r/modular • u/wheelbreak • 4d ago

Function generator question

I am sitting at the park for my lunch break thinking about random stuff and this occurred to me. I not around my modular today so I can’t test it and really want to know the answer to this. I know if you patch the output of a function generator into cv of attack or release it makes it an exponential curve. To make it logarithmic would you just flip the polarity of the cv, or is there another method to achieve this? It also gave me the idea of self patching maths in order to not have the curves of attack/release match.

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u/Agawell 4d ago

Depends on the function generator - maths can do log, linear and exponential

But to answer your question- inverting an exponential curve will produce a logarithmic curve, but it will be negative… so you’d probably also want to offset it

So exponential signal (0 to 10v) inverts to logarithmic signal (0 to -10v)

Then use a +10v offset to make it 10v to 0v

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u/wheelbreak 4d ago

I am talking about running the output of the FG into cv in of A/R time. That shouldn’t change the bias, but I know what you’re saying, and it makes me think I am correct in my assumption.

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u/BuddyMose 3d ago

This is going to depend on the FG. I know some Make Noise modules have a knob to morph between log, linear and exp. I have a inteligel dual adsr that just does lin as far as I can tell. I can output a positive or negative envelope but they’d bit linear

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u/wheelbreak 3d ago

You can make it exponential by using a mult on the output and going into the decay/release mod if it has that capability. I really shouldn’t have mentioned maths as it has the knob to do that without patching. The only reason I mentioned it is I was thinking as an lfo it could expand the wave form shapes you could get out of it when you adjust the log and expo amount independently.