Mackie SRM1850 - SRM Subwoofer Rear Panel Controls - Part 1; Polarity and Gain Controls; Output Connectors

Owner’s Manual
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Owner’s Manual
SRM Subwoofer: Rear Panel Features continued...
4. Normal/Invert Switch [Polarity]
Thisswitchreversesthepolarityofthesignalgoing
intothesubwooferamplierby180˚.Ithasnoeffecton
thesignalattheoutputs.
Thereisnorightorwrongsettingforthisswitch.
Listentotheoverallblendofthesubwooferwith 
therestofthesystemandselecttheswitchposition
thatgivesyouthebestsoundforyouraudience.
Infact,yoursystemmayvarywhenpositioned 
differentlyandinalternatevenues.Don’tbeafraid
toexperimentwiththepositionofthepolarityswitch.
Seepage11formoreinformation.
5. Gain Knob & Sig / Lim LED
Thegainknobadjuststheinputsensitivityofthe
micinputs.Thisallowssignalsfromtheoutsideworld
tobeadjustedtorunthrougheachchannelatoptimal
internaloperatinglevels.Thereis–6dBofgainwiththe
knobfullydown(off),rampingupto6dBofgainfully
up(max).
Theaccompanyingdual-coloredLEDwillilluminate
greenwhentheinputsignalispresent,indicating
signal.Itwillremainlitsolongasthereissignalabove
–20dBupresent.
SRMsubwoofershaveabuilt-inlimiterthat
helpstopreventtheamplieroutputsfromclipping
oroverdrivingthetransducers.TheLEDilluminates
yellowwhenthelimiterisactivated.It’sokayforit
toblinkyellowoccasionally,butifitblinksfrequently
orlightscontinuously,turndownthegainknobuntil
itonlyblinksoccasionally.
Excessivelimitingmayleadto
overheating,whichinturntripsthe
thermalprotectcircuitryandinterrupts
theperformance.See‘ThermalProtection’on
page12formoreinformation.
6. High Pass Outputs
Typically,full-rangeloudspeakersareconnected
tothehighpassoutputsto“split”theworkwith
thesubwoofer.Thesubwooferhandlesallofthelow
frequenciesandtheloudspeakershandletherest.
Asaresult,itismoreefcientandabitlouder.
BalancedXLRmaleconnectorsareprovided
fortheline-levelAandBhighpassoutputs. 
Thesubwoofer’scrossoversplitstheinputsignalsinto
twofrequencybands.Thelowfrequencyrangebelow
20Hz–200Hzgoestotheinternalamplierthat 
powersthesubwoofer.Thefrequencyrangeabove
20Hz–200Hzissenttotheseline-leveloutputjacks.
Thefrequencyrangedependsonwherethehighpass
mode[9]isset.
Theyarewiredasfollows,accordingtostandards
speciedbytheAES(AudioEngineeringSociety):
Balanced XLR Output Connector
Pin1–Shield(ground)
Pin2–Positive(+orhot)
Pin3–Negative(–orcold)
7. Full Range Outputs
Connectthefullrangeoutputstotheinputsof 
anotherpoweredsubwoofer,poweredloudspeakers,
ortoanamplierpoweringpassiveloudspeakers.
BalancedXLRmaleconnectorsareprovidedforthe
line-levelAandBfullrangeoutputs.
Thesignalattheseoutputsisadirectcopyofthe
inputsignals.Theseoutputsallowyoutodaisy-chain
multiplesubwoofersand/orsendthefullrangesignals
toloudspeakers.It’sagreatwaytoaddsidells,too!
2
1
SHIELD
COLD
HOT
3
SHIELD
COLD
HOT
3
2
1
Balanced XLR Output Connector
SRM
550
SRM
650
VAR
POWER CONSUMPTION 200W
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