Any standard methodology for range mapping?

Manual CV → (something) → Bogaudio 8:1 module, but I want full left to select input 1, full right to select input 3, center to select input 2.

The ideal transition points in the manual CV would be at -3.333 and +3.333.

In SuperCollider or Pd, you’re working with numbers and math ops and I’d have this sorted in about a minute.

I’ve been fiddling with Bogaudio Offset for 40 minutes and I just can’t get it.

I think where I’m getting tripped up is that the voltage mapping of the 8:1 module is not clear. It seems to be CV * 4/5 – then, the input from manual CV is twice as wide as the unipolar range that’s expected, and I want to divide that range into three, so CV * 4/5 * 1/6 = CV * 2/15 = CV * 0.133333 … then I set the Offset module to “scale, than offset,” and tweak the offset knob until the -3.3333 transition point is working. Then I get an upper transition point of about 4.1 V, not 3.3333. (Edit: That’s “sorta” OK actually, but… c’mon, it should be possible to get closer.)

I find this a bit frustrating because I know the result that I want, and it’s a gradeschool math problem, but somehow it’s inscrutable in CV land.

There really must be a standard way to do this. It shouldn’t be a hard problem.


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I use a adjustable voltage switch and a voltmeter to map out CV to parameter mappings. Every module and every parameter is different, with no standard I have seen.

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The Bogaudio documentation is pretty clear that the 8:1 module allocates 1.25 V per step, and it works flawlessly for me. So if 0 V is step 1, then 1.25 V would be step 2 (something like 1.2499 would still be step 1). And it goes on up from there.

I’m not sure what you are trying to do with the Offset module, and how it relates to your use of the 8:1, but Offset is also very precise, and works intuitively for me.

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@k-chaffin @DaveVenom Thanks for the input.

Sure, I admit that it was my own brain-lapse earlier this morning that I just couldn’t see it. I think I went wrong with trying to “feel” how to do it in Offset at first (which is always the temptation with modular – I’m just not good at this approach though, lesson learned, for my own thinking style I should always get the hard numbers first, I didn’t do that this time.).

I did eventually figure out that it’s 1.25 V per step.

The step 3 - step 4 transition, then, is (4-1) * 1.25 = 3.75. (I’m so used to counting from zero that I think this threw me as well.)

Then scale should be 3.75 / 20 = 0.1875, and (if it’s “offset-then-scale”) offset = +10 (which actually works).

But, it’s easier with Count Modula Voltage Scaler: in min = -10, in max = +10, limit A = 0, limit B = 3.749.

So Voltage Scaler needs to move to the front of my lexicon – if the desired boundaries are known, it’s always going to be more intuitive to just specify the boundaries rather than deriving coefficients.



In V1 I got very attached to the RJ Modules “RANGE” module for rescaling CV ranges to rational (for me) ranges. But since RJM did not make it to V2, I’ve just dropped that approach. So now I use AS “Triggers MK1” adjustable voltage source with Count Modula “Volt Meter” to map CV and document it for my favorite modules and then use BOA “Offset” to rescale where needed, although that is much harder for me to do than with “RANGE”, but that’s what I have.

The nice thing is that after mapping out the “eigenvalues” (the CV voltages that produce distinct state changes in a receiving module) for my favorite modules and documenting those, I can feed those CV’s into sequential switches such as the Count Module SWITCH 8-1 or 16-1 and then sequence CV control of my favorite modules. Since DM SWITCH takes CV in rather than using parameter knobs, I use NYSTHI “FIXED VOLTAGE SOURCE” for provide the eigenvalue CV’s to the SWITCH. I save these NYSTHI FSM setups as “selection” files that I can reuse.

Occasionally, I will use a knob based sequencer such as Count Modula 8 or 16 STEP SEQUENCER where I enter the CV eigenvalues manually into the knob slots. CM is just my favorite, but there are many as talked about in the beginner friendly sequencer thread.

For scaling voltages there is Voltage Scaler from Count Modula.

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Yeah, I should play with CM Voltage Scaler. It will probably do what RJM Range did with the exception of the digital voltage displays on the panel. Even though V2 is just 6 months old, I’ve already forgotten why I made certain decisions as I was trying to migrate my extensive patch collection to V2.

I still get confused as to whether Offset does scale before offset or offset before scale. I usually have to turn both knobs while watching the voltages to dial in what I want to accomplish.

It can be either. I simply go to the context menu “order of operations” submenu, and check which configuration is active, and change the setting if I need to.

Ah, I learned something here! Thanks.