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
