Corona supports 32 sound channels.
https://docs.coronalabs.com/api/library/audio/play.html
But how does that translate to browsers? Do browsers support 32 also, or less? or perhaps many more?
No point using 32 sound channels if browsers only support 16.
I could be wrong here, but I believe we handle the channels in software so you should have all 32 available to you. But you can always check yourself with this:
http://docs.coronalabs.com/api/library/audio/totalChannels.html
Rob