The History of EMT and Reverbby Will Shanks Editors Note: This article was originally featured in a previous edition of our Webzine. We're running it again because of the ongoing relevance of the hardware units, and their availability as theEMT 250 Classic Electronic Reverberator, the updatedEMT 140 Plate Reverberatorand the newly introduced, money-savingEMT Classic Reverb Bundleat theUA Online Store.

There has always been a bit of controversy over reverbparticularly artificial reverb. Some purists still avoid it like the plague, while others embrace it as yet another creative tool in the audio engineer's palette. But let's backtrack to a time before digital devices, plates, and even chambers to the beginning of the controversy early in the history of audio recording...A Little Reverb History...In the beginning of electric recording around the mid-twenties, recorded reverb was essentially the audible byproduct of a physical distance between a sound source and a microphone. Record companies sought out appropriate rooms for a desired effect. Right from the outset of early recording, those early pioneers were already working with mic placement and rooms for a desired effect! But around the early to mid-thirties the jukebox was introduceda great invention, but the thirties were not yet a time for stellar playback systems, let alone recording equipment; and the early jukebox suffered from the early technology. But hey, they had to start somewhere! At the time, reverb from room ambience was practically banned from studios due to how it affected the performance of the jukeboxes. This is the primary reason most recordings from the mid-thirties until the fifties are, by design, "dry."As recording and playback equipment improved, so did the opportunities to experiment with new recording techniques, as well as new marketing ploys for playback resellers: Enter the "hi-fi" revolution of the post war era. It is commonly accepted that the use of reverb, whether natural room, chamber, or plate, practically defined the "hi-fi" era of music.An engineer named Bill Fine brought back the popularity of natural reverb as an effect by putting a single mic in a large hall to capture the ambience of a recording. The recording was released on Mercury's "Living Presence" record.

EMT 140 interior viewIt was UA's own Bill Putnam, Sr., who was the first to use artificial reverb creatively on a pop recording in 1947, with the use of the first reverb chamber (the studio bathroom!). The result was a huge hit by The Harmonicats called "Peg o' My Heart" on his own Universal label. Having the ability to control reverb amount and turn the effect on and off at will was a major breakthrough, and a big part of the record's sound. Bill went on to build dedicated chambers for his studio in Chicago, as well as his later LA studios. Chamber reverb is to this day a technological and architectural art all to itself. The sound he created captured the listening public's imagination, and artificial reverb was popularized as a production tool for the recording environment; but for most of the fifties, room recording and echo chambers were the only options.Enter EMTHowever, German company EMT (Elektromesstecknik) made a huge breakthrough in 1957 with the release of the EMT 140 Reverberation Unitthe first plate reverb. EMT was birthed from the Broadcast Technical institute in Nuremburg and the Institute for Broadcast Engineering in Hamburg. EMT in its day was by far the most popular developer and manufacturer of artificial reverb solutions for the recording industry. From the first prepackaged artificial plate reverb system, to the early (and arguably best sounding) EMT 250 digital reverb, EMT was the forerunner of the field.What's a Plate?And what are the defining sonic elements of a plate? I got to find out with my own ears during a visit to The Plant Studios in Sausalito, where they have multiple plate reverb units, including the ubiquitous EMT 140. It does not necessarily sound like a room, yet it has room-like qualities. The sound is dense, with heavy diffusion. The sound is wonderful, warm, open, and natural. Plates are still widely used in many studiosthe only drawback is the enormous size and weight of the devices. An EMT 140 weighs 600 pounds. Still, it's an easier alternative to the design and space concerns of a dedicated chamber, and I believe that was the idea, particularly in 1957.

