TC Electronic SYSTEM 6000 MKII Algorithm Manual

107
bACkDrOP - TuTOrIAl
controls and to listen to the amount of noise reduction,
the occurrence of musical noise, and the smearing of
transients (signal distortion). These variables must be
balancedwhenusingBackDroptoremovenoisefrom
youraudio.Fortunately,BackDropprovidesyouwitha
comprehensivesetoftoolstomaketheoptimalpossible
trade-off.
WhenusingBackDrop’scontrolsitisimportantto
rememberthatAggressionandMaxReductionwork
togetherandsoyoushouldgobackandforthbetween
these parameters in order to find the best settings. This
also applies to the Basilar Dispersion and Transient
Recoverycontrolswhichworktogether.
Advanced Use
The tutorial in the previous section was intended to give
youafeelforsomeofBackDrop’scontrols.Inthissection
we endeavor to provide you with some guidelines for
obtainingthebestpossibleperformancefromBackDrop.
The following steps have been found to be a suitable
approach for getting good performance under almost
all circumstances. As you become more familiar with
BackDropyouwillnodoubtdevelopyourowntechniques
andstrategiesthatworkbestforyou.
As always, the first step in the noise reduction process
is to capture a sample of the audio for the noise print
information. It is very important that the audio used to
calculate the noise print information contain only the noise
and none of the signal.
With the noise print information calculated, use the
AlgorithmModelcontroltoselecttheBackDropalgorithm
(Basic, MultiBand or MultiType) that is best suited to the
noise you are trying to remove.
BackDrop’sfundamentalphilosophyistotargetthenoise
reduction to where it is needed most and to apply as little
processing as possible to the signal. The strategy outlined
inthissectionisinkeepingwiththisphilosophy.Generally
speaking,togetthebestresultsfromBackDrop,donot
be“overaggressive”.Trytouseaslowanamountof
aggression, and Max Reduction as possible, and use a
moderate amount of Basilar Dispersion (40% to 60%).
It is useful to begin by getting an idea of how much noise
reduction is necessary for the audio sequence that you
areworkingon.Inmanycasesreducingthenoisebyonly
afewdecibelswillmakeadramaticimprovementinthe
quality of the audio sequence. In most cases, you will
not need more than about 10 dB of noise reduction. To
determine how much noise reduction is necessary, set
Basilar Dispersion and Transient Recovery to 0%. Set
Aggression to 100% and Max Reduction to 0 dB. Slowly
increase Max Reduction and listen as the level of noise
goesdown.UsetheBypassbuttontoturntheprocessing
onandoff.AdjustMaxReductionuntilyouobtainthe
appropriate amount of noise reduction.
With Aggression set to 100%, you are probably applying
more processing than necessary for the amount of noise
reduction that you desire. Therefore, slowly lower the
amount of Aggression until you here the level of the
noise floor begin to increase. This level of Aggression
corresponds roughly to the amount of reduction that you
desire and the value of Max Reduction that you have
selected. Note that this relation between Aggression and
Max Reduction depends on the signal being processed and
so the relative settings will be different for different audio
sequences.
ItisnowagoodtimetomonitorBackDrop’soutputvery
carefully and decide the following:
Isthistoomuchnoisereduction?Oftenitisdesirable
toleavesomebackgroundnoiseinthesignalsothatit
doesn’tsoundunnaturallyclean.Thisisprimarilytruefor
anoverallmixedsignalratherthanforindividualtracksthat
are yet to be mixed together.
Doyouhearanyartifacts?Ifyouhearartifactsthen
increase the amount of Basilar Dispersion until the level
of the artifacts becomes acceptable or the artifacts
becomes completely inaudible. In some cases, increasing
the amount of Aggression slightly when applying Basilar
Dispersion can also reduce the artifacts. You can also
takeadvantageofsomeoftheresidualhisstomask
artifacts created by the process itself. By using a little less
noise reduction and aggression, leaving a small amount
of residual hiss, you will have a harder time hearing any
artifacts.
Arethetransients(attacks)beingsmeared?Ifincreasing
the amount of Basilar Dispersion has caused a smearing
of the transients then you may want to increase the level of
Transient Recovery. It should be noted that higher levels of
Transient Recovery can cause some of the musical noise
to reappear. Therefore, Basilar Dispersion and Transient
Recoveryneedtobeadjustedtogetherinordertominimize
both the musical noise and the smearing of transients.
Are you losing the sound quality or clarity of the original
source?Itiseasytobecomeveryfocussedonthetaskof
removingnoiseandoverlookthefactthatthesignalhas
become somewhat distorted (altered). Remember to listen
tothesignalaswellasthenoise.Youwillneedtostrikea
balance between the amount of noise reduction possible
and the effect on the sound quality of the music. Keep in
mindthatBackDropwasspecificallydesignedtoenable
youtomakethebestpossibletrade-offforyourapplication.
You should be aware that when removing noise it is
commontouncoverlow-levelsoundsthatyoumightthink
areartifactsresultingfromBackDrop.Frequentlythese
sounds are actually part of the original signal but they were
partiallyhiddenbythenoise.UsetheBypassbuttonto
compare the processed signal to the original signal to see
if the sound was actually part of the original.
Whilekeepingtheabovepointsinmind,youshouldgo
backandforthbetweenthevariouscontrolsandadjust
them until the optimal noise reduction solution is reached.
Ofcourse,youshouldtryallthreeofBackDrop’salgorithm
modelstodeterminewhichoneisbestsuitedforthetask
at hand. Remember that you can switch instantly between
the algorithm models and the settings for each model are

TC Electronic SYSTEM 6000 MKII Specifications

General

Brand	TC Electronic
Model	SYSTEM 6000 MKII
Category	Computer Hardware
Language	English