Ensoniq ESQ-1 is a 61-key, velocity sensitive, eight-note polyphonic and multitimbral synthesizer released by Ensoniq in 1985. It was marketed as a "digital wave synthesizer" but was an early Music Workstation. Although its voice generation is typically subtractive in much the same fashion as most analog synthesizers that preceded it, its oscillators are neither voltage nor "digitally controlled", but true digital oscillators, provided by a custom Ensoniq wavetable chip. The signal path includes analog resonant low-pass filters and an analog amplifier. The synth also features a fully functional, if crude by modern standards, 8-track MIDI sequencer that can run either its internal sounds, external MIDI equipment, or both, with a capacity of 24,000 notes (expandable via cartridges). It provides quantization, step-editing, primitive forms of copy/paste editing, and can be synchronized with external MIDI or tape-in clock. ESQ-1 can store 40 presets internally, and features a cartridge slot for additional storage capability. ESQ-M, a rackmount version of the synthesizer, was released circa 1987, with the same specifications but without the sequencer. Notably, the sound chip at the core of the synth, the 5503 Digital Oscillator Chip (DOC), is a brainchild of Robert Yannes, father of the popular Commodore SID chip. Voicing The ESQ-1 features eight voices with three oscillators per voice, and is fully multi-timbral. Despite eight voice polyphony, it is capable of tracking nine voices - when using eight internal sounds in the sequencer, one additional internal or cartridge sound can be controlled independently. The wave ROM contains 32 different waveforms, including standard synthesis waveforms such as sawtooth and square, but also less usual ones such as "piano", "voice", or "bass" (note that, although multi-sampled, these are still single-cycle waveforms, not true samples as such). Each oscillator can be independently volume-controlled via its dedicated digitally-controlled amplifier, and modulated. Oscillator amplifiers provide room to be overdriven, and thus produce moderate analog distortion as an additional effect on, for example, synth leads or organ sounds. ESQ-1 has three independent LFOs, and three independent envelope generators which can be programmed to modulate any number of parameters. The fourth envelope generator is hardwired to the main output amplifier though it can still be used as a modulation source for other parameters as well. The output amplifier (DCA4) also provides programmable panning for each voice. Its envelope generators allow numerical level/rate settings, and like many other synthesis parameters, allow the use of negative values. Furthermore,