JBL L100 CENTURY User manual

UBL
LSERIES
MANUAL

INSTRUCTIONMANUAL
INTRODUCTION
JBLcraftsmenhavebeeninvolvedintheart ofsoundformorethan
ageneration- signalandsource,woodandfabric,transducersand
acoustics- allofit.
Todaythesecraftsmencontinuetoperformtothemostrigid
standardsanycraftsmencansubmitto:thoseimposeupon
themselves.
JBLloudspeakersarecarefullyengineeredinstruments,pains-
takinglycraftedandassembledtowatchmakersstandards.JBL
enclosuresexpresstheexcitementofcreativedesign;theyareele-
gant,solidandflawlesslyfinished.JBLtransducersandelectronics
offerwhathasbeencharacterizedbydevotedmusiclistenersas
"theincomparableJBLsound".
Byfollowingthefewsimplesuggestionscontainedinthisbooklet,
youcanlookforwardtosuperbhighfidelityreproductionthatwill
retainitsclarityandrealismyearafteryear.
UNPACKING
Thepackingmaterialofyour L-Series speakershasbeendesignedto
protecttheloudspeakersfromanydamageduetoroughhandling
duringshipment.Westronglysuggestthatyoukeepthepacking
materialforfuturepurposes,incaseyouaremovingoryour
loudspeakersshouldrequireservice.
PLACEMENT
Thelisteningroomandthelocationoftheloudspeakerswithinthe
roomaffectsbasslevelandbassresponse,imaging, clarityand
overallqualityofsound.Noothersinglefactorhasthesamelevelof
effectonthefinalsoundquality.Theacousticsofthelisteningroom
aredeterminedbythedimensionsoftheroom,itsconstructionand
thefurnishingsitcontains.Roomsthathavedifferentdimensions
forceilingheight,lengthandwidthwillgivea moreeven,balanced
soundthanroomswherethedimensionsareequaltoeachother.
Thisisimportant,especiallyatlowfrequencies,astheroom
dimensionsdeterminethepatternofstandingwaveswithinthe
jom.
ConsultyourJBLdealerforinformationregardingtheuseofpro-
ductsormaterialsdesignedtocontrolcertainacousticproblems
causedbyroomsize,shapeorconstruction.Inmanycases,
significantimprovementinperformancecanbeachievedbycareful
attentiontoroomacoustics.
YourJBL L-Series speakersareabletogivea verysatisfyingsound
ina greatvarietyoflisteningroomswhensetupinanevensided
trianglewithrespecttothelistener.However,a carefulsetup
procedurewillalwaysberewarding,andforbestresultswe
recommendplacementwellawayfromtheboundariesoftheroom
withpreferablyminimum0.75m (30in)distancetothewallbehind
thespeaker,and0.75-1.0m (30-40in)distancetothesidewalls.
The"bookshelf-size L-Series speakers,L 20,L 40andL 90can
naturallybeplacedona bookshelformountedonthewallbya
suitablebracket.
Thebestpossiblesound,however,isachievedifthespeakersare
placedonrigidandopen,preferablyheavystandofappropriate
height(40-60cmfortheL 20andL 90,20-40cmfortheL 40).
Suitablestandsareavailable fromyourspecializedJBLdealer.
IfyouwishtoplaceyourJBL L-Series loudspeakerona bookshelf
pleasebeawarethattheportoftheenclosuresareplacedonthe
back.A smalldistancebetweenthebackoftheloudspeakerand
thewall(2,5cm,1 in)willensurethattheportisworkingproperly,
whilea completeclosingoftheventwillhavea minor,butaudible
effectontheperformanceofthedeepbass.
Agoodguidelinetopropersetupistostartconcentratingonthe
tonalbalanceofthesound,aimingforthemostneutralproduction.
Isthebasstoostrongortooweakcomparedtothemidrangeand
treble?Movingthespeakersaroundinrelativelylargesteps,
(20-30cmor8-12in)willchangetheperceivedtonalbalance.
Whena satisfyingbalanceisfound,a propersoundstageand
stereolocalizationisdevelopedbysmallermovementsofthe
loudspeakersincombinationwithanglingtowardsthelistening
position.
