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The creator of the SID chip, the versatile soundchip found in the Commodore 64.

Bob Yannes was a young engineer, working at MOS Technology, a daughter company of Commodore.
There he had been responsible for the design behind the VIC-20.
In spring of 1981 he was given the task of developing a soundchip for the Commodore 64 in the shortest possible time. "MOS 6581 Sound Interface Device" - the SID-chip - was a very well-constructed soundchip for its time. Because of its hectic phase of development, full documentation of the chip's possibilities was never finalized: the first one was written for the prototype and it changed so many times that it didn't make sense at all anymore. Nonetheless, the SID's possibilities were soon recognised, mainly by the game producers who assured the huge success of the Commodore 64. Until then there had not been a soundchip of that calibre in a homecomputer.

"I had worked with synthesizers and I wanted a chip like those in a synthesizer", he stated.

According to Yannes noone in the project team knew how to carry out the project.

"Apart from the basic research, that I'd been doing since highschool, the actual development of the SID took just 4-5 months."

Yannes high expectations on the SID was the reason why the chip got unusually high quality compared to those found in videogames.

Quotes taken from an interview in Swedish magazine "DatorMagazin" from 1987.


Here are some excerpts from an interview I conducted with Bob Yannes in August of 1996:

Q: Did you foresee that people would actually treat your little VLSI-chip like an instrument?

A: Actually, I was an electronic music hobbyist before I started working for MOS Technology (one of Commodore's chip divisions at the time) and before I knew anything at all about VLSI chip design. One of the reasons I was hired was my knowledge of music synthesis was deemed valuable for future MOS/Commodore products. When I designed the SID chip, I was attempting to create a single-chip synthesizer voice which hopefully would find it's way into polyphonic/polytimbral synthesizers.

Q: The SID is very complex for its time. Why didn't you settle with an easier design?

A: I thought the sound chips on the market (including those in the Atari computers) were primitive and obviously had been designed by people who knew nothing about music.

Q: Did Commodore ever plan to build an improved successor to the SID?

A: I don't know. After I left I don't think there was anyone there who knew enough about music synthesis to do much more than improve the yield of the SID chip. I would have liked to have improved the SID chip before we had to release to production, but I doubt it would have made any difference to the success of the Commodore 64.


Bob Yannes left Commodore/MOS in the mid-1980s and co-founded the successful synthesizer company Ensoniq.

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