1970's ECHO PLATE
They should have called it a Stereo Reverb Plate. It is a large reverb device manufactured in Austria from the mid 1950's to the late 1970's. It produces just one sound and has an adjustable decay time however it produces a superior reverb. It is a large device which needs isolation so it is not really suitable for a home studio unless you live in a large property.
EMT 140 plates are highly valued by professional engineers. A few years ago we sold 4 EMT plates to a client in New York, they originally came from Olympic Studios , the cost of packing and air freight alone would have bought a couple Lexicon 960L units that is before you add on the price of the EMT's. 10 years ago we bought 2 EMT 140s from a customer who bought them from the John Lennon estate and had been used in John Lennon's Ascot Studios.
The EMT 140 echo plate was the standard reverb unit used in most professional recording studios and broadcast establishments since the 1950's Malcolm Toft told me that when he worked as an engineer at Trident studios they had a couple of EMT plates, some Audio & Design compressors and very little else for processing plus a stereo tape machine for delays bu they managed to make some fantastic recordings there.
They are large units, over 2 meters long, they are heavy & need to be isolated from loud sounds and they only have one sound yet despite the efforts of many software designers working in various recording effects manufacturing companies it cannot be beaten for sound.
In its simplest description an EMT 140 consists of a mild steel plate connected to a metal frame and kept under tension, there is a driver in the centre which is connected to the plate ( imagine a loudspeaker with its paper cone removed ) also there is a pick up at each end, there is also a damping panel the same size as the plate which can be moved nearer the plate to shorten the decay time or moved away from the plate to lengthen the decay time, this all goes to provide a mono in stereo out superb reverb effects unit adjustable from 0.5 second to 5 seconds.
It sounds so simple which makes one wonder why studios do not make their own, there is nothing to stop this as the patent expired in the 1970's. Many have tried and many failed, in conjunction with bel electronics we made a couple in the 1970's and they sounded awful. Apparently the engineers at EMT used to visit a steel foundry in Wales to select the steel sheets, apparently it is the unique quality of steel which provides the superb sound, unfortunately the foundry which produced the steel has long been shut down so the steel plate is no longer available.
This one comes with a motor to allow the decay time to be adjusted using the controls on the electronics panel, this can be remoted, some remotes have a meter showing the decay time, or you can use your ears.
Confused ? Take a look at this You Tube Video, if you visit YouTube there are other videos about EMT Plates