsinoperationoutsidetheUnitedStatesandCanadaarenotcoveredbytheMclntosh
FactoryServiceContract,irrespectiveoftheplaceofpurchase.Norareunitsacquired
outsidetheUSAandCanada,thepurchasersofwhichshouldconsultwiththeirdealer
toascertainwhat,ifany,servicecontractorwarrantymaybeavailablelocally.
4
MclNTOSH
THREEYEAR
SERVICE
CONTRACT
MclntoshLaboratoryInc.
2ChambersStreet
Binghamton,NewYork13903-2699
Phone:[phone]

TheMQ108isa programmablesevenbandequalizer.Therearetwofilterbandsforeach
channel,makinga totalof14.Eachfiltercanbeprogrammedforfrequency,bandwidthand
amplitudeboostorcut.Ithas1/3octaveselectivitycapability.TheMQ108connectstoa stereo
systembetweena preamplifierorcontrolcenterandthepoweramplifier.
TheMQ108isdesignedtocorrectforfrequencyresponseproblemscreatedbystanding
wavesandresonancesinthelisteningroom.Therequiredprogrammingisaccomplishedby
firstmeasuringthefrequencyresponseoftheloudspeakersinthelisteningroomwitha 1/3
octaveanalyzertodeterminethefrequencyrangesthatneedtobecompensated.Then
capacitorsofthepropersizetoaffecteachoftheneededfrequencyrangesandchannels
areinsertedintothesocketpinsprovidedintheMQ108.Adjustmentsarethenmadewith
thelevelcontrolforeachbandtoachievethedesiredresults.RefertothesectionHOWTO
PROGRAMTHEMQ108fordetails.
TheMQ108wasdesignedtobeusedina stereosystemtocorrectforproblemscaused
bytheroomacoustics.Althoughtheequalizerisnotdesignedtocorrectspecificloudspeaker
problemsorlimitations,itcanbehelpfulinimprovingthesoundofanyloudspeakersystem
ina typicallisteningroom.Thebestresultswillalwaysbeachievedifa loudspeakersystem
ofthehighestqualityisused.
Loudspeakerperformanceisaffectedbythelisteningroominthefollowingways.
•Thepositionoftheloudspeakersintheroom.
•Thepositionofthelistenerintheroom.
•Thedimensionsoftheroom.
•Thewall,floorandceilingcovering.
•Thestiffnessorflexibilityoftheroomsurfaces.
•Reflectionsfromfurnitureorsubstructuresintheroom.
Allthesefactorscanaffectthesoundbalance.Standingwavesorroomresonancesoccur
duetoreflectionsofthesoundfromwalltowall,fromfloortoceilingandfromanyother
roomstructures.Theacousticcharacteristicsofa typicallisteningroomcanaffectloudspeaker
performanceusuallyatfrequenciesbelow1000Hz.Themostpronouncedeffectsareatfre-
quenciesbelow250Hzandcanalterfrequencyresponseasmuch as± 15dB.
Thesefrequencyresponsevariationsarethegreatestina squareroomwithequaldimen-
sionsfromwalltowallandfloortoceiling.A highqualityloudspeakerwiththeabilitytoradiate
perfectlyuniformfrequencyresponsecanhaveitssoundcharacteristicschangeddrastically
bya roomwithseverestandingwaves.Inmosteverycasethechangewilldegradethelisten-
ing.Themostcommoneffectisoneormorepeaksinthebassfrequencyrange.Thesebass
peakstendtomaskthehighfrequencieswhichdonotnormallycreatestandingwavesdue
totheirshorterwavelengths.Therecanalsobedipsinthebassresponseatcertainfrequency
bands.Althoughdipsinbassfrequencyresponseareundesirable,theygenerallyareless
objectionablethanbasspeaks.
Amultibandequalizer,properlyprogrammed,canmakedramaticimprovementsinthesound
ofa highqualitystereosystem.Sincetheresponsepeaksanddipscanoccurovera very
narrowrangeoffrequencies,1/3octavemeasurementandcorrectiveequalizationisessential.
Bothleftandrightloudspeakersina stereosystemmustbeequalizedindependently.Since
theloudspeakersareindifferentpositionsintheroom,eachspeakerwilldrivetheroomto
5
INTRODUCTION
ROOMACOUSTICS

