Time streached audio sounding fine during playback but varying in pitch after export/bounce

[Liam Savory]

So I am working on a bootleg (unofficial remix) of a song and I have had to speed the track up to 74% of its original speed as I produce drum and bass. This sounds fine during playback however if I export it or bounce it to a master track the vocals of the song stay normal as they should however a piano that is in the back ground goes out of pitch and pitch shifts both up and down almost as if it is being manipulated by a sinewave. I have tried just about everything I can think of so all suggestions are welcome. 

Thanks in advance everyone! 

[reginaldStjohn]

Is this a stereo mix or do you have stems for all the instruments?  Also, you can try different offline rendering methods to see which sounds the best.

https://www.cakewalk.com/Documentation?product=SONAR X3&language=3&help=AudioSnap.23.html

PS. When you say 74% I am assuming you mean you slowed the audio down?

[sjoens]

Slip stretching to 74% means the clip is shorter and will play faster. It should be bounced before doing anything else. 

If you're stretching/shrinking a complete song/mix, the results won't always be of professional quality. The simpler/smaller a wave clip is, the more accurate destructive edits will be.

[msmcleod]

Cakewalk uses two different pitch/stretch algorithms used, one for online render (i.e. playing in real time), and one for offline render (bouncing/exporting).

The idea is that the online render is quick and dirty so as not to impact your flow at the expense of audio quality.  The offline render is higher quality, but much slower due to the computation involved.  The intended workflow is to use the online render until you get the timing right, then use Bounce to Clip(s) to apply the pitch/stretch using the higher quality algorithm.

However, not all algorithms are suitable for every type of material.  So it's likely in your case that the offline algorithm is better suited to your material than the offline render. 

This can happen if you've chosen a totally different offline render algorithm to the online render - e.g. you're using Elastique for online, and Radius for offline.  You'll get much more consistent results if you choose the same type of algorithm.

The algorithms are specified in preferences: