http://bugs.winehq.org/show_bug.cgi?id=35683
--- Comment #1 from fdssfsfsfd@master.ms --- More information:
Tried 5.1 sound test file and the output is normal and exactly identical with mplayer running on 6 channels (because of my asound.conf, otherwise I just hear rear) VLC player in wine on 'automatic' or directX or some other output all the same. So that leaves only wine's direct sound implementation as the culprit.
Also just build wine-stable-1.6.2-1 (AUR archlinux package) from source and the issue is identical.