I'm having sound issues as well with my cubox i4pro and latest LE alpha.
I have sony tv and philips 2.1 soundbar (connected via hdmi-arc).
Sound settings do not seem to have any effect, sound channels, passthrough, upmix etc.
Sound/volume is way lower than on last OE alpha, or at least bass volume. Had to use the volume amplification to get the same volume out as OE alpha.
And the main issue is that some higher sounds sound very annoying like the cubox cannot keep up or cannot play the sounds correctly.
Descriping the sound is like some alley cat meowing when it is dying.
This seems only to be issue when playing videos with 5.1 audio.
It doesn't matter if it's with TV's speakers or the soundbar.
Is someone else having such issue?
Will provide logs later today and I'll also try changing the cubox to my RPI2 with latest LE alpha.