resonancesatdifferentfrequencies.Itisessentialforthefrequencyresponseofbothspeakers
tobesimilarifyouaretohearthefulldepthandspacepotentialofyourspeakersystems.
Aloudspeakersystemcouldbeadjustedtomeasureanacousticallyflatfrequencyresponse
acrosstheentireaudiorangeof20Hzto20,000Hz.However,thistypeofsystemalmostalways
soundstoobright.Thereareseveralreasonsforthiseffect,whichincludehumanhearing,
recordingmethods,andtheacousticsofthelivingroomandconcerthall.
Howtheearhears,differsfromtypicalmeasuringtechniquesinwaysthatcanbe
misleading.Mostmeasurementscombinetheeffectsofthedirectsoundfromtheloudspeaker
withthemultipleroomreflectionsorreverberation.Sincetypicalroomacousticsaccentuate
lownotesandattenuatehighnotes,theresponseofa goodloudspeakerwillautomatically
takeona downwardslopeina typicallisteningroomtheear,however,placesmoreemphasis
onthedirectsoundthathasarrivedunmodifiedfromtheloudspeaker.Equalizingtheoverall
sound(bothdirectandreflected)toflatwouldgivea strongly risingcharactertotheimpor-
tantdirectsoundandanoverallbrightsoundquality.
Additionally,mostrecordingsareusuallymadewiththemicrophonesrelativelycloseto
theinstruments.Thisisdonetoavoidincludingtoomuchoftheambienceoftherecording
studioorconcerthallacousticsintheoriginalrecording.However,itiscommonpractice
inrecordingclassicalmusictoplaceadditionalmicrophoneswellbackfromtheinstruments
inordertointentionallypickupa certainamountoftheconcerthallreverberation.Theout-
putsfromthese"Far"microphonesisthenblendedina preciseamountwiththeoutputfrom
the"Near"microphonestoadda desireddegreeoflivenessandrealismtotherecording.
Concert hallacousticswillmodifylivesoundandcausea gradualrolloffinhighfrequen-
cies.Thisreductionofhighfrequenciesisduetotheabsorptionandlossesinair,andin-
creasesasthedistancefromtheinstrumentsincreases.
Typicalhomelisteningroomsaremuch smallerthana concerthallandtheloudspeakers
aremuch closertothelistenerthantheinstrumentsintheconcerthall.Thesesmallerroom
dimensionsresultinmuch lesshighfrequencyattenuationfromtheloudspeakerstothe
listeners.Theeffectsofreflectedsoundarealsomorepronouncedinthesmallerlistening
room.
Whenrecordingsmadewithmostly"Near"microphonetechniquesarereproducedina
homestereosystem,theyproducea much brightersoundthanthatheardintheoriginalcon-
certhall.Thelisteningroomdoesnotfurnishthegradualhighfrequencyrolloffthatoccurs
inthelargerconcerthall.
Roomequalizationthereforeinvolveseliminationofthemostobviouspeaksanddipsin
response,aswellasa generalcontouringoftheoverallfrequencyresponse.Thecurvesin
thegraphbelowhavebeencompiledfromlisteningtests,roommeasurementsandconcert
hallmeasurements.Thesecurvesareintendedonlyasa guidetoestablishingthedesired
systemresponseinthelisteningarea.
Smoothnessintheresponsecurvecanbecorrectedbyuseofspectrumanalyzer
measurements.However,thefinalcurvecontourshouldbecarefullyconsideredbasedon
listeningevaluationandtheindividuallistenerpreferences.Thetypeofmusicthelistener
prefersusuallyisa majorfactorinselectingthedesiredcurvecontour.
Generally,a person wholistenstoclassicalmusicwillprefera responsebetweencurves
BandC.A personwholikescontemporaryorrockmusicmayprefera responsebetween
6
ROOMACOUSTICS
EQUALIZING
FOROPTIMUM
LISTENING

