I dug a little more into the Ensoniq chip found in ESQ-1's and Apple IIGS's.
Very cool chip!
Here's a link to Apple IIGS Docs.. specifically the Hardware Ref. Guide (Sound docs start at pg. 101)
http://www.classiccmp.org/cini/pdf/Apple/Apple%20IIgs%20Hardware%20Reference%20Guide.pdf and the Schematics.
http://www.classiccmp.org/cini/pdf/Apple/Apple%20IIgs%20schematic.pdf(Above file's root page)
http://www.classiccmp.org/cini/systems.htmSeems simple enough at the core. It uses wavetables you program. Volume is also controlled via bit values.
They show using 64K of RAM, but I think it's expandable.
It has support for sampling as well.
32 independent osc.'s total.
Up to 8 independent channels via an ext. demux to split osc.'s out. So 8 independent voices in all is possible, or 4 stereo channels.. whatever you prefer to do, I guess.
I'm sure with the right coding, you can split the keyboard/voices up for multitimbral applications.
Nice chip, but it'll be about $50 USD to buy an old Apple IIGS to scavenge the Ensoniq chip out of.. or cheaper if you're lucky.
But nice thing is that IIGS's are for sale all the time on theBay.
Even if it's not a good candidate to add/re-voice a Poly800, the programming methods are nice to study.. like I found it interesting that they mention there are no actual OSC's.. the OSC's are actually independent registers altered by the data.
The Apple Docs are just about the only published docs avail. for this chip since Ensoniq closely guarded their technology/software. But I know there are plenty of Ensoniq support sites out there to get even more info and perhaps code from.
Cheers,
-Blaine