Yes, I've got two of those old DSI pedals. They match nicely with the two Poly Evolver Keyboards. I'm color-coordinated.
I'm tweaking the high pass filter at several points as I play, but there is no white noise added at any point. As you know, that means it has to be set at least to "1" before you start playing, or else you'll get a loud "pop" when you first turn it. It's the quality of the digital waveform that, in lower registers and at certain cut off frequency points, has that "wispy" quality to it. I've come to identify this effect as part and parcel of the distinctive voice of the Evolver.
You know, this question constantly crosses my mind these days, as I debate whether or not to replace a PEK with a P12: "Can the Prophet 12 do that?" It's said that the Prophet 12 is the new Poly Evolver Keyboard, but I just don't hear it. To me, the P12 seems like a thoroughly different instrument, which is fine. The digital sounds I repeatedly hear P12 users making are quite different from those typical of the PEK, and I hear very little crossover. So, to repeat the nagging question - "Is it at all possible to create this sort of icy pad on the Prophet 12, wisps and all?"