Manual

4.1 BasicOperation 4 THE OXFORD DENOISER
profile that is flat, generally speaking, whereas an audio track with brown noise
embedded into it would need a noise profile that is higher at the LF end.
The noise profile is used to gate-out components of the frequency spectrum that are
below it, and keep the components that are above it. The overall level of the noise profile
relative to the input signal is adjusted by the Threshold control to determine what is
gated out. Therefore, to achieve good results, a suitable setting for the Threshold control
needs to be found that pitches the threshold well below valid signal components, but well
above the noise floor. If Threshold is set too high, some of the signal will be attenuated; if
it is set too low, the noise removal will be less effective.
The Oxford DeNoiser provides different means to arrive at an appropriate noise profile.
The default method is called Auto mode. In Auto mode the frequency spectrum of the
signal is examined to automatically acquire the general shape of the noise profile by
looking for levels in the frequency spectrum that are consistently there. In Auto mode the
threshold level is a value relative to the general signal level. The advantage of Auto mode
is that the threshold follows the signal level so that noise removal will always be a fixed
number of dBs below the level of the actual signal. As the level of the material dips closer
to the noise floor, it does not get removed along with the noise.
Another method to arrive at an appropriate noise profile is to use the Freeze button to
freeze the automatic noise profile, and use that fixed profile from then on. This is useful
for capturing the profile from a section of material containing only background noise, and
then applying it to the rest of the material. In Freeze mode, both the noise profile and the
level at which it is applied are fixed. The advantage of Freeze mode is that the threshold
is always set to remove the correct level of noise from the material, meaning that as the
level of the material climbs, the noise removal is less destructive. However, as the level of
the material dips closer to the noise floor, more and more of the actual material gets
removed along with the noise.
A third method is to use Manual Mode. In this mode you manually specify a simple
coloured noise profile. In Manual mode, both the noise profile and the level at which it is
applied are fixed.
Generally, you will want to leave the Auto mode on because in this mode the level of the
threshold will follow the general level of the signal, and this tends to give the most
sympathetic results.
www.sonnox.com 35 Gotocontents