curvesA andB.A personwholistenstobothrockandclassicalusuallywillprefercurveB.
Smoothingtheroomresponseandfrequencycontouringcanbeaccomplishedbyproperpro-
grammingoftheMQ108equalizer.
ConnecttheMQ108betweentheoutputsofa preamplifierorcontrolcenterandtheinputs
ofa poweramplifier.TheMQ108hasbothBalancedandUnbalancedinputsandoutputs.
TheMQ108canalsobeconnectedbetweenthepreamplifieroutputsandpoweramplifier
inputsona receiverorintegratedamplifier-preamplifier.
ItisnotrecommendedthattheMQ108beconnectedtoa tapemonitorlooporsignalpro-
cessingloop,sincethehighoutputlevelscouldpossiblyoverdrivetheMQ108inputs.
BalancedJack PinConfiguration:
Pin1.SystemGround
Pin2.+ Signal
Pin3.- Signal
ACPOWER
ConnecttheMQ108ACpowercordintoa switchedACoutletona preamplifierorcontrol
center.TheMQ108willthenturnonandoffwiththerestofthesystem.
Beforeequalizationisperformed,theroomresponsemustfirstbemeasuredwitha Spec-
trumAnalyzerwiththirdoctaveresolution.AnanalyzersuchastheAudioControlSA-3050A,
MclntoshAA2orothersimilaranalyzerwillbesatisfactory.
Theanalyzermicrophoneshouldbelocatedinthelisteningareaatnormalearheight.
Measurementsshouldbemadeforeachstereochannelseparately.Theresultswillberead
ontheinstrumentdisplay,orbya meter,dependingonthetypeofanalyzerused.Youmay
finditconvenienttopencilintheresponseindicationsononeofthefrequencyresponsecharts
includedinthismanual.Thiswillbecomeyourinitialreferencefordeterminingtheneeded
equalization.
Aftertheinitialroommeasurementsaremade,andtherequiredequalizationisdetermined,
theMQ108shouldbeprogrammed.Thesameroommeasurementsmustthenberepeated
todeterminetheresultsoftheequalization.
Sincesomanyvariablesarepresentwithroomequalizationandlistenerpreferences,you
mayfinditdesirabletomeasureandthenprogramtheequalizermorethanonce,depending
ontheresultsoflisteningtestsuntilyougetthedesiredresults.A convenientIN-OUTequaliza-
tionswitchisprovidedontheMQ108forinstantcomparisonofthesystemequalizedand
unequalized. WhentheswitchifOUT,allequalizationcircuitsarebypassed.Whenthecircuit
isIN,allequalizationincludingHIGHFREQUENCYCOMPENSATIONisinthecircuitandactive.
7
EQUALIZING
FOROPTIMUM
LISTENING
HOWTO
CONNECT
MEASURING
THEROOM
ACOUSTICS

