Chrome and Safari seem to ignore the http cache headers for html5 audio files. When you are programming a game that can be fatal. First it delays the playback, second you get at least one http request per play(). So what can you do? Write a html5 Cache Manifest!
Also at least chrome seems to have a limit on the number of <audio> elements that can be created. You notice the problem when you call play() on an audio file and nothing happens anymore. My solution to this was to create a pool for audio elements for reuse.
With those two techniques I'm now able recreate the sound of a gatling gun by playing individual bullet shots, yay!