When using two CS-80 Filters (as in a real CS-80), ugly harmonics appear at higher frequencies.
To observe it, put in a row:
KBF > CS-80 osc (SQUARE) > cs-80 flt (HP) > cs-80 flt (LP) > Out
Play high keys, one after the other. Try in particular: G5, Bb6, Eb6
The issue is bound to the CS-80 filters. With a couple of Origin or Jupiter8 filters the result is much acceptable: the sound is cleaner (With two Jupiter 8 filters, unwanted harmonics appear only about A8). If you mix a CS-80 filter with one of an other kind, uggly harmonics come back.
Setting the HPF before the LPF reduces the problem a little bit.
I tried to tweak the TAE amount of the program just to see (or should I say, to hear) if it could reduce the unwanted harmonics. But the more TAE I add, the worst it is! The sound is best when TAE amount is set to 0.
In comparison, on the CS-80V2, switching on the low pass filter (left wide open) adds some noise. But that's very faint and as no harmonic stands out, this is no real problem.
So I have two questions:
1. (When) should we use TAE Amount?
2. Can we expect an improvement of the CS-80 filter's behaviour in high frequencies by the availability of the CS-80 template?