In case anyone else is interested... The formula (for equal temperament,
let's not complicate matters) is
freq = freq * [ 2 ^ ( n / 12 ) ]
where n is the number of half-steps to transpose. C to D is two
half-steps. A is 440Hz. Frequency of a half-step up is
freq * 1.059463094359
If you transpose up, the duration is shorter:
dur = dur / [ 2 ^ ( n / 12 ) ]
For each half step up the duration is
dur * 0.9438743126817 == dur / 1.059463094359
This should be enough math to put together a chart. If you use a program
like Sound Forge, it will do half the work for you, so you can see the
ratios or change pitch without changing duration.
--Mark
__ Burning Rome : SENSELESS CD on Mindfield Records MindCD03 Cathartium 14
> Distributed by Dutch East India Trading, Com Four, and Carrot Top <
<
http://www.xnet.com/~mkolmar/BurningRome > < MP3 & RealAudio tracks >
On Tue, 27 Apr 1999, Stuart McDonald wrote:
quoted 12 lines Does anyone have a rough and ready chart for timestretching samples to
> Does anyone have a rough and ready chart for timestretching samples to
> different pitches? Say I have a sample in C and I want it in D: what's the
> amount of stretching required to tune it to D without the sample
> playing time being any longer than before?
>
> Stuart
>
> _______________________________________________________________________________
> Heh heh heh.
> _______________________________________________________________________________
>
>