Thelarger L-Series loudspeakers(L90,L 100)comeinmirror
imagedpairs,butnotasspecificleftandrightenclosures.We
stronglyrecommendexperimentationinorderto findthemost
satisfyingoverallsound.Attentiontoeverydetailofthesetupwillbe
beneficialintermsofimprovedsoundquality.
YourauthorizedJBL L-Series dealer,willbyhappytohelpyouobtain
thebestpossibleperformancefromyouJBL L-Series speakers.
NOTE: Newloudspeakersrequirea certainamountof"exercise"
beforetheyperformtheirbest.A steadylevelofperformanceis
achievedafter8-12hoursofoperation,dependingonthenatureof
themusicandthe level. Shouldyouwanttospeedupthisprocess
youcanuseinter-stationFMnoiseasa signalduringperiodswhere
youwouldnormallynotbelisteningtothespeaker.Alternativelya
CDplayeron"Repeat"wouldbeanappropriatesignalsource.
CONNECTIONS
IMPORTANT:Whenconnectingordisconnectingloudspeakersfrom
anamplifier,theamplifiermustbeturnedoff.Makingconnections
whiletheamplifierisoperatingcouldseriouslydamagethe loud-
speakersystemandvoidthewarranty.Theamplifiermustalsobe
turnedoffbeforeconnectingordisconnectingcablesatthe
amplifierorpre-amplifierinputs.
1mm2(18AWG)insulatedwireistheminimumsizerecommended
forloudspeakerconnectionsupto5 meters(16ft).Beyond this
distance,heaviergaugewireisrecommended:1.5mm2(16AWG)
upto10meter(30ft)and2 mm2(14AWG)upto20meters(60ft).
TheserecommendationsaregivenasMINIMUMrequirements,and
generallyspeaking,thespeakerleadsshouldbeasshortas
possible.
Speakerwireandinterconnectcablesareimportantcomponentsin
anaudiosystem.Withallotherfactorsatanappropriatelevelof
qualitythespeakercableandtheinterconnectcablecanmake
significantcontributionstotheperceivedsoundquality.Careful
selectionofcableandinterconnectscanaddorsubtractmarked
shadingsinthetonalcharacter.Likewise,differentcablescanhave
quitea dramaticimpactonthedynamiccontrastsexperiencedby
listeners.
Thesamecarethatwasgiventotheinternalsystemwiringinthe
JBL L-Series speakersshouldbeaffordedtotheselectionand
applicationofthecablethatwillconnectthevariouscomponentsin
yoursystem.YourJBLdealerhastheexperienceandknowledgeto

recommendsuitableinterconnectsandspeakerwireto best
complementyoursystem.
Thelengthofthespeakerwirewilldependonthelocationofthe
loudspeakersandtheamplifier.Sincethefinalpositioningofthe
loudspeakerwillbedeterminedbycarefullistening,youmaywant
toarrangea temporarywiringlayoutthatwillallowthemovingofthe
loudspeakertoexperimentwith placement.Whenthebest loud-
speakerpositionisdetermined,permanentconnectionsmaybe
madeusingtheshortestcablerunspossible.Bothleftandright
speakerwiresshouldbethesamelength.Insomesystems,the
amplifiermaybelocatedneartheloudspeakersystemandmaybe
connectedusinga shortlengthofspeakerwire.Althougha relatively
longcablebetweenthepreamplifierandmainamplifierisrequired
bysucha hook-up,thebenefitofa shortamplifier-to-loudspeaker
connectionwilloftenoutweighthedrawbacks.
Connectionstotheloudspeakersystemaremadeattheterminals
locatedonthebackoftheenclosure.Theseterminalspermita
varietyofconnectionmethods.
Themoststraightforwardconnectionismadebydirectlyconnecting
cleanbarewire.Thiswaytheconnectionismadebystripping8-10
mmofinsulationofftheloudspeakerwireandpassingthebarewire
throughtheholeinthebindingpost.Ifthewireistoothicktopass
throughtheholeintheterminalinonesinglebundle,separatethe
copperwireintothreeequalbundles,thenpassthecenterbundle
throughtheholeintheterminal.Wraptheremainingbundles
aroundthebindingpostandtwisttogetherwiththecenterstrands.
