But if there's no sound how do you know what it tastes likeThat’s the recommended approach for dialing the Mark amps (from the Mesa manuals): Start with tone controls at zero, bring up the treble to taste, then midrange, then bass.
But seriously I'm not sure you need to have zero sound with them all off for this method to work. Also, how I taste the treble will change when I bring in some mids and bass.