rotary speaker

A rotary speaker is a speaker cabinet design whose moving sound is emulated by many guitar effects, most directly by pedals designed to reproduce a Leslie rotary speaker cabinet¹. In a rig, the term appears most often as a sound description: modulation effects such as phasers, choruses, vibratos, and delays are said to reach rotary speaker-like sounds, shimmer, warble, or swirl at certain settings²³⁴. Sources describe these tones as swirling, liquid, or bubbling, and associate them with recordings and sounds made famous in the 1960s and 1970s⁵⁶. Dedicated controls such as Depth and Rate, or an expression pedal controlling rate, can set the effect⁷.