Bug or limit of DSP programming? Weird LFO > Cutoff Frequency modulation

MaF · 12. Juni 2013

Can you reproduce the error at the end?

Start with an init preset
Turn OSC Balance all to the left
At the LFO page in Virus Control turn the amount by which LFO 2 modulates Filter 1 all to the positive top
Now increase LFO 2 rate bit by bit, press C1 and hear how the modulation accelerates
Stop at 125 and press C1

Not only is the filter modulation rate at this setting a lot slower than, let's say at 121. Moreover, I get different speeds each time I press C1. Actually it starts to sound weird after 118 or so.

Is this a bug or the limit of DSP programming?
Let me tell you, I tried exactly this because I was curious if it works. In an interview with the German online magazine Amazona Christoph Kemper praised the audio rate modulation of the filter in his code and I was not convinced. I thought, digital solutions might be fine for moderate emulations but when it comes to extreme settings like audio rate modulation software has to pass. Recursive modulation anyone?

Just curious
MaF

guitarie · 12. Juni 2013

Hi MaF,

I can only tell you that what you describe, that happens to me too .....
no idea how this happens?

cheers

flabberbob · 13. Juni 2013

In TIOS4.5.3 I did notice some variation in the underlying pulses of the sound texture, but overall it was the same sound. The variation stopped once I set TRG PHASE to a value other than zero. Another thing to note is that when the modulation amount is at the extremes, any initial filter cutoff value other than 64 will get the LFO shape chopped off (i.e. saturated).

MaF · 17. Juni 2013

So is this a bug reproducable at access? Maybe Marc can chime in?

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