Pitch shifting , lenght and BPM conversion

[moody33]

Hi all.

I need a formula.

I have a sample with a lenght of (x) ms at a given BPM.
I want to pitch shift this sample, and I want to know the new lenght of the sample once it has been shift.
Then I want to know the new BPM according to the pitch value.

So, sample lenght+ pitch shift=new bpm

Any idea? A formula could be useful.

Thanks you.

[bmoussay]

Hi,

Maybe the formulas are something like:

New Length = Original length X 2^(Pitch Shift/(-12))

where Pitch shift is a value in semitones and ^ means "power"

and

New BPM = Original BPM X 2^(Pitch Shift/12)

But you have to check I'm not sure wether I've mixed things up with some minus signs or whatever, I'm not really good at maths either

Hope it can help,

Regards,

B.

[ethnix73]

About he formula between pitch and bpm:
http://www.harmonics.com/lucy/lsd/tempo.html


From KVR:

semitones -> bpm scaling
1 -> 1.059463094
2 -> 1.122462048
3 -> 1.189207115
4 -> 1.25992105
5 -> 1.334839854
6 -> 1.414213562
7 -> 1.498307077
8 -> 1.587401052
9 -> 1.681792831
10-> 1.781797436
11-> 1.887748625
12-> 2

Formula: Y = X * exp(Z * ln(2)/12).

Y=new tempo, X= old tempo, Z=semi-tones

If the lenght of your sample change, it's time-stretching, not pitch-shifting...I suppose you just want to change the pitch.

How will you change the pitch in your patch? Because , i've made a little patch about the correlation between lenght and tempo. It's in the synchro and time tools add-ons.

[moody33]

Thanks you for your answers !
I will test ethnix add-on.

[ethnix73]

I used the formula by Bmoussay....He was right. not mine:(