User Manual

330 Audio Plug-ins
Freeze Button
This button enables Freeze mode for the noise detection circuit. In this mode the noise
fingerprint is calculated once (when the Freeze button is pressed). This mode is useful
for material with a constant noise component, and would typically be sampled when
the signal is absent and only the noise component is present.
In Button
This button enables the noise removal processing. It allows glitch-less comparisons
with and without the noise reduction. It is important to note that with this button "off"
(i.e. the noise removal processing is disabled), the noise detection circuit is still enabled
and the graphical display will still show the real-time frequency display and the noise
contour line.
HF Limit Knob and Touch Pad (Hz)
This displays and controls the frequency beyond which the attenuation is applied non-
dynamically. Scrolling the frequency down from the default of 22kHz will show a red
region in the frequency display that has a fixed attenuation. To the left of the HF Limit
line the noise removal circuit behaves as normal. To the right the signal is attenuated
by a fixed amount set by the attenuation fader. This mode is useful for band-limited
programme material. A good example is a low bitrate encoded signal, which might be
band limited to 12kHz. Due to the sharp discontinuity, the noise removal circuit can
introduce audible artifacts around the band limit, and setting the HF Limit frequency
slightly lower than the band limit will remove those artifacts.
Attenuation Fader and Touch Pad (dB)
The attenuation fader and touch pad determine the level of attenuation that the noise
removal circuit will apply in the range 0 to -18 dB. Generally this should be set so that
the noise reduction is pleasing. Excessive use of attenuation can degrade the signal
unnecessarily.
Output Level Meter (dB)
The output meter is designed to give exactly 1dB per LED for the top 18dB of dynamic
range, and 2dB per LED thereafter. There is a peak-hold feature that holds the highest
peak, helping to give a better impression of the working dynamic range.
Output Gain Trim Touch Pad (dB)
This allows you to reduce the output level by up to 12dB. Dithering is applied after
output gain control, so it may be necessary to reduce this value by a small amount to
avoid clipping.
Quick-Start Guide for the De-Noiser
1. Start with Sensitivity and Attenuation controls at the default positions (0.0dB and -
4.5dB respectively).
2. Select Auto mode if the noise varies in time; select freeze for a defined and static noise
fingerprint.
3. Adjust the Sensitivity to find the correct balance between being too low (not enough
noise is removed) and too high (too much signal is removed).
WaveLab 7