Richard Atkinson

MOS Technology 6581 Sound Interface Device

The MOS Technology 6581 Sound Interface Device, found in the Commodore 64 home computer, is a very advanced sound chip for its time. I have long wanted to program this sound chip using an analogue synthesizer style interface, i.e. with one knob for every parameter. In 2013 I wrote some software to achieve this, using a Behringer BCR2000 MIDI control surface and a few Hard Software HardSID cards. This video explores the capabilities of the SID chip using this software.

MOS Technology 8580R5 Sound Interface Device

In 1986 Commodore released an updated, restyled version of the Commodore 64, called the Commodore 64C. The first version of this used the original MOS 6581 sound chip but a later version sold in 1987 (with graphics symbols on the top of the key caps instead of on the front) had a revised version of the SID chip called the 8580R5. This chip had significant changes from the 6581 design, so that in certain areas it has a quite different sound from the 6581. In this video I explore the sounds of the 8580R5.

Parameters on MIDI control surface

This image shows the SID chip parameters available on the MIDI control surface using my software. The group of six buttons on the left (two rows by three columns), not marked on the image, are Filter Voice 1, Filter Voice 2, Filter Voice 3, Voice 1 on / off, Voice 2 on / off and Voice 3 on / off.