Smoothing Time Warp over a file

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Coriolanus
Posts: 181
Joined: Tue Apr 29, 2008 3:50 pm

Smoothing Time Warp over a file

Post by Coriolanus »

I had a file(audio only) where over the length of the file the voice started out high pitched and was normal by the end of the file. As I had other files with the same voice I knew what the voice should sound like. Using time warp I corrected the file but had to change the time warp settings in various parts of the file. If I had used the setting I started with, the voice would have become to low and slow by the end of the file.

As the file stand now it on the whole resembles the original voice but in places it is rather obvious where I have changed the time warp setting. Is there any smoothing or normalization process I can use to even the voice out over the length of the file?

Thanks
DougDbug
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Location: Silicon Valley

Re: Smoothing Time Warp over a file

Post by DougDbug »

That's a tough problem...

If the pitch/speed change is constant over the song (unlikely), you could probably do something with GoldWave's Expression Evaluator.

There are expression presets for frequency modulation & tremelo, and if you can figure-out the math behind how they work, you could probably modify the expression in order to slowly change the speed/pitch over the entire file.

I suppose you could use the expression evaluator in segments too, and you can avoid any discontinuities by starting/ending your selections at zero-crossings and by starting-out each segment with the same settings/adjustments as the end of the previous segment.

In concept I think it can be done, but the details and the actual expression(s) are beyond anything I've ever done... If yo have strong math skills and about a day to play-around, you can probably do it. And, if you know how much the speed/pitch is off (mathematically), that would make it slightly easier.

Auto-Tune or Melodyne might be able to do it, but these programs/plug-ins are not cheap, I assume they are not easy to use, and they might not run in stand-alone mode or in GoldWave, which means you might need to get a VTS host program approved by the plug-in manufacturer. :(

Celemony (the company that makes Melodyne) also sells a too for removing wow & flutter (speed variations) from analog tape recordings. But, I believe it costs thousands of dollars. :(
Coriolanus
Posts: 181
Joined: Tue Apr 29, 2008 3:50 pm

Re: Smoothing Time Warp over a file

Post by Coriolanus »

Thanks for your answer.

I have already used Time Warp on the file -- I want something to smooth the whole file so that the Time Warp changes are not so noticeable. I don't want to redo the file just smooth our the changes. I tired to make as small changes as possible with each piece of time warp but they are large from the first time I used time Warp till my last use. In a 44 minute file. I changed about 35 minutes of it -- usually in 2 minute increments.
GoldWave Inc.
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Re: Smoothing Time Warp over a file

Post by GoldWave Inc. »

Try the Doppler effect. That can gradually change the pitch/speed over time. It will fix pitch/speed problems caused by weak and dying batteries in tape recorders.

Chris
Coriolanus
Posts: 181
Joined: Tue Apr 29, 2008 3:50 pm

Re: Smoothing Time Warp over a file

Post by Coriolanus »

I will give it a try and see if I can figure out how it works. Thanks for the tip.
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