I ran into this while programming a musicbox card generator. Started with different libraries but everytime there was a glitch somehow. The lag on normal audio implementation was bad, no multiple plays... eventually ended up using lowlag library + soundmanager:
http://lowlag.alienbill.com/ and http://www.schillmania.com/projects/soundmanager2/
You can check out the implementation here: http://musicbox.grit.it/
I generated wav + ogg files for multi browser plays. This musicbox player works responsive on ipad, iphone, Nexus, mac, pc,... works for me.