Are VEL and MOD signal logarithmic?

My understanding is that VEL and MOD respond to MIDI numbers from 0 to 127. Is the control voltage they produce logarithmic with respect to MIDI value? My understanding is that MIDI values roughly corresponding to subjective loudness which would mean the amplitude signal needs to be logarithmic.

I just realized the proper terms would be exponential with respect to the MIDI value, or the MIDI value would be logarithmic with respect to the control voltage.

Hi @Mike1127,

I will try to reply this in short on how i understand you question.

The VEL(ocity) and MOD(wheel) output jacks in Modular V - as i assume you mean - is only channels for routing the midi values that Velocity and Modwheel send from your controller or host to modulate parameters with the same midi values. They do not convert midi values to voltage.

For example can a controller have response curve settings. This affect when a midi value is changed and send to the synth.
A midi value comming from for example modulars V’s VEL or MOD jack outputs can give the effect like you are rotating a synth parameter knob.
A parameter can respond to incomming midi values - like it does to different positions of for example a knob - with different output values that depend on the scale that parameter is coded to use.

I hope this answer your question.

Sure, I think I get it. So let me be more specific. I want to connect MOD or VEL to the AM modulation input of VCA1 or to the AM modulation input of any of the channels in the mixer. I mentioned “control voltage” because in the real synth this would have been a voltage running into the modulation input.

So my understanding is that the MIDI value of the velocity or mod wheel will affect the amplitude of the signal coming out of that channel of the mixer and/or the VCA. So the question is: is the amplitude scaled linearly with the MIDI value or exponentially?

I kinda think the answer is linearly because that seems to be how most modern volume controls in video players work (like YouTube) and exponentially is more complicated. But do you know the answer?

So you simply wanted to ask: Which respond curve do the AM inputs in the VCA output modules have?

The AM inputs for the two VCA outputs does’nt seem to be very sensitive at any point. So without knowing the excact coding or having any info about it, then i will say they are linear. I think that’s pretty much standard, unless a VCA output have settings to change the response curve or have other modulation inputs that have other response curves.

I can add that the Mixer sections 12 first AMPs AM inputs work exponential, while the last four AMPs AM inputs work linear. This info i read in the Modular V manual long ago.