Hi Brittany,I don't know about Garage Band, but Audacity uses an algorithm called soundtouch, which is an implementation of the synchronous-overlap-add method. Here is a link to the library used, and there is a link on this page to a nice discussion by the author of how it works:
http://www.surina.net/soundtouch/ -Chris On 8/11/2011 11:11 AM, Brittany Guidone wrote:
Dear List, Does anyone know what happens in Garage Band or Audacity when you change the pitch of a voice in those programs? The voices are not getting faster or slower when I change them 4 semi tones. But I want to know what is being done to the voices when I change the pitch. -Brittany Guidone
-- Christopher Brown, Ph.D. Associate Research Professor Department of Speech and Hearing Science Arizona State University http://pal.asu.edu