Assuming you are only passing the front 2 channels from a surround processor through the integrated amp, you need to use the volume control in the processor. The VC in the amp should be kept at a fixed setting.
Kal is correct. When you set up the speaker levels on the processor, you need to have the volume control on the integrated amp set to a pre-determined fixed level, like top dead center or 5 or something like that. Then ever time you play HT sources through the processor, you'll first need to set the integrated amp's volume control to that pre-determined level.
Having 2 volume controls would not degrade sound?
So keep volume control on amp constant, and adjust volume on processor?
But, why not the other way around, keep volume control on processor constant and keep processor volume fixed?
In other words:
Could I change the volume on processor, and measure the voltage of the output on the processor so that it matches the voltage output of, say my CD player. Then have processor volume control fixed at that level/voltage, then just vary the volume control on the amp?
(Hope this makes sense)
Sorry Spoolyt, it doesn't make sense to me.
For listening to 2-channel music you would want all of your 2-channel sources connected directly to the integrated amp. That eliminates the processor completely from the equation and minimizes potential sound degrading circuitry that is not needed for 2-channel playback.
When listening to HT sources in surround sound, your integrated amp will only function as a power amp. All volume levels for the speakers attached to the integrated amp and other surround channel amps would have to be controlled by the processor. That is the only way to maintain the relative volume levels for the front L&R speakers powered by the integrated amp, plus all of the other surround speakers.
Regarding your question about 2 volume controls degrading sound, I would guess you would want to minimize any potential degradation to 2-channel sound vs. surround sound. Connecting all of your 2-channel sources directly to the integrated amp would accomodate that. The 2-channel signal would not flow through the processor and the processor would not even need to be turned on during 2-channel playback. You would only have the potential for any sound degredation when playing multi-channel sources through the processor (with the integrated powering the fron L&R speakers). This is typically considered the best compromise and you would likely not hear any difference anyway.