Fender Tone Master FR-10 and FR-12

[nevershouldhavesoldit]

I’m pretty confused as to why a “flat response” unit has tone controls.

I assume that the EQ is to maintain flat response regardless of room acoustics. The full range flat response measurements are made in anechoic spaces with no resonances. But no speaker / cab combo will have the same frequency response regardless of room, so EQ is needed to flatten it.

Of course, there’s no way to easily dial in a flat response, especially with no way to measure it and only 3 bands with fixed ranges and Q to adjust it. You’d need a calibrated reference mic system and real time display to know the response and a multiband parametric equalizer for adjustment.

FRFR powered speakers are really just wider range systems with flatter response curves than guitar amps. Those curves are correctly called curves because none is truly flat.