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Using a custom control to sweep LPF cutoff


#1

Please put me out of my misery…

I’ve been trying to set up a custom control (linear) to control the cutoff frequency of a LPF and I’m having no luck getting a full range sweep going. There must be a simple thing I’m not doing. Is the v/oct custom control a better option? (which I also tried with no luck). I’ve tried offsets, rectifiers, etc…

Any help would be great!


#2

Please state firmware version. :wink:


#3

Sorry Brian. 0.3. Haven’t updated to 0.4 yet due to a gig this Monday.


#4

Sorry for the late reply. I am now finally back in front of my modular.

(v0.3-only answer)

So both the Pitch (V/oct) custom control and the Linear custom control should be able to give you a full sweep of the LPF frequency.

Here is how I would set it up:

To sweep the frequency linearly:

  • Assign a linear custom control
  • Set the modulation gain to at least 1000x. The linear control goes from -5 to 5 so this gives you a sweep of -5kHz to 5kHz. If you want a wider range then you can set the modulation gain even higher.
  • Set the modulation bias to taste. Here I am using about 2.5kHz.

0013

To sweep the frequency exponentially there are no gains to set:

  • Assign a pitch custom control
  • Set the modulation bias (tune) to taste.

0014

For completeness, at the Custom Unit, level my example looks like this:
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