Build system has been updated to crosswalk 188.8.131.52 (labeled canary or beta). This fixes all the audio problems that I have seen. Volume controls work, volume is loud, both for webaudio and audio tag. Let us know if you continue to see audio problems.
You don't need to update XDK, just close and reopen the build tab.
IntelRobert just some feedback from my experience. The audio works great now as media volume but for me the tags still don't appear to work.
Sorry, tags do work for my sfx in the "Sounds" folder... but my background music in the Music folder won't mute.