I use web-audio to play mp3 sound files and it works well when building with crosswalk 18.
The exact same app doesn't play any sound when building with crosswalk 19 (which I would prefer to use as it fixes a security issue that exists in crosswalk 18).
This is a known issue in crosswalk 19 :
I will continue to use crosswalk 18 while waiting for a crosswalk build in intel xdk that can play sounds.
Have a good day.
Alexandre -- see this FAQ for info on how to experiment with some later versions of Crosswalk in your build (note, the changes only apply to the Crosswalk build, not to debug modules) > https://software.intel.com/en-us/xdk/faqs/crosswalk#crosswalk-unlisted-build < However, based on the comments in the second Crosswalk Jira bug, those later versions may also not work.