[linux-audio-user] transposing frequency

[Lars Luthman]

On Sun, 2005-12-11 at 22:37 +0100, Atte André Jensen wrote:
> Suppose I have an A with a frequency of 440 hz. Which formula should I 
> use for transposing x semitones up/down? So which frequency would the Bb 
> a half step higher for instance have? What about cents (1/100's of half 
> steps)?

To transpose X semitones up, multiply the frequency with 2^(X/12). To
transpose down, just use a negative X. For C cents it should be
2^(C/1200).

Bb above A440 has the frequency 440 * 2^(1/12) = 466.16.

-- 
Lars Luthman
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