Linear Pitch Change

Butch Moore wrote on 9/9/2010, 10:45 AM

This must be my day...

I have a historical 30 minute speech, transferred from 1/4" audio tape to digital. No problem there.

Here's the problem. The speed of the tape is too fast at the beginning and linearly slows down across the length of the tape.

Using Sony "Pitch" in Sound Forge, I can closely approximate the correct speed at the beginning and end. But, how can apply a linear pitch/speed shift across the entire audio file, such as using keyframes with video.

Any brilliant ideas? (Help me with this one and I'll quit for the day!)

Thanks!

Comments

Chienworks wrote on 9/9/2010, 10:54 AM

Have you tried Effects / Pitch / Bend in Sound Forge? That lets you specify beginning & ending pitch, as well as a handful of points along the way.

The problem is that the recorder used was rim drive rather than capstan drive. The takeup spool ran a constant speed, but as it filled up with tape it would pull the tape faster and faster. This means that the speed change is greater at the beginning than the end, so to get close you'll have to add a few inbetween points in a curve, gradually changing the speed less and less.

Butch Moore wrote on 9/9/2010, 11:04 AM

Kelly,

If you're ever in South Carolina...I owe you a steak dinner!

Thanks

farss wrote on 9/9/2010, 2:48 PM

i'd add to use the newer pitch change system in Vegas rather than the older one in SF. Elastique is miles better and it's free in V9. The latest version of SF also has Elastique BTW.

Bob.

Butch Moore wrote on 9/9/2010, 5:56 PM

Bob,

Thanks for the tip...but sorry, only one steak dinner per problem!

Thanks!