Your first and last thoughts are correct. The new Elastique algorithm allowed them to eliminate alternate files that used to be needed for pitch stretching. The total size of the new RealTracks is therefore about 35% of what it used to be.

This change occurred last winter, as of version 2011.

If you are hearing a "strange tone" it is not caused by any changed compression of any single file. I also doubt that the audiophile version would address that. It is possible to hear the difference between the regular and audiophile versions, but only if you have good equipment, a good listening environment and good ears. Even with all that, the difference only starts to become apparent if you are soloing an acoustic guitar or piano, or mixing many tracks in a DAW (noise is additive in a mix).

With version 2011.5, you now have easy control over the tone of each track using the mixer. Play with it a bit.

Also be aware that some soundcards apply their own effects, like EAX from the Soundblaster line. Look for anything like that and turn it off.

BIAB 2025 Win Audiophile. Software: Studio One 7 Pro, Swam horns, Acoustica-7, Notion 6, Song Master Pro, Win 11 Home. Hardware: Intel i9, 32 Gb; Roland Integra-7, Presonus 192 & Faderport 8, Royer 121, Adam Sub8 & Neumann 120 monitors.