Boss GT-X - Noise Elimination-Recording Onto Computer; Hi-Tech Noise Elimination

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Section9NoiseElimination
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©Copyright2000-2002BarryS.Pearceetal.  56
Be careful though, remember that peak limiters, limiters,
andcompressorscanalterdynamicrangestogivethissort
of pattern. It is best to check for clipping without these
devicesinthewayifyoucan.
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InthewaveeditoritwasverynoticeablethatalthoughIhad
aniceloudsignaltherewasasignificantclippingatabout
95%.AsIjustsaid,thisisindicativeofdrivingthecardtoo
hard. But the clip indicators didn't show. Well, that's
Cakewalkforyou.
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WhilstSoundForgestilldoesn'tshowclipping,Iuseditto
monitorthesettingupofrecordlevels,asSFgivesthepeak
asafigurenotjustameter(youhavepeakhold!).HereSF
showedapeakat-0.4dB.Seemstobeabittight.Indeedon
playbackclippingisevident.IreducetheMasterOutfader
onthemixingdesk(therealonenottheCakewalkone!)so
the peakis nowat -2dB. Don'tworryabout changing the
levels in the Volume Control dialog box in windows—If
youaredrivingthecardtooharditwon'tmatterwhatyou
doonwindows.
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SoIturndownthemasterfader.Mostoftheproblemhas
been alleviated. But even with a max peak at 87% there
appearedtobeseveralpeaksthatlooked 'chopped'atthis
limit. I am still suspicious of a clip. Indeed, with this
particularpieceIamplayingitisaroundthesebitsthatthe
monitorspeakersshowsomekindofdistortion/rattle.
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Hmm. There is so much headroom that it can't be the
mixingdeskoutput,andthemixingdeskcertainlyhasbeen
correctlysetupsoitsnotclippingonthePC—itmustbe
elsewheredowntheline.
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At this point I checked the sound from the speaker
cabinets—didthisclip?Idon'tthinkso.Nowthedifference
hereisthatthetwosignalpathssplitatmyPalmerPGA-05.
So Iturn downthe filtered outputlevels—thisaffectsthe
levelgoingintothedesk.Icheckagainandtheclipisstill
present.Iresetthevolume(noIdidn'tbalancethedeskfor
thenewlevelincaseitwasthedeskinputthatwasbeing
clipped).OK,sothenextunitdownthelineistheGT-3—
hangon, this feeds bothsignalpaths - theclip cannotbe
herecanit?I'vecheckedtheGT-3metersandeverythingis
fine.OK.Butyouhaven'tgotametershowingtheoutput
AFTERtheexternalcontrolknob.Ifyouturnthistozero
the master output level which is shown on the meter
remains—itdoesn'tdrop.Thereforeyouneedtobecareful
asyouhavenorealindicationoftheactualoutputvolume
fromtheGT-3.
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MaybeIamdrivingthePGA-05toohard.Buthow?Surely
the amp would amplify the PGA-05's problem. The trick
liesinthefactthat,asIsaidearlier,thePGA-05hasathru
jackandfilteredoutputs.IfyouswitchtheunitOFFthethru
jackskeepworking.SoIturndowntheGT-3'slevelandre-
record. The problem has disappeared from both the
recorded.wavandthemonitors.
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IcannowsetuptheGT-3soitdoesn'tclipthePGA-05,the
PGA-05 so it doesn't clip the desk and finally use the
MasterOutfaderonthedesktoavoidclippingthesound
card.
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Althoughyoumaynotberunningsuchaset-up,youmay
haveasimilarset-upwithadigitalmulti-trackersuchasthe
RolandBR-8oraTascam.Theprinciplesarebasicallythe
same,thedetailsjustneedadaptingtoyourparticularset-
up.
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Youcanalsohelpyourselfavoidclippingbyknowingand
understandingthetechnicalspecsofyourequipment,where
equipment specifies max output/input levels and nominal
output/inputlevelsyoucanseewhetherornotoneunitwill
overdriveanother.
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Phew.Thatcoveredalotaswell.Ihopebynowthatyour
systemisnowniceandquietnoisewiseandadditionallyis
nowfreefromclipping.
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Please let me know if you have any further advice.
Especiallyregardingspecificunitsyouhavehadaproblem
with which needed a slightly different solution than that
whichIhavedescribed.
NoiseElimination—Recording
ontoComputer
Well, this is going to be quite a quick follow up to our
discussionsonnoiseelimination.
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Ifyouarerecordingnearorontoacomputeritispossible
thatyourpickups(especiallysinglecoils)willbepickingup
alot ofnoise. Most(probably80-90%)ofthatnoisewill
comefromthecomputermonitor.Thuswheneveryoucan,
switch the monitor OFF. What I do is set the software
recording,obviouslygivingmyselfplentyoftimebeforeI
needtoplay.Ithenswitchthemonitoroff–letthenoise
subside and then start recording. When I've finished
recording I then switch the monitor back on. This can
eliminateahugeamountofnoise.
Hi-TechNoiseElimination
ManyofyouhavecomputerswithsoftwaresuchasSonic
Foundry’sSoundForge.DidyouknowthatSFcomeswith
aspectrumanalyser?Evenifyoudon’thaveSFthenthere
areanumberoffreebieanalysersoutthereontheweb.You
can use these spectrum analysers to assist in eliminating
noise rather than turning up volume controls. It is much
moreaccurateandyouinstantlygettoseeifsomethingyou
pluggedinhascausedagroundloopornot.