calculation for semitone

[djmalan]

Does anyoıne knows how to calculate the semitones value for pitch chance ,I multiplied the the pots value by 2 from the main program (main program is for 4 semitones originally) to get 8 semitones the value of the pitch width is increased but I got different pitch change .I try to make vocader, with using diffrent values for fixed semitones.Otherwise whats the proportioın for pitch change...

[frank]

Please see the pdf at http://www.spinsemi.com/Products/appnot ... N-0001.pdf
It has the equation for calculating octave shift so you can simply adjust for semitones to calculate the required coefficient.

[djmalan]

Hi ,Me again.Thanks for the information.But there is one problem for me.I dont know How to calculate the 2^N . for 1 octave its too easy 2^1 =2, but for 5/12 octave 2^5/12 or for 7/12 octave or for 11/12 octave.My math knowledge is not enough also I could find nothing about these kind of examples at maths pages...

[frank]

I just use a calculator for those kinds of calculations or use a spreadsheet like Excel.

For something like: X=A^(B/C), you can break it apart like:

F=A^(1/C)
X=F^B

So, you need things like 2^(5/12) or 2^(7/12)

2^(1/12) = 1.059463094

2^(5/12) = 1.059463094^5 = 1.334839854

2^(7/12) = 1.059463094^7 = 1.498307077