diy GM synth

[The Dark force of dance]

Y-ellow Y'all.
	I've had the Crystal semi data books for years. Actually there's some very
nice articles about S/PDIF and AES/EBU protocols in there. Crystal were
once renowned makers of digital audio conversion products. Though these
days they're all pretty good.

I actually run one of their test bench sound cards in the computer I use
over my work bench. They made a series of sound cards, including ones using
this particular chip-set, as evaluation boards. I have to say, the one I've
got is pretty crap.

There are three chips in crystal's GM range. One is an FX chip which can be
used as a limited GM engine. More often it is used as an outboard FX
processor for the bigger of the two GM engines. I had been looking at them
for a long time but not seriously as they are too limited. If memory
serves, they can't refresh a DRAM so they can't be uses as an actual
sampler. They have no filters on the interpolator/multiplexor so they're
not really worth the _Huge_ money I'd have to pay for 'em here.

It would likely be cheaper to buy the eval board direct from crystal. The
board I got cost me $35 bux. That was at a time when sound cards cost
around $100. (Here in this neck of the woods at least)

I'm led to believe that there is a chipset from Hiundai or someone, which
is pretty mind boggling. I've never been able to track this down but
someone might know. I'm told it has multi-mode filters and supports 32 meg
of RAM direct. You still need to control it with a micro but an MCS51 is
usually all that's needed. An extraordinary number of Music/sound related
products use MCS51 simply because they're extraordinarily good at doing
MIDI stuff.

Out of interest. Crystal also make a range of S/PDIF-AES/EBU transceiver
chips. These would be of extreme usefulness should they be obtainable
cheaply. Because all sound cards, and nearly all digital sound producing
devices use the I2S (IC Interstage Sound) architecture these days, It would
be no great stretch to add S/PDIF outputs (at least) to any sound card that
didn't provide them. Since it is (in theory at least) simply a matter of
piggy-backing the transmitter chip on the I2S bus leading out to the
on-board D-A converters.

The only advantage with using the crystal chipset is that you know what I2S
mode they're running in straight up.

Oh! Yeah. Another way round this if your hacking your own Digital audio
cards. Get hold of an old GUS card. The GF1 chip. (If memory servers to
render it's designation) was originally made by and for Ensoniques and
Apple. It first appeared in the Apple ][ GS. I forget what Ensoniques
product used them. There use to be a wealth of information on the net about
hacking GUS cards. Including adding Crystal converters and transceivers etc. 

Now. If anyone's got any serious information about getting under the hood
of an AWE32 card?..... :)

Be absolutely Icebox.

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