IK Multimedia CSR Plate ReverbPlate reverberation first came out in the late 50's when an electromechanical transducer similar to a common speaker voice coil was coupled to a long metal foil (a plate) and a piezo pickup was wired at the other end. Running signal through the speaker would cause the metal plate to reverberate and the resulting sound picked up by the piezo transducer would be converted into electrical signal sent back to a mixing console to be mixed with the original