Rotary Speakers

The other half of a tonewheel organ sound. A rotary speaker spins a treble horn and a bass drum at two speeds, and the Doppler shimmer, the ramp between chorale and tremolo, is as much the instrument as the drawbars are. Compare the type first (a real rotating cabinet, a stationary cabinet or a pedal that models one), then the amplifier power, what it plugs into and how you switch speeds.