Theknobcannowbetightenedsecurely,andanyexcesswirethat
isnotincontactwith thebindingpostsurfacesshouldbetrimmed
toavoidshortcircuits.
Averyconvenientwayofconnectionistheuseof4 mmbanana-
typeconnectors,whichare then, in turn, connectedtothebinding
posts. Bearin mind, however,thatthenumberofcontactpoints
shouldbekepttoa minimum,andatthesametimeeachcontact
shouldbeastightaspossible.
Forthesamereason,werecommendtheuseofthehighestquality
spadeconnectors,expertlyconnectedtotheselectedcables.
Spadelugswillmakethebestpossibleconnectionbetweenthe
speakerwireandtheloudspeakersystem,minimizinganycontact
resistancethatmightdegradethesoundeversoslightly.
Anyconnectioninanaudiosystemshouldnotbeconsidered"good
forever".Allconnectionsshouldbeinspectedandcleanedor
remadeperiodically.Frequencyofmaintenancedependsonthe
materialsinvolvedintheconnection,atmosphericconditionsand
otherfactors.Consultyourdealerforspecificrecommendations.
Itisessentialthatbothloudspeakersina stereosystemhavethe
samepolaritywithrespecttotheinputsignal(arein"phase").
JBL L-Series aredesignedtoproducea positivepulsewhena
positivesignalisappliedtotheredinputterminal.
Ifthedriverconesofthetwoloudspeakersdonotmoveinthesame
directionfora givenvoltageattheinputterminals,therewillbea
lackofstereodefinitionanda lossofdeepbass.
Werecommendexperimentingwiththepolarityofthespeakers,
sincerecordings,programsourcesorpoweramplifierscaninvert
thepolarityofthesignal.The"correct"connectionistheonethat
yieldsthebestaudibleresults.Besuretoreversebothleftandright
connectionstokeepthesystemsinpolarity.
BIWIRING
JBL L-Series loudspeakersmayalsobeconnectedtotheamplifier
usingtwolengthsofwire.Thebiwireconnectionmethodoffers
severaloptionsandadvantages.
Thesystem'sinternaldividingnetworksareelectricallyseparatedat
thelowfrequencytomidrange/tweetertransition.Externalstrapping
barsconnectthetwopartsofthenetworkwhena singlewire
connectionis used. Thesystemisshippedfromthefactorywiththe
strappingbarsinplace.Byremovingthebars,connectionsmaybe
madetotheindividualnetworksectionsusingtwowires(four con-
ductors)asshowninFigure1.Thewiresusedmaybeofthesame
typeforbothlowfrequencyandhighfrequencysections.The
advantagesarethatwireeffects(resistance,inductance,etc.)are
reducedandintermodulationoflowandhighfrequenciesinthe
cableareavoided.Specializedwiresforlowfrequencyandhigh
frequencysectionsmayyieldexcellentresultsinsomesystems.In
eithercase,lowfrequencycableshouldbeasshortaspossible,
andtheleftandrightcableforeachsectionmustbethesame
length. Ifthecabletoonespeakersystemislongerthantheoneto
theotherspeakerduetothedistancefromtheamplifier,makesure
nottowindtheexcesscableupintheformofa coil. Instead,tryto
arrangeitinfiguresofeight, asthiswillminimizetheinductanceof,,
thecablerunandthusminimizecablelossesathighfrequencies.
CAUTION: Neverconnecttwoamplifierstothesameloudspeaker
withoutfirstremovingthestrappingbars.Operatingtwoamplifier
channelswith thebarsinplacemayseriouslydamagethe
amplifiersandvoidthewarranty.
Fig. 1:Linput
LowFrequency
HighFrequency
Amplifier
Fig. 2:Linput
HighFrequency
LowFrequency
LowFrequencyAmp HighFrequencyAmp

Thebiwireoptionalsopermitspoweringthesystemwithtwoampli-
fiersasshowninFigure2.Fouridenticalamplifiers(ortwodual
channelunits)maybe used, althoughspecializedlowandhigh
frequencyamplifierscanofferclearadvantages.YourJBL L-Series
dealercanrecommendamplifiersthatbestsuityourneeds.Inall
cases, theleftandrightamplifiersforeachsectionmustbe
identical. Ensurethattheinputsensitivityofthetwoamplifiersis
equalorthatinputlevelcontrolsareprovidedtomaintainproper
lowtomid/highbalance.Iftwoidenticalstereoamplifiersarecho-
sen, eachamplifiermaybelocatedneara loudspeakeranddrive
lowfrequencyandhighfrequencysectionsthroughshortwireruns.
