Lexicon Model 1200
A box that could stretch or squeeze time itself — and won an Emmy doing it.
Overview
The Lexicon Model 1200 is an Audio Time Compressor and Expander, a digital processor built for broadcasters who needed to fit a program into a slot without the program sounding like it had been sped up. The pitch stays put while the running time moves. That is the whole trick, and in the early 1980s it was enough to earn Lexicon an engineering Emmy from the National Academy of Television Arts and Sciences, which cited the company specifically for developing the 1200.
The pitch stays put while the running time moves.
The practical problem the 1200 solved was money and schedule. Making commercials fit precise time slots, as period advertising put it, used to mean retakes and editing — costly, slow, and destructive to a good take. The 1200 let an engineer compress recorded material by up to 25 percent or expand it by up to 10 percent while retaining full 15 kHz bandwidth, per Studio Sound (May 1983, p.15). The same notice describes speeding up or slowing down program material without changing pitch, "broadcast-quality audio free from distortion." A keypad lets the operator enter the original running time and the desired percentage of compression or expansion, and the unit also controls a variable-speed tape recorder.
How it works is the interesting part, and Lexicon's own technical notes lay it out. The 1200 performs what the documentation calls "intelligent splicing," sampling the audio at a very high rate and removing the redundant properties of vocal sounds. Inside sits a Z-80 computer backing up an integral high-speed pitch processor. That pitch shifter is linear in the frequency domain: if two pitches were an octave apart in the original, they stay an octave apart after processing, because every frequency is multiplied by the same constant. The actual shifting happens by storing information at one rate and retrieving it at another — the pitch-shift ratio is simply the ratio between record speed and playback speed.
DB Magazine (April 1981, p.21) framed the 1200 as a way to eliminate time-consuming retakes, letting an operator push a button and get "time-tailored" programming that preserves original pitch and voice quality. The unit connects to virtually any variable-speed tape recorder or variable-speed projector and/or videotape recorder, which is what made it useful across film, video, and radio production rather than being locked to one medium.
A second-generation version followed. Recording Engineer (April 1981, p.123) published the Model 1200's front-panel layout, showing its tachometer, actual play time, pitch shift ratio, and speed factor readouts alongside the invert control. The same notice states that all the new features were standard and available as upgrades to existing Model 1200 units — a detail collectors should note, since an upgraded early unit and a later-production unit may be functionally closer than their serial numbers suggest.
There was also a wideband sibling, the Model 1200B, which did everything the 1200 did with the added feature of wideband (15 kHz) operation to meet network TV and AM radio broadcasting standards. Lexicon's advertising from the period pitched the pair together: the 1200 for standard broadcast work, the 1200B for operations that needed the wider band. The 1200B is a distinct model and should not be confused with a 1200 that happens to have been upgraded.
For collectors, the 1200 occupies an odd and appealing corner. It is not a reverb, not a delay, not a synth — it is a utility processor from the moment digital audio started doing things analog tape simply could not. The Emmy recognition, the Z-80 inside, the intelligent-splicing approach to time compression: all of it dates the unit precisely to the turn of the 1980s, when broadcast facilities were beginning to trust digital processing in the signal chain. Units surface occasionally, usually from station liquidations, and the practical questions are whether the pitch processor and the Z-80 support circuitry are healthy and whether the unit has received the second-generation upgrade. Documentation and application notes are worth chasing down, because the 1200 was sold as much on its application flexibility as on its spec sheet.
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