Mackie DLM8 - Smart Protect; Limiting Function; Overexcursion Protection; Thermal Protection System

Owner’s Manual
15
Owner’s Manual
Smart Protect
ThereareadvancedDSPprotectionmechanisms
designedintotheDLM8/12tosafeguardthe
loudspeakersandampliersfrominadvertentdamage.
Theprotectioncircuitsaredesignedto 
protecttheloudspeakersunderreasonable
andsensibleconditions.Shouldyouchoose
toignorethewarningsigns[e.g.excessivedistortion],
youcanstilldamagethespeakerbyoverdrivingitpast
thepointofamplierclipping.Suchdamageisbeyond
thescopeofthewarranty.
Limiting
Thedriverhasitsowncompressioncircuitwhich
helpsprotectitfromdamagingtransientpeaks. 
Thecompressorisdesignedtobetransparentand
isnotnoticeableundernormaloperatingconditions.
ThefrontLEDwillpulsewheninlimit.Turnthe
volumedown!
Overexcursion Protection
A36dB/octavehigh-passlterjustpriortothelow-
frequencyamplierpreventsverylowfrequenciesfrom
beingamplied.Excessivelow-frequencyenergycan
damagethewooferbycausingitto“bottomout,”also
knowasoverexcursion,whichisequivalenttoa
mechanicalformofclipping.
Thermal Protection
Allampliersproduceheat.DLMloudspeakersare
designedtobeefcientbothelectricallyandthermally.
Theampliermodulehasinternalheatsinksand
adigitallycontrolledvariablespeedfan.AstheDSP
recognizesvaryinginternalheatlevels,itwillturn
onatanappropriatespeedtodrawcoolairinover
theamplierandexitviathesidevents.
Intheunlikelyeventoftheamplieroverheating,
abuilt-inthermalswitchwillactivate,mutingthe
signalandrampingthefanuptotopspeed.Anerror
messagewillalsoappearontheOLEDDisplay:
Whentheamplierhascooleddowntoasafe
operatingtemperature,thethermalswitchresetsitself,
andtheDLMloudspeakerresumesnormaloperation.
Ifthethermalswitchactivates,tryturningdownthe
levelcontrolanotchortwoonthemixingconsole(or
thebackoftheloudspeaker)toavoidoverheatingthe
amplier.Beawarethatdirectsunlightand/orhotstage
lightsmaybetheculpritofanamplieroverheating.
FYI
TheFYIscreendisplaysthelatestUIversion,DSP
version,AmpB+[voltage]andcurrenttemperature.
Nothingmaybechangedorupdatedhere,justanFYI
asstated.Thisscreenisdisplayedwhenpressingthe
Channel1[11]andMEMbuttons[14]simultaneously.
AC Power
BesuretheDLMloudspeakerispluggedintoan
outletthatisabletosupplythecorrectvoltagespecied
foryourmodel.Itwillcontinuetooperateatlower
voltages,butwillnotreachfullpower.
Besuretheelectricalservicecansupplyenough
amperageforallthecomponentsconnectedtoit.
Werecommendthatastiff(robust)supplyofAC
powerbeusedbecausetheampliersplacehigh 
currentdemandsontheACline.Themorepowerthatis
availableontheline,thelouderthespeakerswillplay
andthemorepeakoutputpowerwillbeavailablefora
cleaner,punchierbass.Asuspectedproblemof“poor
bassperformance”isoftencausedbyaweakACsupply
totheampliers.
Beawareofanyerrormessagesthatmaybedisplayed
ontheOLEDDisplay:
Neverremovethegroundpinonthepower
cordoranyothercomponentoftheDLM
loudspeaker.Thisisverydangerous.