Bewarethatsomeamplifiersinvertthepolarityofthesignal.Input
polarityshouldbethesameforbothlowandhighfrequency
sections.Ifthepolarityisreversedtoonesection,a discontinuityin
thefree-fieldresponsewillbeapparentinthecrossoverregion.Feel
freetoexperimentwiththepolarityoftheindividualsectiontofinda
positionthatwillsuityoubest.Reversethepolaritytoeitherhighor
lowfrequencysectionsofbothloudspeakersifa problemis
suspected. Amplifierpolaritymarkingsmaynotensurecorrect
polarityconnections.
AMPLIFIERPOWER
RECOMMENDATIONS
TheJBL L-Series speakersarecapableofhandlingpeakpowersfar
exceedingthecontinuousratingspecifiedfortheindividual
speakers.
Thecontinuousratingsarebasedonaneighthourtestusing
broadbandnoiseshapedtosimulatethepowerdistributionof
music. Thepeakratingofapproximately4 timesthecontinuous
ratingindicatesthesystem'sabilitytohandletransientpeakswell
abovetheaveragepower'levels.
AmplifierpowerratingsareanINDICATIONofhowloudthesystem
willplaywithoutdistortion.Amplifierpowerisgenerallymeasured
withsteadystatetestsignalsandperhaps,inaddition,dynamic
measurementsintoresistiveloads.Unfortunatelynoneoftheseare
firmindicationsofhowloudthesystemwillsoundina given
listeningroom.
Forthesereasons,anamplifiershouldonlybechosenaftercareful
listening. Ifitispossibletoachievethedesiredvolumelevelwithout
distortion, thentheamplifierhassufficientpowerregardlessofthe
rating.
.Moreimportantthanthepowerratingisthequalityofsoundthe
amplifieriscapableof.Unfortunately,amplifierspecificationsare
nota reliableindicatorofsoundquality.YourJBLdealercanmake
recommendationsandarrangeauditionstoaidselectionofsuitable
amplification.
Ifthesystemissetupwithseparatepoweramplifiersforhighand
lowfrequencysections,theamplifierforthehighfrequencysection
canbeoflesspowerthantheamplifierdrivingthelowfrequency
sectionbecauseofthepowerdistributioninrecordedmusic.Asan
example:ifa 100wattlowfrequencyamplifieris used, a 50watt
highfrequencyamplifierwill"runoutofpower"atapproximatelythe
samelevelwhenplayingmusic.
Fusesorcircuitbreakersofanykindshouldnotbeusedbetween
theamplifierandloudspeakers.Allsuchdeviceswillseriously
degradethesoundqualityanddonotensureprotectionfrom
loudspeakerdamage.Thekeytosafeoperationisadequate
amplifierpowertoavoiddistortionatthehighestsoundlevels
required.
GENERALCARE
JBL L-Series loudspeakersystemsarefinishedinmaterialsthatwill
retainitsfinishformanyyearstocome.Occasionalcleaningwitha
clean, softclothwillmaintaintheoriginalbeautyofthefinish.
Onlylint-freecottonclothsshouldbeusedfordusting.Toremove
fingerprintsandsmudges,anammonia-freewindowcleanermay
be used. Applya smallamounttoa lint-freecottonclothandgently
cleanthesurface.Neveruseanyabrasivecleanersorstrong
chemicaltocleantheenclosure.Incaseofdeepscratchesor
damage,pleaseconsulta qualifiedfurniturerepairshop.
GRILLE
Thegrilleisheldinplacebya pinlocatedateachcorner.Toremove
thegrille,grasptwocornersandgentlypullthegrilleawayfromthe
enclosure.Toreplacethegrille,positionthemountingpinsonthe
cupsandgentlypressuntilthegrillemeetstheenclosure.Although
thegrillehasbeenengineeredtominimizeacousticalinterference,
highfrequencyresponseandstereoimagingwillbeimprovedby
removingthegrille.
