Problems arising from using DSP processor
and external volume controller residing in same audio system.
The problem with running a VOL box and a DSP processor together is that when a Mixer with echo canceller (like the Vortex or XAP) are in a system, if the volume level changes via the VOL3 (or any similar) box, the echo canceller doesn’t know about it because the level change occurs outside of the DSP. The louder volume effectively changes the physical echo reference level (room volume) the echo canceller uses, and causes immediate echo that slowly decays as the DSP auto-adjusts the internal echo ref. level to compensate. This echo problem usually occurs every time the volume level is adjusted, but is worse when the volume is ramped UP to a louder level. This can not only cause echo, but feedback and harsh “ringing” during the same period of time. It’s not pleasant, and should be avoided. A VOL box is great only if there are no DSP processors to perform volume changes. Technically, I suppose that running both wouldn’t be a problem if the DSP is not being used for echo cancellation or feedback reduction, but generally speaking, that is usually not the case.
