You have not choose the most easy kind of game to do ! sound is really actually a part not at all managed in the same way using such or such browser.
Focus on only one browser such as chrome and preload your sounds ... you can also start all your sounds first and put them all in a muted state so you can start then all without latency unmuted them.
But if you choose this project like another just to learn C2 and because you love sounds/music change your mind ... i think you will put to many times in it for a result not working everywhere or/and not using the same method.