The reason why alpha 5 sounded different is that there was a bug with stereo separation which was enabled for everything. You should be able to duplicate the sound of alpha 5 by turning on stereo separation for everything.

Crossfade in alpha 3 had a bug where the dialog let you go up to 5. It only ever did a max of 3 seconds even if you told it 5. The dialog bug was fixed after alpha 3.