RemovetheMQ108covertoaccessalltheprogrammingfeatures.TheMclntoshMQ108
has14programmablefilterbands(sevenineachchannel).Eachfiltercanbeprogrammed
forfrequencyandbandwidth.Eachfilterisalsoadjustableforamplitudeboostorcut.The
frequency,bandwidthandamplitudeofeachprogrammedsectionisdeterminedbytheselec-
tionofcapacitorsandthepositionofthelevelcontrol.ThecapacitorsrequiredbytheMQ108
areofstandardvaluesandreadilyavailable.
Eachfiltersectionisidentifiedbynumber,whichincludesa detentedlevelcontrolandtwo
capacitorplug-inlocations,A andB.Whenthecontrolissetatthedetentedposition,the
filteriselectricallyflat.Whenthedesiredcapacitorsareinsertedandthecontrolisturned
clockwise,thefilterboosts.Whenthecontrolisturnedcounterclockwise,thefiltercuts.
CapacitorsA andB programthefrequencyandbandwidthofthefilter.Capacitorvalues
aredeterminedbyusingtheFREQUENCYPROGRAMMINGtableonthechartincludedin
thismanualandalsoattachedtotheinsideoftheMQ108cover.Ifnocapacitorsareinserted
ina filtersection,turningthecontrolwillhavenoeffect.Bothcapacitorsmustbeusedin
thesamesectionforproperoperation.
NARROWFILTERWIDEFILTER
CAPACITORCAPACITORCAPACITORCAPACITOR
FREQUENCY(Hz)A B A B
20
25
31.5
40
50
63
80
100
125
160
200
250
315
400
500
630
800
1000
1.0
1.0
1.0
.56
.56
.39
.22
.22
.18
.12
.12
.12
.082
.056
.056
.039
.022
.022
.39
.27
.18
.18
.12
.12
.12
.082
.056
.056
.039
.022
.022
.018
.012
.012
.012
.0082
4.7
2.2
1.0
.56
.056
.022
.018
.0082
Capacitorsforfrequenciesthatarenotindicatedontheenclosedchartcanbedetermined
bythefollowingformula.
8
HOWTO
PROGRAM
THEMQ108

CAPACITOR
CapacitorA
inMicrofarads
CapacitorB
inMicrofarads
NARROWFILTER
23.5
Frequency(Hz)
7.2
Frequency(Hz)
WIDEFILTER
118
Frequency(Hz)
1.44
Frequency(Hz)
Preferredcapacitorsaremetalizedpolyesterorequivalent,andshouldhavea voltagerating
of50Vorhigher.
CAPACITORINSERTIONandEQUALIZATIONADJUSTMENT
Twopairsofcapacitorconnectingpinsocketsareprovidedforeachequalizersection,
markedA andB.Itisnotnecessarytoobservethepolarityoftheelectrolyticcapacitors.
Forexample,selectthenarrowfilterat31.5Hzasthefirstbandofequalizationintheleft
channel.Inserta 1.0capacitorintothe1L,A connectingsockets.Inserta .18capacitorin
the1L,B connectingsockets.Bothcapacitorsmustbeinsertedforproperperformance.Select
andinsertcapacitorsforthenextfrequencytoprogramontheleftchannelinthe2Lconnect-
ingsockets.Thefirstfrequencytobeprogrammedfortherightchannelshouldhavecapacitors
insertedinthe1Rconnectingsockets.Whencapacitorsareinplaceforeachfrequencyand
channeltobeequalized,thelevelcontrolsmustbeadjustedtothedesireddegreeofboost
orcut.Atthispoint,makeaninitialsettingoftheHIGHFREQUENCYCOMPENSATIONcon-
trolstosimulatewhichtypeofoverallresponsecurvedesired,(A,B,orC).
Todeterminetheresultsoftheequalizingprocess,theresponsemustbecheckedagain
withtheanalyzer.Ifyouareusingananalyzerwitha continuousdisplay,thecontrolsmay
beadjustedandresultsseenimmediately.Ifyouareusingananalyzerthatindicateswith
ameter,thecontrolsmustbesetinanintermediatepositionandtheresultsplottedona
graph.Afterplottingthefirstresponsecurve,youcanthendeterminetheneedforfurther
adjustmentsbyrunninganotherresponsecurve.Thisprocedureshouldberepeateduntilyou
arriveattheresponsedesired.
Dependingonwhethera wideornarrowbandisused,andhowmuch amplitudeispro-
grammedwillaffecttheoverallshapeoftheresultingresponsecurves.Itispossibleforthe
responsecurvesoftwonearbyfrequenciestooverlap.Readjustmentsmustoftenbemade
withrepeatedresponsemeasurementsuntil thefinaldesiredresultisachieved.TheHIGH
FREQUENCYCOMPENSATIONcontrolswillbevaluableinsettingthedesiredhighfrequency
slopetobestmatchthelisteningrequirements.
Ifoneequalizationsectiondoesnotprovidesufficientequalizationamplitude,a second
sectioncanbecascadedandprogrammedtothesamefrequencytodoubletheamplitude
ina particularfrequencyrange.Theduplicatesectionmustbeina differentbankofsections
fromthefirst.Thefirstbankofsectionsis1 through4,andthesecondbankis5 through7.
Oncetheprogramminghasbeenfinished,andthedesiredresultsachieved,thecovershould
bereplacedontheMQ108.NoadjustmentsorchangesshouldbemadetotheMQ108pro-
grammingwithoutusingananalyzertochecktheresults.
9
HOWTO
PROGRAM
THEMQ108

