As Larry Crane, editor of Tape Op magazine, noted, “Plate Reverb. Many people ask me about this and I usually tell them to listen to some records from the ‘70s and ‘80s and look for reverb with a thick, pillowy sound that doesn’t obscure the vocal yet doesn’t quite sound like an actual room.”
In 1983, I was the owner of a 16-track studio. One of the things that really separated the sounds of the recordings we could get from the sounds of the recordings made in major facilities was the quality of the reverb.
Spring reverb was the only affordable system for small studios at that time, since EMT plate reverbs ran almost $9,000!
EMT’s patent was about to expire, and when it did, competitors came out with similar products. While they were cheaper, they still averaged $2,500!
So an engineer who worked with me, Joe Errico, and I researched plate reverbs and came up with an affordable way to build one.
This article presents our plans for making a plate reverb unit, which won’t require any electronics other than your mixer and a headphone amp. (If you don’t have these items, you’re not ready for a reverb plate anyway.)
The construction cost will be between $100 and $500, depending upon what components you already own - a lot less than the $2,500-$8,500 for commercially available units.
Later in the article, I’ll also detail how to find and evaluate the materials needed, construct the frame, mount and tune the plate, fit the driver and pickups, and add dampening to the plate.
It concludes with some “tricks” and techniques for enhancing plate sound.
Almost everyone with a knowledge of recording is familiar with spring reverbs, or at least with their sound. (They were the most common type reverbs used in studios when this article was originally written. Now digital reverberation units are the type most often used.)
Most low-end or semi-pro reverb units were based on the spring principle, as are most musical instrument amps or accessories with reverb. That “spring sound” can range from excellent to “under water,” depending on the unit and the way it is used.
Figure 1: The finished reverberation plate. (click to enlarge)
The reason spring units sound the way they do is because that is exactly what they are; springs. There are usually several rows of them, possibly with two or three strung in a series. Just like the springs on your screen door, they will “twang” or “boing” when plucked.
However, instead of being plucked, the reverb springs are excited at one end by a driver and mic’d at the other end by a pickup - and so are the twang and boing, especially on transient material.
Although some designers have used tricks to smooth out their sound with excellent results, they may still have spring characteristics inherent in their sound, as well as a limited bandwidth, especially at high frequencies (8 kHz+).
Plate reverb has none of these drawbacks, although it can go from sounding like a true concert hall to an oil drum being banged with an ax in the subway, again depending on its application and who’s using it.
Typically, the plate is a large (one by two meters, or 39.37 by 78.74 inches) sheet of steel suspended in a tubular steel frame.