Changing Speed of Audio Without Altering Pitch


(Evan) #1

I am trying to make a system where a looped region of audio can be sped up based on the parameter ‘speed’. I have tried to alter the pitch of the audio track, thereby speeding it up, and then cancel out the rise in pitch with the Pitch Shifter effect but it didn’t work - I could have altered the original pitch in the wrong place.

What’s the best way to speed up a looped section of audio based on a parameter?


(リチャード清水) #2

Hi Evan,

Because the pitch shifter effect uses a multiplier and the event pitch property uses semitones, it is difficult to find an exact 1:1 shift for upping the speed whilst maintaining the original pitch.

A common method is to separate out the individual “one shots” of the region you are speeding up and automating the pitch of the individual instruments to pitch down at the same rate the event’s pitch property is being pitched up. For an example of separated one shot instruments, take a look at the music/cassette events in the Celeste project available in the “Demos” tab of our Downloads page.

Thanks,
Richard


(Evan) #3

Hi Richard,

Thanks for the info - I had a look at the demo and I can definiutely see how one-shotting would be useful for this approach. What about with non-pitched audio like a simple sound design element such as a door opening - would this be the best way to have a parameter affect the speed of the sound?


(リチャード清水) #4

Hi Evan,

There’s no real “best” approach for these sorts of situations as it depends entirely on what sound you’re trying to achieve.

For a creaking door, for example, you can still use the one-shot method for each individual creak. You could put a loop region with a parameter condition onto a looping instrument, for indefinite creak duration.

Thanks,
Richard