But on one hand I am not sure about the quality (even if I exported 32-bit float format) and on the other hand it was complicate to find out how much speed change is necessary. My first attempt was using Audacity and it really worked. It is really a hard thing to accomplish this stuff in CbB and it had been so easy with my old tape recorder (Varispeed). So I asked the same question in my own words some days ago. But in my case the tape recorder went to slow (sound to low). Hi Keni, I have exactly the same problem (some waves saved from a tape recorder). Right now i'm missing the good old days when stretching affected both pitch/tempo in relative ratio. Melodyne free standing does a decent job of pitch shift for it but time stretch not so good as it doesn't average tempo so there are many serious fluctuations that occur. Sadly, trying to stretch the pitch separately from tempo has been less than optimum and this recording is two long sets of songs so the issues are difficult. You might notice my post in that thread immediately beliw Craig's first 3. (oh well, just noticed you're there in post #3) hopefully you'll find it useful for what you're trying to do ?.

When they released that update, there was a great thread by Craig Anderton that I found very useful over in the old forum regarding this: I must admit I've had some troubles trying to get a larger complicated project to adjust tempo upwards / downwards using élastique, but I'm thinking to adjust one track as you're looking to do should work pretty easy. 'élastique Pro time/pitch' should work to do what you're looking for.

Change tempo of song in sonar 8.5