TC Electronic Broadcast 6000 - Manual (Page 194)

Backdrop
190 System 6000 MKII Algorithms
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 pro-
cessing on and off. Adjust Max Reduction until
you obtain the appropriate amount of noise re-
duction.
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 Aggres-
sion until you here the level of the noise floor
begin to increase. This level of Aggression cor-
responds roughly to the amount of reduction that
you desire and the value of Max Reduction that
you have selected. Note that this relation be-
tween Aggression and Max Reduction depends
on the signal being processed and so the rela-
tive settings will be different for different audio
sequences.
It is now a good time to monitor BackDrop’s out-
put very carefully and decide the following:
Is this too much noise reduction? Often it is de-
sirable 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 accept-
able or the artifacts becomes completely inau-
dible. In some cases, increasing the amount of
Aggression slightly when applying Basilar Dis-
persion 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 aggres-
sion, 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 Re-
covery. It should be noted that higher levels of
Transient Recovery can cause some of the musi-
cal noise to reappear. Therefore, Basilar Disper-
sion 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 fo-
cussed on the task of removing noise and over-
look the fact that the signal has become some-
what 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 Back-
Drop. Frequently these sounds are actually part
of the original signal but they were partially hid-
den by the noise. Use the Bypass button to com-
pare 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 vari-
ous 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 preserved as you
switch, allowing you to compare your best set-
tings for each.
It is also a good idea to periodically use the Re-
moved button to hear what is being removed
from the input signal. If you hear components
of the signal, then this may be an indication that
you are applying too much processing.
Finally, if you are working on a stereo record-
ing, it is worthwhile to try using BackDrop in
both Stereo and M/S modes. For certain audio
sequences a dramatic improvement in quality
can be obtained by performing the noise reduc-
tion processing in the M/S domain. You should
note that, in order to get the most from the M/S
domain processing, the controls should be un-
linked so that different amounts of processing
can be applied to the Mid and Side signals. Spe-
cifically, it is often more perceptually beneficial
to apply more noise reduction to the Side signal
than to the Mid signal.