An electromechanical substitute for an acoustic reverb chamber, where electronically generated reverb was unavailable, whereby a metal plate was suspended behind the sound source, fitted with a transducer and microphone pick-up. The plate was typically 4’ by 6’, suspended on springs within a sound-deadening case as a reverberant space. A vibrating transducer feeds the direct sound into the metal plate, and a pair of pick-ups extract the reverberation as vibrations bounce off the plate’s edges. A motorized damping plate parallel to the main plate can be remotely positioned at varying distances to control the duration of the reverb. The plate has a characteristic metallic, bright sound. Other substitutes were spring reverbs and slap echo devices.