Cherry Audio Forums

My best attempt to describe this technically would be; If the filter is wide open, with low pass and global resonance maxed, there's a weird pulse of the oscillator's fundamental frequency as the envelope moves from the attack to decay portion of the envelope (set A and D to longest for a clear listen, though a short decay also gives a "thump"). This can be heard with less extreme settings, but this makes it clearest.

To be slightly less scientific; it kind of feels as if the frequency of the filter can wander way higher when you combine the LPF + AL + brilliance, and as the filter goes supersonic it's causing weirdness.

Sadly I don't have a CS-80 to test if this is expected behaviour!

I tried to duplicate the settings you described, but you neglected to say what the IL and AL settings were. I do hear what you might be referring to as a "thump", but this occurs when the filter cutoff matches the oscillator frequency. This is totally expected because the filter has a gain of about 12db at this frequency when the resonance is maxed. If you don't think that that is the proper explanation, please provide more details.

Thanks,
--mb

I looked into this a little further with a spectrum analyzer and it has now been revealed to me that the thump you are hearing is the highpass filter rising up to meet and amplify the fundamental. Since the global BRILL paddle raises the resonance on both filters, this is what's going to happen.

--mb

Full filter sections left to right, at the extreme end of each slider, starting from HPF frequency:
Down, down, up, up, up, up, up, up, up, up

It sounds like the synth is saying "WINNNINGG" every note.

I think you're right about HPF resonance being the cause, and I was wrong about the fundamental being the issue, it's the harmonics ducking out of the way that is causing this sound. Once you hear it, the 'WINNING" sound even occurs with the filter sections resonances set to 0 and global resonance set "flat" in the middle.

The behaviour of the filters/envelopes is completely different on the competition v4, so I'm willing to accept that this product just isn't the one for me, I just really wanted to love this synth.

I'm very sorry you're allowing such a weird edge case, something you would never dial up in any actual situation, stop you from enjoying the GX-80. You probably would not enjoy an actual hardware CS-80 either because it does the same thing. If the competition's product doesn't do it, I guess they got something wrong. However, you should use whatever you enjoy most. Good luck with your music.