8.0

Noise Reduction: Denoiser and Dehisser
DeNoiser
The DeNoiser is especially useful for clearing long-lasting disruptive noise like mains humming, hissing,
noises from sound charts, disturbance noise from ground circuits, interference from audio-equipment with
high mic outputs (record players), impact noise, or the rumbling of records.
The DeNoiser requires a noise sample. Some typical sounds are at your disposal.
Set the degree to which the noise should be reduced with the fader. It is often better to reduce
interference signals by 3-6 dB rather than as much as is possible so as to keep the sound "natural".
Another possibility is to create a noise sample yourself. You need a short sample from the sound track in
which only the background noise can be heard. Then switch to the DeNoiser dialog with the "Advanced"
button.
Step 1: Select noise sample
First you have to select a noise sample of the noise you want to remove.
You have two options:
Pick out typical background noise:
You can select and use a number of typical background noises from the flip menu. Select one and listen
to it via the "Play" button. If it is similar to the background noise in your sound track, go ahead and use it
(see "Step 2: Removing background noise").
Extracting a new noise sample from a sound track:
You can also pick out a short passage (from the existing sound track) in which you can hear the
background noise.
Automatic search:
Searches especially quiet passages in which background noise most probably resides.
Previous/play/next:
These buttons allow you to play all of the passages found for easy comparison.
Save as:
Once found, you can save noise samples on the hard drive which then appear as an entry in the "Typical
background noises" drop-down menu to be used in other projects. There's no need to save it if you only
want to use it once, and in this case switch to "Remove background noise".
If you only want to use the noise sample in the current project, then you don't have to save it. You can
immediately switch to the "Remove category".
Step 2: Remove background noise
Noise level:
The level of the noise reduction function should be set as precisely as possible. Low settings result in
incomplete deletion of the hissing. An incomplete deletion of the hissing produces artifacts and should be
avoided. High settings produce dull results and useful signals which are similar to hissing (woodwinds, for
example) are also filtered away. It's worth your time to find the best setting.
Reducer:
Here you can set the balance between the original signal and the signal with depressed interference. It is
often better to reduce interference signals by 3-6 dB rather than as much as is possible so as to keep the
sound natural. For buzzing it's best to apply complete removal.
Dehisser
The DeHisser eliminates regular "white" noise typically produced by analog tape recordings, microphone
pre-amplifiers, A/D converters, or transformers.
Noise reduction can be regulated in decibels with the fader. It is often better to reduce interference
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