eharetea

Copy stamping with oscillations using the math behind pitch.

You can use math to create music!

Date Created:Friday December 29th, 2006 03:41 AM
Date Modified:Friday August 01st, 2008 12:28 PM

If we are talking about the C scale, each frequency is related to the middle C note by multiplying C's frequency by 1.05946 to the power of the number of steps away from C.

(meaning 12 notes in a scale, C being 0, C# being 1, D is 2...)

Lets say we start with the middle C at 261.626 Hz

C  = 261.626 * ( 1.05946^0 ) --> 261.626


C# = 261.626 * ( 1.05946^1 ) --> 277.182


D  = 261.626 * ( 1.05946^2 ) --> 293.664


D# = 261.626 * ( 1.05946^3 ) --> 311.125


E  = 261.626 * ( 1.05946^4 ) --> 329.624


F  = 261.626 * ( 1.05946^5 ) --> 349.224


F# = 261.626 * ( 1.05946^6 ) --> 369.989


etc...

So we can use this math in a stamp() expression inside of an Oscillator CHOP:

Here is a brief overview of the network:
Notice off to the side we have nodes that we will reference for stamping. We have taken the pitch of an audio file, fit it to a smaller range and made sure we are dealing with integer values.

On the Copy CHOP is where we access what the power will be, or how we control the note that will be returned.

This is where we reference the "pitch" channel's values using a chop() expression.

Oscillator by Dan Lynch
is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License
Based on a work at www.3daet.com
Permissions beyond the scope of this license may be available at http://www.3daet.com