Original EMT 140 Damper ControlInterior of the EMT 140The a plate reverb is made up of a large (2x3m), thin piece of sheet metal suspended from a steel frame by spring tensioners at each corner. An electrical transducer mounted to the center of the suspended plate induces plate movement, which creates the effect. One or two (mono or stereo) pickups are mounted to the plate as well, for the reverb return. A damping plate controlled by a servo motor, allowed adjustment of the reverb time. All of these simple elements were built into a heavy wooden enclosure.Typically the engineer sets his decay with the damper control, and runs the reverb return through additional EQ at the board for greater tone shaping capabilities.The 140s are generally the favorite plate of the audio community, but many fans of the plates were not crazy about the original electronics, and a lot of the units were later retrofitted with updated electronic components. In 1961, EMT hit another first by adding a stereo return--by the seventies, the EMT plates were manufactured as solid-state. Further improvements were made to the technology, and EMT made many other plate systems and models, but the 140 is still considered the de-facto system for the best in plate reverb.EMT Goes DigitalEMT released a primitive digital reverb in 1972, the rack mount 144, but its capabilities were limited, and very few survive. But in 1976, EMT teamed up with American electronics company Dynatron to create the EMT 250 Electronic Reverberator Unit-and the first "practical" digital reverb was born.It was a floor-standing unit, and looked like equipment from a seventies sci-fi movie set (shades of things to come withStar Wars?). The feature set was impressive, with pre-delay controls and high and low frequency decay times. But the 250 was more than a reverb; it was the really first multi-effects unit that us youngsters can so easily taken for granted these days. Modulation effects like chorus and phase were available, as well as echo and delay. The controls were simple, large lollipop-shaped levers and a few pushbuttons.

Controls of the EMT 250 hardwareThe EMT 250 Electronic Reverberator UnitThere were only 250 EMT 250's made, but the unit was soon updated to the 251, which was a similar design with an LCD display and a larger feature set. The 251 offered extended frequency response, additional parameter controls and more programs. These early digital units are considered some of the best sounding artificial reverb units ever made-quite a legacy for anything considered early digital technology. Both units easily fetch over $10,000 on the used market.Special thanks and resource credit to Dan Alexander, Dave Kulka, Bob Buontempo, and John Cuniberti

The EMT 250 Electronic Reverberator by Will Shanks

I recently spent some time atAllen Sides Ocean Way Recordingin Hollywood. During Allens enlightening tour of those hallowed Putnam-designed rooms and echo chambers (Ocean Way was of course previously United Recording, created by M.T. Bill Putnam), I noticed the extremely rareEMT 250reverb units in three of the four studios. The EMT 250s industrial design is unmistakable; it could easily pass for scrap equipment sold by the Jawas in Star Wars. After commenting to Sides about the relative abundance of 250s in his control rooms, he told me he considers the EMT 250 to be one of the finest-sounding reverbs ever made. This is no mean feat for a product created in 1976, especially considering the EMT 250 was actually the first digital reverb ever made.Some might consider an EMT 250 a third-string choice for someone like Sides, who has Putnam echo chambers and EMT 140 plate reverbs at his disposal, but the EMT 250 has a sound all its own and is actually his first choice for a myriad of applications. (Sides confessed to owning eight of them at one point!) While I was there, Studio A was unoccupied, and I got a chance to listen to the unit. This made me want to learn a little more.

