(2) Video Game Sound + Speech ( was RE: 80's Video...)
jdm at synthcom.com
Thu Feb 29 07:42:19 CET 1996
On Wed, 28 Feb 1996, Clive Jones wrote:
> Bally first used the custom 3 channel analogue IC - "AY-3-8910", I've
> just checked the chip itself and and no manufacture ID is given except
> for the two *large* letters "G.I.", Bally went on to use another "G.I."
> chip - the "AY-3-8912"
I have an AY-3-8910 - it's a General Instruments part. IMO it's not very
useful for synth-diyers. The AY-3-8912 is a little more flexible and
_perhaps_ useful. I seem to remember a cool looping envelope feature...
> Williams "Defender" series electronics used the 55564 CVSD speech chips,
> which, I believe are loaded in serial format rather than parallel.
I'm pretty sure the 55564 was a Harris part. CVSD was a fairly cheap way
to compress speech, encoding changes in the slope of the signal as a 0 or
1 in a serial bit stream, depending on whether things were going positive
or negative. Low bandwidth - maybe 40-4000Hz, and kinda grungey (and not
a charming sort of distortion like LPC). Maybe there are ways of messing
w/ the digital data that would be cool, but like I said, it's grungey.
Sherman, set the Wayback Machine for 1984, when I designed & built an
Apple II board w/ 4 phone line interfaces, 4 channels of CVSD output, and
4 DTMF encoders/decoders. If I had marketed it as a telemarketing tool,
I'd be rich. As it is, it's been used to run a Gay Phone Dating Service
for 24 hours a day, 7 days a week, for 11 years.
Ob DIY: I used machine tool sockets in perf board w/ wire-wrap wire
soldered point to point to construct the board, and it's been totally
reliable since I tracked down a cold solder joint that started causing
problems after 4 months. A useful construction technique if you don't
want to layout a pcb...
More information about the Synth-diy