You can verify this by looking in your Temp Audio folder (a setting in RB Prefs)
I generated a few 37 second tracks and they are about 6 meg and saved as WAV files .. these are what Undo feature relies on .. so I'd venture to say it is uncompressed audio once it gets generated. (image below)
Granted, this is in RB, but it uses BB generation ..

Another point, I believe using this folder efficiently adds a bit of stability and speed to RB.
So much so I use a separate drive with just a folder labeled Audio Temp ...
I have 6 large reliable drives and 1 of them has the single job of handling Temp Audio location. This is where track generations, any edits, and incoming (recording) audio gets stored until a Save routine happens.
It jumps around a lot, and if it is the same drive as your OS (default install) you can lighten the load on RB very easily.

There's a couple more layers to how RB handles temp files and saves, but the above should show RB does use wav format..


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Last edited by rharv; 05/12/16 12:55 PM.
I do not work here, but the benefits are still awesome
Make your sound your own!