[Telegraphy] needed a reverb for his recording studio. There are hundreds of computer-based and standalone digital reverb systems out there, but he decided to build his own plate reverb. Reverb is an effect used in many professional audio and music recordings. Reverb adds thousands of echos to an audio signal. These echos decrease in amplitude over time. When used correctly, the effect is generally very pleasing to the ear.
A plate reverb uses a plate of sheet metal to generate the reverb. An audio driver is placed in contact with the metal plate. Audio is fed into the driver, which vibrates the plate. The vibrations travel along the surface of the plate, bouncing off the edges and reflecting back. These reflections are captured by a pickup, which then converts them to a voltage signal. The final reverb effect is actually created in the sound engineer’s mixing board when the “dry” source signal is mixed with the signal returned by the plate.
[Telegraphy's] plate reverb was built almost entirely from found, Radio Shack, and hardware store parts. The plate and frame are from Lowes. The audio driver is a cut up speaker from an old car stereo. The pickup is a modified piezo transducer from Radio Shack. As [Telegraphy] states several times, there are a lot of differing opinions on exactly how and where to mount the various parts of the reverb. Any placement will generate some reverb. The question is where and how to mount things for the best effect. Much like beauty and the eye of the beholder, the answer to that question is in the ear of the listener.
Jump past the break for a tour of a slightly more involved plate reverb at Gallery Acoustics Studio.