Catalinbread TalismanPlate 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. 5x3 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