Wheatstone Corporation E1, Техническое руководство, Страница: 44 / 92

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E-1 / Apr 2010
M A S T E R P A N E L
Compressor Settings
The compressor algorithm used in the E-1 is designed to:
- prevent really ghastly noises from being achieved too easily;
- allow smooth, inaudible, and unobtrusive level control on uneven sources;
- be able to act as a peak limiter for inadvertent overload control;
- enable deep effects if required.
The E-1 compressor section is a compound of many diverse dynamics elements.
The level detector is a pseudo-RMS averaging type with its own symmetrical-in-
time attack-and-release characteristic adjustable between 0.1mS and 330mS (“Attack”
control). At the slower end of its range, by itself it achieves a nouveau-classic “dbx”
style syllabic-rate level control. As the time-constant is shortened, it becomes progres-
sively shorter in relation to the lower audio frequencies themselves; the effect is to
turn the detector into more of a peak-level detector, necessary for limiting or wilder
effects. A secondary effect at intermediate to fast attack-times is that low frequencies
are peak sensed while high frequencies are average sensed, resulting in an effective
high-frequency bias (up to as much as 6dB differential) which helps to mitigate the
detrimental limiting effect of the resulting audio seeming “bottom heavy” that is normal
to most compressors.
While the overall gain-reduction scheme is “feed-forward,” the heart of the detector
stage itself is a feedback limiter; this allows for this carefully-contrived loosely-damped
servo-loop to permit far more interesting dynamic effects than the analytically perfect
but deathly boring deterministic classic feed-forward detection schemes typically afford.
The compressor is “soft-knee,” meaning the compression ratio increases slowly
with increasing applied level, greatly easing the sonic transition into full compression;
it helps avoid the “snatching” and “pumping” at threshold that many “hard-knee” dy-
namics units exhibit.
A full range of controls is available to affect the compressor’s behavior:
COMPRESSOR — A switch that allows the compressor to be enabled and disabled.
GAIN — controls the input gain of the signal on this fader. For Mic input the range
is from 20dB to 80dB; for Line level input the range is from -18dB to +12dB.
THRESH (-40.0dB - +10.0dB) — Threshold, the level above which gain reduction
is applied.
RATIO (1.00:1 - 20.0:1) — The proportion by which a signal exceeding the threshold
is reduced in level. “3:1” means that a change in signal level above the threshold by
15dB will be reduced to only a 5dB change in level.
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E-1 / Nov 2012