## making a 50 cent tuning system

Dec 23, 2008 at 2:35pm

# making a 50 cent tuning system

I want to make a midi implementation of a quart tone system, based on the following expression that is the abstraction of mtof

expr (440. * exp(.057762265 * (\$f1 – 69.)))

I am not very good at maths, so what I want to do is to divide an octave in 24 parts.. for an instance, instead of having relations like c, c#, d, I want to have c – C#1 – c#2 – d

where c#1 c#2 are quart tones

#41441
Dec 23, 2008 at 3:02pm

This equation will do what you’re looking for. It uses MIDI note value 69=440Hz and works in quarter tones from there.

lh

– Pasted Max Patch, click to expand. –
#147555
Dec 23, 2008 at 3:09pm

i know that it does.. the only thing i don’t know is which float number to use to make the conversion to a quarter tones (50 cents relation) instead of 100 cents relations

#147556
Dec 23, 2008 at 3:14pm

Apologies, I meant the equation I included in the compressed max file posted underneath. To view it, highlight all the text including the —— bits at the beginning and end, copy, then open a new max document and paste it in. If you use max 4 then it won’t work, but the equation is:

[expr (pow(2.,((\$f1-69.)/24.)))*440.]

where the value “24″ is how many divisions you want per octave. If this value was 12 the equation would behave exactly as the standard [mtof] object does. It is another way of writing the equation you had in your first post.

lh

#147557
Dec 23, 2008 at 6:07pm

[gangsta~]

#147558
Dec 23, 2008 at 7:52pm

On 23 Dec 2008, at 18:07, Mike S wrote:

> [gangsta~]

You beat me to it.