EMT 140 (1957)
The first artificial reverb unit, a massive electromechanical plate system introduced in 1957.
Overview
The EMT 140 is the world's first plate reverb unit, introduced in 1957 by German manufacturer EMT (Elektro-Mess-Technik). It revolutionized studio recording by providing a compact, controllable alternative to echo chambers and spring reverbs. The unit uses an electromechanical transducer to vibrate a large metal plate, capturing the resulting sound with pickups to create lush, smooth reverb. It was swiftly adopted in professional studios and remained in use for decades. A remote-controlled version exists, allowing on/off switching via relay, and later models incorporated updated electronics like the EMT 162 with higher input impedance.
Specifications
| Product type | A reverberation plate ("Reverberation Plate EMT 140") |
| Manufacturer | EMT (Elektromesstecknik), Elektro-Mess-Technik |
| Country of design/manufacture | German design and manufacture |
| Production years | Introduced in 1957 |
| Dimensions | 2.4 meters (8 feet) long by 1.2 meters (4 feet) high |
| Weight | 270 kilograms (600 lbs) |
| Output level | -3 dB (.55 V) into 600 ohms at 1 kHz |
| Input impedance | 5k ohm (with EMT 162 electronics) |
| Input/Output Impedance | May vary between models |
| Model variants | EMT 140 TS, EMT 140 FB-TS, EMT 140 Solid State Stereo Plate |
Design
The EMT 140 uses an electromechanical transducer, similar to a loudspeaker driver, to generate vibrations in a large sheet metal plate. Early units featured a drive coil wound over a heavy brass core, later replaced with a lightweight aluminum core to improve frequency response. The system supports remote operation, with some versions including relay-based on/off switching via external control. A block schematic exists for the stereo EMT 140 TS model, confirming its operational topology.
Context
Introduced in 1957, the EMT 140 was the first artificial reverb unit available to studios, offering "reverb on tap" and replacing the need for dedicated echo chambers. It provided a smoother alternative to spring reverb and became a studio standard. The unit's 600-pound mass made it a logistical challenge, but its sonic quality and space efficiency compared to echo rooms made it highly desirable. It marked a breakthrough in audio engineering and established EMT as a leader in professional reverb technology.
Market
A 1960s EMT 140 was listed with a new price of $2,257.97, while stereo versions from the same era have been priced as high as $11,430. A mid-90s used unit was listed at $7,800. John Lennon's EMT 140, used during the recording of "Imagine," was auctioned by Bonhams in December 2023. Original manuals and sales brochures have sold for $160.
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