In trying to answer my own question regarding voice-spreading portamento on other synths, check out this link discussing the Oberheim OB-X analog polysynth:

http://www.retrosynth.com/~analoguediehard/studio/keyboards/oberheim_obx/index.html

If you skip down quite a bit (~2/3rds of the way), he talks about using the synth in Unison mode, which reveals the OB-X's imperfections in its polyphonic glide, which causes different glide rates for each voice. Hey! This is just like what I had discovered about the Mono/Poly! He is clearly in love with this sound, just like me.

Based on his text, though, it does not appear that the circuit for the OB-X was *purposely* designed to spread the voices -- it doesn't sound like Oberheim was purposely trying to have the glide rates be different, they just turned out that way. So, the purposely-detuned portamento in the Mono/Poly could still be a unique feature to itself.

What other synths have multi-voice glide Are the invidual glide rates purposely different from each other

Chip

--- In korg_mono-poly@yahoogroups.com , "chipaudette" <chipaudette@...> wrote:
>
> Hi All,
>
> I've been adding portamento to my Korg Polysix and, on my first try, I found it not very exciting...nothing at all like the great portamento on the Mono/Poly. So, I did some analysis of the Portamento on the Mono/Poly and found that it purposely spreads the pitches of the individual voices to make the sound more interesting and exciting.
>
> You may be interested in some of the details:
>
> http://synthhacker.blogspot.com/2013/04/portamento-voice-spreading-from-monopoly.html
>
> When I implemented this trick of the Mono/Poly in my Polysix, the portamento gained exactly the excitement that I was looking for. The designers of the Mono/Poly sure were smart!
>
> Is this voice spreading typical of old analog synths, or was it unique to the Mono/Poly
>
> Chip
>