NOISE GATE OVERVIEW.
Noise Gates may be used to cut the level of residual noise between sections of a
recording. While this is essentially a very simple effect, this Noise Gate has a
number of features and settings that allow it to be both effective and
unobtrusive and well suited to most types of audio.
SELECT FUNCTION: Select whether you want to ‘apply the Noise Gate effect’ or
‘test the noise level’, or read this help file (Help 1 - 3 and ‘Tips’).
LINK STEREO will process both channels of a stereo track the same and will only
gate audio when both channels fall below the gate threshold.
LOW CUT FILTER: Removes sub-sonic frequencies including DC off-set. DC corrected
tracking is used whether or not the Low Cut Filter has been selected.
GATE FREQUENCIES ABOVE: applies the gate only to frequencies above the set level
- may be useful for reducing tape hiss, but may also introduce a small amount of
‘phase distortion’. Setting this below 0.1 kHz will switch this feature off.
LEVEL REDUCTION: How much the gated sections are reduced in volume. Gating to
absolute silence may sound unnatural and ‘clinical’. The default -12dB will
provide significant reduction in the audio level of gated sections while
avoiding the ‘gate slam’ that is a common criticism of noise gates. If the Level
Reduction is set below -96 dB the gate will ‘shut’ to absolute silence.
GATE THRESHOLD: When the audio level drops below this threshold the gate will
‘close’ and the output level will be reduced. When the audio level rises above
this threshold the gate will ‘open’ and the output will return to the same level
as the input.
ATTACK/DECAY: How quickly the gate opens and closes. At the minimum (10 ms) the
gate will fully open and close almost instantly as the audio level crosses the
threshold. This could cause the gate to ‘flutter’ or ‘snap’. At the maximum
(1000 ms), the gate will begin to slowly open (fade-in) 1 second before the
sound level exceeds the Threshold, and will gradually close (fade-out) after the
sound level drops below the Threshold over a period of 1 second. Longer gate
times (up to 10 seconds) may be achieved using text input rather than the
The Gate level should be just above the level of the noise to be removed. If the
gate threshold is too high, sound that should be retained will be cut. If the
threshold is set too low, noise will be above the threshold and allowed through
the gate. -6dB (maximum) will cut even moderately loud sounds. -96dB (minimum)
will allow virtually all sound to pass.
For a suggestion of a suitable Threshold setting, select a portion of the track
that contains only background noise, then use the “Analyse Noise Level”
The default Attack/Decay of 250 milliseconds will usually produce good results.
If the noise cut-off sounds too abrupt, increase the Attack/Decay setting.
Longer settings are often better when a high degree of noise reduction is being
If the noise remaining after applying the effect is too great, either set the
Level Reduction lower or raise the Threshold.
- Analyse the noise level
- Test the gate on a short selection with the Level Reduction set to -100 dB
- Adjust the Gate Threshold if necessary and retest.
- Adjust the Level Reduction slider and test. For the most ‘transparent’
results, avoid setting the Level Reduction any lower than absolutely necessary.
- When you are happy with the settings, apply to the entire song.