I am currently working in a music project mainly in Reaper. I am at the mixing stage and have exported some partial stem mixes as 44.1khz 24 bit wavs and brought them into Vegas 12 Pro (I probably will be going to 15 once critical bugs have been ironed out). What I am doing is switching to 88.2khz 24bit in the project setting, changing the 'Stretch and resample' setting to 'Best', and using the 'lock to stretch' option set to 12.000 in the event audio properties of each track in order to double the playback speed. I then am playing the mixes out into a real reverb space and recording the results straight back into Vegas at 24/88 via several microphones on several new tracks. I then use the 'lock to stretch' options on the newly recorded tracks set to -12.000 to half the playback speed, and set the project settings back to 24/44 and rendering out to 24/44 to insert the new sections of the mix back into the Reaper project.

What I am looking for is some confirmation of what the most transparent method of doing the speedup and slowdown is. Ideally what I would like is to have the original mixes sped up simply by doubling every sample (if that actually is a workable method). In the event audio properties in both the Classic and Elastique there are a range of different modes, but the box that allows you to select them greys out immediately as soon as you select 'Lock to stretch'. Does that mean that it only uses one internal method for those stretches? I was guessing that at a straight speed halving or doubling the effect would be fairly transparent, but I am hearing a big difference between Classic and Elastique. I am edging towards 'Classic' mode being the more transparent one, but can anybody give the definitive answer, please?

(If anybody is interested, the reason I am speeding up to play into the chamber is because that way you effectively double the length of decay, and also you play the audio through a higher register in the chamber speakers, which give a different response to the lower end).