Nov 13 2008 | 4:40 am
In many example patches, like the transposition playground, I see a sub-patcher called "transratio".
It is an expr with the following formula... ((440. * exp(.057762265 * $f1))* 0.002273) that serves the purpose of turning pitch changes into transposition multipliers.
The issue is that multiplying by 0.002273 is the same as dividing by 440. so you end up multiplying and then dividing by 440.
In the phase vocoder example by Dudas and Cort on the c74 site, this same patcher is used, but its even more explicit: expr ((440. * exp(.057762265 * $f1))/ 440.)
Now, Les and Richard are two gentlemen that history tells me don't do things for no reason. However, I can't figure out why on earth this formula multiplies and then divides by 440. Taking those two statements out seems to yield the same results.
Any help anyone?
barry threw Media Art and Technology
San Francisco, CA Work: 857-544-3967 Email: bthrew (at) gmail (dot) com Web: www.barrythrew.com