Anydustonthegrilleshouldberemovedusinga cleaningbrushor
avacuumcleaner.
SERVICE
JBL L-Series loudspeakersaredesignedtogiveyearsoftrouble-free
service.Noperiodicmaintenanceisrequired.Ifa problemis
suspected, firstmakesureallconnectionsareproperlymade.Ifa
problemexistsinoneloudspeaker,reversethespeakerwirestothe
leftandrightsystem.Iftheproblemremainsinthesamesystem,
thenthefaultisintheloudspeaker.Iftheproblemappearsinthe
oppositesystem,thecauseisinanothercomponentorcable.
Loudspeakerconesordiaphragmsshouldnotbemovedby hand.
Thevoicecoilassemblyislocatedwithextremeprecisionandthe
clearanceisvery small. Anyattempttomovetheassemblybyhand
caneasilyforcethevoicecoiloutofalignmentandcausedistortion
orfailure.
Shouldyourloudspeakersystemeverneedservice,returnittothe
JBLdealerfromwhomitwaspurchased.Ifforsomereasonthisis
impractical, writedirectlytotheJBLCustomerServiceDepartment,
describingtheproblemasfullyaspossible.
DonotreturnproductstotheJBLfactorywithoutprior
authorization.Addresscorrespondenceto:JBLCustomerService,
80CrosswaysParkWest,Woodbury,NY11797.Telephone:
1-516-496-3400or1-800-645-7292.OutsidetheUnitedStates,
contactyourlocalJBLdistributor.

SPECIFICATIONS L20 L40 L60 L80 L90 •00
Frequencyrange (-6dB)
50Hz-30kHz 45Hz-30kHz 40Hz-30kHz 40Hz-30kHz 40Hz-30kHz 35Hz-30kHz
Frequencyresponse on axis 65Hz-20kHz±2dB 60Hz-20kHz±2dB 60Hz-20kHz±2dB 55Hz-20kHz±2dB 70Hz-20kHz±2dB 50Hz-20kHz±2dB
±30°horisontaldispersion ±2dBto10kHz ±2dBto10kHz ±2dBto10kHz ±2dBto10kHz ±2dBto10kHz ±2dBto10kHz
±10°verticaldispersion ±2dBto10kHz ±2dBto10kHz ±2dBto10kHz ±2dBto10kHz ±2dBto10kHz ±2dBto10kHz
Systemtuning 45Hz 40Hz 40Hz 38Hz 35Hz 30Hz
Sensitivity 86dB/lm/2,83V 88dB/lm/2,83V 88dB/lm/2,83V 89dB/lm/2,83V 90dB/lm/2,83V 90dB/lm/2,83V
Impedance 4ohms 4ohms 4ohms 4ohms 4ohms 4ohms
Driveunitcomplement
Woofer
706G 708H 2x706H 708H LE120H LE120H
Midrange 704H 705H 705H 705H
Tweeter 050TÌ 050TÌ 050TÌ 050TÌ 050TÌ 050TÌ
CrossoverFrequencies
2.5kHz
350Hz/2.5kHz 125Hz/2.5kHz 350Hz/2.5kHz 400Hz/2.5kHz 400Hz/2.5kHz
Recommendedamplifierpower 50-150W/ch 50-200W/ch 50-200W/ch 50-250W/ch 50-300W/ch 50-300W/ch
Dimensions,mm(HxWxD) 420x260x280 650x300x330 900x260x330 940x300x330 400x600x340 940x400x370
Weightkgs
12kgs 22 kgs 24kgs 27 kgs 27kgs 35kgs
JBLcontinuallyengagesinresearchrelatedtoproductdevelopmentandimprovement.Because
ofthis,newmaterials,productionmethodsanddesignrefinementsmaybeintroducedinto
existingproductswithoutnotice.Forthisreason,anycurrentJBLproductmaydifferinsome
• respectfromitspublisheddescription,butwillalwaysequalorexceedtheoriginaldesign
specificationsunlessotherwisestated.

UBL
JBLIncorporated.20630NordhoffSt.,Chatsworth,CA91311
HA HarmanInternationalCompany