I have imported ogg and m4a versions of some music and one sound effect.
set the music to play with a loop on start of layout.
The sound effect happens when you tap the screen.
On Chrome on the desktop, it works great.
On Chrome on Nexus 7, I get no music, and the sound effects are out of sync, e.g. tap once, get good sound, tap immediatly a second time, a long delay before it plays the effect again. If I tap lots of times, I sometimes get one sound, sometimes a second after a long delay.
On iphone 4, ios 6, I get no music, but the sound effects are perfect, if I tap 3 times quickly, I get 3 sound effects quickly.
The exported project is here