EMT 250 Origin and DesignAlthough digital audio technology had been used since the early '70s for things like simple delay lines, the professional audio world was still heavily entrenched in all things analog when German company EMT offered the first digital reverberation system. After that, things began to change very quickly, particularly in the market of artificial reverberation. Lexicon, AMS, and others soon followed with their own offerings.The EMT 250 was introduced by EMT Technical Director Karl Otto Bder in 1976 at the Zrich AES Convention. Designed to be an alternative to theEMT 140plate reverb systems that were enormous by comparison and required strict isolation to avoid sympathetic resonances, the EMT 250 offered a new sound in a relatively compact, easy-to-use package. The digital hardware portion of the EMT 250 project was farmed out to Ralph Zaorski through a Massachusetts electronics company by the name of Dynatron. MIT professorBarry Blesserwas hired to perform the algorithm design. Karl-Otto Bder was then instrumental in moving the project from the research phase into the product phase, and also performed the listening and voicing for the EMT 250.EMT built the converters, analog sections, and power supply for the unit. They also provided theclearlyGerman industrial design, with its semi-portable rolling chassis, illuminated pushbuttons, and sci-fi control levers. But of course the magic was in the algorithms themselves, and Dr. Blessers passion for acoustics andprevious experience with digital audio technologymade him the ideal candidate to tackle the daunting task of creating a convincing set of ambient cues via a digital circuit.Its 400 ICs and 16k of memory in this mono-in, quad-out unit (yes, four discrete outputs) required three fans, plus enormous heat sinks covering the entire cabinet exterior. In an interview with theMix Foundationin 2007, when theEMT 250 won the TECnology Hall of Fame Award, Blesser recalled, "We put the power supply on the outside and painted it red. We took all the problems and turned them into unique signature symbols." During a recent conversation with Barry Blesser, highly regarded EMT 250 serviceman David Kulka said, Designing the very first professional digital reverb in the early '70s, with the limited technology then available, must have been a tremendous challenge. Especially emulating the three-dimensional properties that make a room sound like a "room" as opposed to, let's say, a plate. It is really amazing that over 30 years later, the EMT 250, with hundreds of discrete logic ICs, no microprocessor, and minimal RAM, is still considered one of the best-sounding reverbs that money can buy.

How does it sound?On my first listen to the reverb unmixed with the source, it sounded unmistakably digital, a touch noisy, and even a little aliased and lumpy, especially at long decay times. But there was some indefinable magic to it. I then heard the source mixed back in, and the sound suddenly jumped to life. After much listening, my perception was that the 250 naturally blended with the many sources we tried even better than the plate reverb. It had an amazing short decay response, better than any other reverb I can recall. I was hooked! Now if only there was a unit for sale somewhere and $10,000 in my bank account. As with so many audio tools considered classics, the perfection was seemingly in the imperfections with the EMT 250.As with so many audio tools considered classics, the perfection was seemingly in theimperfections with the EMT 250.The EMT 250 is obviously most famous as a reverb, but in reality is more than that. It is the first multi-effects unit. I was able to spend some time listening to the other programs and was particularly impressed by the complex Chorus program and the Phaser, which interestingly has no LFO and must be phased by hand with the units white lever. I could definitely imagine using it on a song break or intro.How does it work?Finally, I got my hands on the controls andI must confessthe tactile experience was nearly as pleasing as the sound. The click-stop levers with visual reinforcement via the LED ladders combined with the Set button was satisfying and more importantly, intuitive. When using the Reverb program, the red left-side LED ladders indicate the user is controlling Decay and LF/HF filtering, while Predelay uses a green LED ladder. When another program is selected such as Delay, all LED ladders shift to green and indicate delay time and output routing. You get the idea.

Since Chorus provides a different result from each output, combining different physical outputs from the unit can create different sounds. This added another layer of complication to the setup because it was best served when each output had its own fader on the desk. The result was worth it though, as the sound was very pleasing, especially on acoustic guitar and electric bass. Similarly, the Reverb and Phaser gave variations on sound when auditioning the additional outputs of the EMT 250. I actually preferred the rear outputs from the Phaser versus the front outputs.A Few Sentences MoreThe EMT 250 carried a $20,000 price at its debut in 1976, and only an estimated 250 units were ever built. If you happen to stumble on one at a yard sale, I highly recommend sending your unit toStudio Electronicsin Burbank, California for a full service. Mr. Kulka is the only man in the hemisphere who truly specializes in these magic boxes, and he even carries a stockpile of parts.While they no longer make hardware reverb products,EMTstill in business and is selling recreations of a few of their most famous hi-fi phono cartridges and tone arms, along with other professional audio, broadcast, and television products.Special thanks to Allen Sides and Ernie Woody for their hospitality at Ocean Way, David Kulka of Studio Electronics for letting me pillage some of his comments from Gearslutz, Hillel from the Mix Foundation for quotes and information from his EMT 250 TEC Hall of Fame page, Jules Limon of EMT Studiotechnik GmbH for additional information about EMT, and Support Report own Dan Becker for the cool-as-hell Photoshop work!