Ensoniq Concert Wavetable

ECW (Ensoniq Concert Wavetable) is a format that defines instruments for the Ensoniq AudioPCI sound card's MIDI software synthesizer. Unlike SF2, the ECW format is proprietary and not RIFF-based.

Links

 * https://en.wikipedia.org/wiki/Ensoniq_AudioPCI
 * Ensoniq .ECW File Format