
Update via Chris Muir on AH:
"Actually the SMS polyphonic thing was closer to the original E-Mu Audity (not the Proteus in Audity clothing that EMu sold recently).
The SMS programmable polyphonic never saw the light of day, although it had a bunch of good ideas in it. The only thing that sort of spun off of that project was the SMS Voice 400.
I put scans of some of the SMS data sheets here."