page 4 – 28
VP-8IP / Sep 2013
V P - 8
i P
P R O G U I
or wrong setting of the Gate controls unless that setting causes undesired, unexpected,
or unwanted behavior of the processor during low level program passages.
InterBand Coupling
The
VP‑8
iP
utilizes interband coupling to ensure
that the audio spectrum remains well controlled
under all programming conditions. What this means
is that the gains of bands 1, 2, and 4 can never be
greater than the difference between the gain in
band 3 and the setting of the
InterBand Coupling
control, which ranges from -30.0dB to 0.0dB.
Example: Suppose that the
InterBand Coupling
control has been set to a setting of
-3dB. Under this condition bands 1, 2, and 4 can never have a gain that is more than
3dB greater than the gain in band 3.
Another example: Suppose that the
InterBand Coupling
control is set to -5dB. If
band 4 now becomes un-gated because its level is sufficient to do so and band 3 is busy
enough to be requiring 12dB of gain reduction, band 4 cannot have a gain that is more
than 5dB
higher
than the gain in band 3, which means that it’s gain cannot increase
beyond -7dB (12dB gain reduction in band 3 minus the 5dB from the
InterBand Coupling
control setting).
The
InterBand Coupling
control works in one direction only and does not affect a
band’s ability to reduce its gain when appropriate.
AGC Backoff
The AGC Backoff adjusts the processing balance between slower AGC action and
faster compression. Think of it as the “density” control.
With the AGC Backoff control set at 0, the audio gain control is primarily due to
slower AGC action, and therefore short term program dynamics are largely unaffected
unless they exceed the AGC gain reduction by at least 1dB. In that case momentary gain
reduction by the compressor will place the gain where it needs to be to return control
to the AGC.
With the AGC Backoff control at the other extreme, or -12dB, gain control is primarily
due to fast compression and short term dynamics will be aggressively controlled.
The setting of the AGC Backoff control allows the audio compression texture to be
modified from a gentle, almost unobtrusive control (AGC Backoff between “0” and
about minus 3.0dB), to very obvious compression (AGC Backoff control at “-4.0” or
greater negative numbers) creating a sound that is similar to vintage compressors and
limiters from the 1960’s.
Note that regardless of the setting of the AGC Backoff control, the AGC and Compressor
stages operate with their algorithms linked mathematically and there is no method for
changing the relative thresholds between the AGC and compressors. If for some reason
less AGC control signal is desired, it may be achieved by lengthening the AGC attack
time to large or very large values.
