Gear Geek: Yamaha DX7

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From the mid-''80s until at least the early ''90s, Yamaha''s DX7 was the synth that launched a thousand hits.

In the 1980s, the synthesizer with the greatest impact was Yamaha''s best-selling DX7. It radically altered popular music, heralding an age when electronic instruments saturated the airwaves and digital polysynths became the norm. Yamaha could barely keep up with demand at first, and analog synthesizers were soon considered passé. Demand for older synths dipped so low that you could snap them up for a fraction of their previous prices.

Launched the same year as the MIDI specification, the DX7 was one of the first synths that let you control one instrument by playing another. The DX7 relied on frequency modulation (FM) synthesis, a technique that Yamaha began licensing from Stanford University professor John Chowning in 1974. FM applies simple waveforms (modulators) to modulate the frequency of other waveforms (carriers), creating complex waveforms by generating sidebands. Instead of oscillators, the DX7 had six operators—sine-wave generators, each paired with its own envelope generator—arranged in 32 configurations called algorithms. The resulting sounds varied from pure tones to rich timbres that simulated acoustic instruments more realistically than previous synths. Keyboard velocity and aftertouch had enormous effect on dynamic spectra, making acoustic simulations more expressive than had ever been possible.

Although you could program the DX7 entirely from its front panel, the process was far from intuitive. The panel furnished an unlit LCD, a pair of sliders, and 42 membrane switches that made 168 parameters available. None of the familiar building blocks of subtractive synthesis were evident, not even a filter. Only a fraction of owners understood exactly how FM synthesis worked, and hardly any understood how to program their instruments beyond the basics. But the DX7''s challenging user interface didn''t hurt its popularity, and it became one of the first synths you could program on your computer using editor/librarian software.

With room for 32 internal patches and data cartridges each containing 64 more, the DX7 supplied a wealth of new and different sounds. It so authentically replicated the Fender Rhodes piano, and with greater flexibility, that sales figures for real Rhodes pianos plummeted. Synthesized mallet percussion instruments such as marimbas and vibes were suddenly in ample supply, and electronic orchestral strings gained a rosin-in-the-bow realism that wasn''t possible with analog synthesis. The DX7 was also one of the first synths that worked with an optional breath controller, making detailed brass and woodwind sounds all the more realistic.

The DX7 had limitations—it was monotimbral and had a monaural audio output—but future Yamaha synths such as the DX7II and TX802 improved on the original. Today, FM synthesizers have all but disappeared, replaced by the much more capable Native Instruments FM8 software and by even more realistic forms of digital synthesis.

Former senior editor Geary Yelton resides in Asheville, N.C.