MOS Technologies SID

The MOS Technologies 6581/8580 SID (Sound Interface Device) was the built-in sound chip of Commodore's CBM-II, Commodore 64 and Commodore 128 computers. It was one of the last sound chips to be made for any home computer prior to the digital sound revolution.

The SID was created by engineer Robert Yannes, who later founded the Ensoniq digital synthesizer company. Together with the VIC-II chip, the SID was instrumental in making the Commodore 64 the best-selling computer in history, and is partly credited for initiating the demo scene.

Table of contents

1 Modern developments
2 Features
3 Notes
4 External links

Modern developments

In the late 1990s, an electronic musical instrument utilizing the SID chip as its synthesis engine was released. It is called the Sidstation and is produced by Swedish company Elektron. Since the SID chip had not been manufactured for years, Elektron allegedly bought up almost all the remaining stocks of the chip.

Also in the 1990s, a sound card for IBM PC compatibles called HardSID was released. The card contains one or two SID chips and allows a PC to utilize the sound capabilities of the chip directly instead of by emulation via e.g. SoundBlaster.

Features

three separately programmable independent voices (up to 8200 Hz)
four mixable waveforms per voice
three mixable filters
attack/decay/sustain/release (ADSR) control
two ring modulators
two 8-bit A/D converters
external input (for sound mixing with external signal sources)

Notes

A .SID file, known colloquially as a "SID", is a sound data file (akin to NSF) typically copied directly from the SID chip music/sound of a Commodore 64 game or demo.