Comparators - Setting Octave Range

(Jim Frye) #1

I often create notes for the higher range in a 2 to 2.5 octave range. I often grab notes from the same source (quantizer) for the bass, but find sometimes there are too many higher notes for the bass effect I want. What I needed was a way to reduce the notes to a single octave. Although this technique could reduce 3 octaves to 2. I know there is probably a module that does this, but I took a stab at creating an Octave Nutralizer using comparators. :smile:

The input range is 0v - 2.99v and the output is equal to the input minus anything over 1.00v and 2.00v.
Input - Output
0.25v - 0.25v
1.25v - 0.25v
2.25v - 0.25v

It was fun to figure out a solution.


i usually use bogaudio offset or befaco dual atenuverter for that, tho they are not as precise, unless you fiddle with the knobs, but i don’t usually need it to be precise (i just go on ear).

there’s also nysthi’s sou utils that can do what you’re after.

(Omri Cohen) #3

That’s great! Modular is so much fun :slight_smile:

(Jim Frye) #4

Hi Ben, cool find, the nysthi sou utils octave folder appears to do this. Had to get out my magnifier to read the labels. lol However the atenuverters can’t do it alone. Remember we’re subtracting 1v if the input is over 1v, and subtracting 2v if the input is over 2v. :slight_smile: Another trick I found is if you use the alikens hover tool while adjusting the scale you can get very accurate settings. For example setting it to 0.100 will provide 10% of the input at the output.

(Adi Quinn) #5

Crazy what you did here Jim! I know there’s octave folders but it’s always cooler to learn modular ways of doing things, because those seem to lead to other cool ideas. I had to stare at this picture for a while but i’m sort of getting it, maybe. Like the comparator will send out a gate when the octave is too high that is subtracted within the merge module at the setting on the attenuverter, which is probably -1 or -2 volts to get it everything down between 0-1v for your bass? my brain hurts, but i like it!


yes, what i do is different, but the result works just as well for me. i scale the cv to the range i want (say, about an octave, or two) and then i place it higher or lower with the offset. i then use a quantizer if i need it to fit in a scale.

(Jim Frye) #7

Yes that’s the idea. The comparator sends 10v out when the condition is met, input voltage exceeds fixed input. That 10v is reduced to 1v and polarity reversed by the offset module and that is applied to the merge module. Fun stuff!

(David O'Rourke) #8

The input signal is in the blue wire and the blue trace on the scope
The AO-106 is reducing it to 1 volt range (Y % C) which is from 0V to 1V
Then the (Y + C) is adding 1 volt to bring it to the 1V to 2V range
The red wire is the output and the red trace on the scope.

(Antonio Tuzzi) #9

me too me too…
sou utils


of course you can set any START and END voltage

(Josep) #10

Which means that things in Modular Synthesis can be done in multiple ways using different module combinations for it :heart_eyes:

(Josep) #11

True! … This is what makes of a forum like this, a great place to learn … Have you seen? … A single thread and 4 different ways to do the same thing! … which as you say, will “lead to other cool ideas” for sure! :heart_eyes: