Forums > MaxMSP

### Ptich to Time Ratio?

Apr 26 2006 | 12:52 pm

Is there some kind of relationship between the pitch and time of a loop? What Im trying to do is set a playback speed for a loop. Say 1.5 times faster (increasing the pitch of the loop) and then having a gizmo~ object shift the pitch back down so that the loop will be as close to its original pitch as possible. Is there a relationship between the playback speed and the numbers i send to gizmo~ ? Is there some function or operation to find out this ratio if it exists?

Thanks for any help- or any other tips on how I might go about correcting the pitch of a loop as its playback speed changes.

Apr 26 2006 | 1:34 pm

Hi, look for the transratio abstraction. I’m pretty sure it is hidden
somewhere inside the examples folder. It translates transposition in
terms of MIDI notes up/down to playback rate.

Best,
Trond

Apr 26 2006 | 2:21 pm

if i understand your question, you’re trying to alter playback speed of the
loop without altering the pitch. gizmo will do this for you.

if your playback speed is X, then you should multiply the pitch by 1/X .

the relationship between playback speed and pitch is 1:1, meaning if you
double the playback speed you double the pitch, if you halve the playback
speed you halve the pitch. So if you want to keep the pitch constant while
you double the speed of playback, then you should halve (1/double) the pitch
of the loop after you speed it up.

regards,
George

Apr 26 2006 | 2:34 pm

On Apr 26, 2006, at 8:52 AM, Darek Rossman wrote:
> Is there some kind of relationship between the pitch and time of a
> loop?

The long answer is that it is complex and depends on the amount of
noise versus harmonic content. Try running white noise through your
looper some time and you’ll see what I mean.

The short answer is that the pitch shifting ratio is *usually* close
to the inverse of the playback speed. For example, 0.5x speed and 2x
pitch shift, 2x speed and 0.5x pitch shift.

> Thanks for any help- or any other tips on how I might go about
> correcting the pitch of a loop as its playback speed changes.

You might try a granular solution, such as [gran.groove.file~] from
my GTK. Visit the URL in the signature.

—–
Nathan Wolek
nw@nathanwolek.com
http://www.nathanwolek.com

Apr 27 2006 | 12:10 pm

thanks for the help….much appreciated

Apr 27 2006 | 1:08 pm

by the way, thanks a huge amount for the gran toolkit…its exactly what i needed

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Forums > MaxMSP