Plate reverb is an artificial effect that utilizes a sheet of metal that vibrates sympathetically with a soundwave that hits it. The basic architecture of a plate reverb unit has a large, thin sheet of metal (nearly 6.5’x3’ in the case of the legendary EMT140) that has a transducer at one corner driving the sheet in much the same way as a speaker would, on the other end a pickup to capture the vibrations of the metal sheet, and a mechanical dampener that reduces the plate vibration.

The reverb sonically stays out of the way of the dry path due to the minimal initial reflections and a full warm reverb that tapers smoothly fades out into a tail. In the studio, plate reverbs were routinely employed due to the way they added a natural ambience without interfering with the original program material… That and the fact that even though they were nearly 7 feet long and 4 feet tall, plate reverb units were a heck of a lot smaller than a giant room or hall when ambience was needed on recordings.