Good evening everyone : I came here because I used to have a lot of issues with audio in any version of crosswalk about 7 (sounds weren't looping, musics weren't playing at all).
I just wanted to share my experience with you : I happen to test my game on a Galaxy 2 (using an old phone makes you sure your game will work on almost any device), which had Android 4.2 version (jelly bean) installed.
Now, I tried to use my app on my professional phone (galaxy S4 mini), which had 4.4 (kitkat) on it, and I realized my audio troubles were gone !
So I installed 4.4 on my S2 (had to go to Cyanogen, since 4.4 isn't officially supported by the S2), and now everything works like a charm (even the gaps when the music loops are barely noticeable, if you leave a pause before the loop for example).
So I would highly recommend that you check the android you're using on your phone, and if you can make a test on a newer device : it definetely made the trick to me !
Hope it might help.