(AllspecificationsarevalidwiththeMQ108setforflatresponse.)
FREQUENCYRESPONSE
+0,-0.5dBfrom20Hzto20,000Hz
RATEDOUTPUT
2.5V
OUTPUTIMPEDANCE
Balanced:100ohms
Unbalanced:250ohms
MAXIMUMVOLTAGEOUTPUT
8Vfrom20Hzto20,000Hz
TOTALHARMONICDISTORTION
0.002%maximumfrom20Hzto20,000Hzatratedoutput
SENSITIVITY
2.5Vfor2.5Vratedoutput,(0.5VIHF)
SIGNALTONOISERATIO,A-WEIGHTED
105dBbelowratedoutput(95dBIHF)
MAXIMUMINPUTSIGNAL
Highlevel:8V
INPUTIMPEDANCE
22,000ohms
HIGHFREQUENCYCOMPENSATION
±10dBat20,000Hz
PROGRAMMABLEFILTERS
14sections(7perchannel),eachofwhichcanbeprogrammedfor1/3octavecenterfre-
quencies(narrow),or1 octavecenterfrequencies(wide),from20Hzto1000Hz.Amplitude
iscontinuouslyadjustable± 12dBfornarrowand± 15dBforwidewithcontrolsdetented
forflatresponse.
SIZE
2.88inches(7.3cm)H,13.6inches(34.5cm)W,7.65inches(19.4cm)D,includingclearance
forconnectors
WEIGHT
5.5pounds(2.5Kg)Net
10
SPECIFICATIONS

25
20
15
10
5
0
-5
ResponseindB
-10
-15
-20
-25
20 100
FREQUENCYINHERTZ
1000020000
ResponseindB
20
10
-10
-20
20
FREQUENCYINHERTZ
1000020000
11
RESPONSE
CURVES
1000
TYPICALFILTERRESPONSE
CHARACTERISTICS
200HertzFiltersShown
TWONARROWCASCADED
NARROW
WIDE
HIGHFREQUENCYCOMPENSATIONRESPONSE
(SETATMAXIMUMANDMINIMUM)
0
100 1000

90
80
SPL
IN
dB
60
50
LEFT
SPEAKER
SuggestedEqualizationCurves
12
BANDFREQUENCYINHz
20
25
31.5
40
50 63 80
100
126
160
200 250 315 400 500
630
800
1k
1.25k
1.6k
2k
2.5k
3.15k
4k
5k
6.3k
8k
10k
12.5k
16k
20k
70
RESPONSE
CURVES

USEFORCHARTINGLOUDSPEAKERTESTS.
SPL
IN
dB
90
80
70
60
50
RIGHTSPEAKER
SPL
IN
dB
80
70
60
50
13
GRAPHS
90
LEFTSPEAKER

USEFORCHARTINGLOUDSPEAKERTESTS.
LEFTSPEAKER
80
SPL
IN
dB 70
60
50
RIGHTSPEAKER
SPL
IN
dB
80
70
60
50
14
GRAPHS
90
90

04012400