I have the British, not the American, but I think the function of the Voice knob does about the same thing across the range of models (maybe with slightly differing EQ centerpoints?):
Voice knob left of center...increasing scoop in the lower mids as you rotate counterclockwise.
Voice knob right of center...increasing peak in the upper mids as you rotate clockwise.
So you can sort of emulate a lower mid scooped Fendery tone, which ends up sounding cleaner and more polite, all other settings being equal...or an upper mids boosted gnarlier ruder dirtier sound rotated the other way.
The voice knob is before the drive stage, so rotating left cleans it up somewhat since there are less mids pushing it...and dirties it up somewhat to the right. There are a couple related sonic aspects shifting there as you adjust it.
The bass/mid/treble knobs are active boost/cut and occur after the drive stage; I think of them as finishing touches on a basic sound set up between the voice and gain controls...like controls on a mixer channel, shaping what a miked amp is delivering. That has worked well for me in recording direct.
Voice knob left of center...increasing scoop in the lower mids as you rotate counterclockwise.
Voice knob right of center...increasing peak in the upper mids as you rotate clockwise.
So you can sort of emulate a lower mid scooped Fendery tone, which ends up sounding cleaner and more polite, all other settings being equal...or an upper mids boosted gnarlier ruder dirtier sound rotated the other way.
The voice knob is before the drive stage, so rotating left cleans it up somewhat since there are less mids pushing it...and dirties it up somewhat to the right. There are a couple related sonic aspects shifting there as you adjust it.
The bass/mid/treble knobs are active boost/cut and occur after the drive stage; I think of them as finishing touches on a basic sound set up between the voice and gain controls...like controls on a mixer channel, shaping what a miked amp is delivering. That has worked well for me in recording direct.