Speed up an audio track

vocals are always going to be the worst thing to get artifacts when time stretching audio.
 
I would re-record the vocals at the higher tempo instead of trying to stretch it.

Skarda
What is the best way to speed up audio tracks from 72 bpm to 100 bpm. (mainly vocals) The midi instruments are easy. I noticed the stretch tool does this but sounds terrible and Also I would like to change by bpm Not percentage so I can keep the integrity to the midi tracks.
   -Will voices sound like chipmunks or lose pitch.
   -Should I be using a 3rd party tool withing Sonar X3 Producer?
 
Thanks
Sonar X3 Producer

Did you bounce the tracks after stretching? 72 to 100bpm is pushing it but if you don't bounce/render it doesn't matter how far you stretch it... it will always sound like crap. If the render doesn't quite work you can try a different offline algorithm which sometimes helps.
 
There is also getting right in there with Loop Constructor. Go in and completely do all the transient splits by hand (listening to every little section to make sure EVERY transient has a split at the exact spot). This is a lot of work and based on some of my tests I like the stretch option better but I think for drastic tempo changes the Loop Constructor method might actually provide better quality. Of course this means the audio clip needs to be converted to a Groove Clip and you might be better off chopping it up into smaller clips (same goes for the Track View time stretching).
 
Again after doing the Loop Constructor Groove Clip thing I think bouncing/rendering will still make the quality better (not sure though).
 
However as Beagle said if you have the option to simply re-record the track that is preferable.
 
Cheers.