Cycling 74 » Topic: Finding Octave Number

Finding Octave Number

stringtapper — Thu, 13 Oct 2011 14:38:21 +0000

I’m making a patch to explore just tuning and while my algorithm might not be so efficient (any comments on that welcome) it’s brought to a point where I need to find the octave of the input note since my algorithm has to mod-12 the input in order to derive the correct ratio from the coll object. Any ideas on how to find which octave a note is in and then multiply its (just tuned) frequency to get that octave?

– Pasted Max Patch, click to expand. –

Re: Finding Octave Number

Peter Castine — Thu, 13 Oct 2011 15:00:21 +0000

[/ 12] will give you the octave number of your MIDI note number.

As for the rest of your patch, that’s one way of doing it. Another alternative would be to store the floating point values of the ratios in your coll rather than the numerator/denominator pairs of the fractions. Something like

0, 1.;
1, 1.0666667;
2, 1.125;
3, 1.2;
4, 1.25;

etc. That would allow you to cut out three objects from the patch.

Re: Finding Octave Number

stringtapper — Thu, 13 Oct 2011 16:18:40 +0000

Duh, it’s funny how I had already figured out how the math worked going in one direction but couldn’t apply it in the other.

And double duh with the floating values. It’s not my day. Thanks, Peter.

Here’s the patch. Monophonic just intonation. Currently uses C as the base note (1/1).

– Pasted Max Patch, click to expand. –

Re: Finding Octave Number

Luke Hall — Fri, 14 Oct 2011 04:19:51 +0000

You could replace the [coll] on the left with [expr pow(2,$i1)] and get the same outcomes.

Re: Finding Octave Number

stringtapper — Fri, 14 Oct 2011 16:07:02 +0000

Thank you Luke. Thinking mathematically to make things more efficient is one of my biggest hurdles. This helps a lot.