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6. Denoiser
The Denoiser belongs to the so-called single-ended noise reduction systems. This means it
does not need any special coding procedure before recording, like in the famous tape noise
reduction system from DOLBY™ Lab. It is a tool that efficiently removes any kind of broad-
band noise from pre-recorded audio tracks. The Algorithmix® Denoiser is a weapon against
tape hiss, noise from telephone-call cuts, and residual noise from old records after processing
with the Descratcher.
In a single-ended noise reduction systems, the user decides which noise characteristics have
to be applied to the denoising process. A typical broadband noise profile, optimized for
surface noise of vinyl records as well as tape hiss, is used in this version of the Denoiser.
The noise reduction process in the Denoiser is controlled by just two parameters, allowing an
easy search for optimal results, depending on the given input signal.
The frequency spectrum of the input signal (red), the noise profile (white) applied to the
processed audio material, as well as the spectrum of the output signal after processing
(green) can be followed in the Analyzer window.
The noise profile (white) marks the threshold border, above which no noise reduction is
applied. The threshold parameter moves this noise profile up and down and can be used to
set up the profile just above the background noise level. For a given threshold, the second
parameter, called reduction, decides the amount of removed noise below the chosen noise
profile.
A good starting value for threshold is to set the noise profile just above the background noise
level (approx. 10 dB). A subsequent increase of the reduction parameter should significantly
reduce the background noise. If noticeable artifacts in the form of so-called singing or robot-
like sounds appear (time aliasing phenomenon), decreasing the reduction parameter and
increasing the threshold level (up to about 30 dB above the background noise) usually helps.
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Algorithmix® Sound Laundry™ TerraTec Edition (English)
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