Access VIRUS|POWERCORE User's Reference Manual page 78

The maximum pre-delay times available depend on the reverb type, ranging from 150ms
(Hall) to 500ms (Ambience).
> CLOCK
Selects a clock-synchronised pre-delay time. This is particularly useful for the Reverb+Feed-
back algorithms, as the repeats can be synchronised in the same way as in the delay. (See
Delay Clock for further explanation.)
> FEEDBACK
This parameter is only functional in the Reverb+Feedback modes. It determines the amount
of signal to be fed back into the reverb. Higher values result in more repeats of the early
reflections. To emphasise this effect, try using short reverb times and a long pre-delay.
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