That's really the least of your problems when writing cross-browser audio code, as I learned last weekend. You can't play an audio object a second time in Chrome without calling .load(), and you shouldn't call .load() in Firefox because it introduces delays. I spent way less time converting to both Vorbis and MP3 than I did trying to get the audio API to work in a sane way. I'm not planning on installing Vorbis for Quicktime, I'm happy without it. I still don't have satisfactory audio timing on Firefox and not only can I not figure out what is causing it, every demo I find for "low latency" audio has significant latency problems on Firefox.
(Note: Theora is the video codec, Vorbis is audio. Safari and IE don't support Vorbis, Firefox doesn't support MP3, presumably due to licensing costs which I've heard estimated at $300k.)
Sorry, that was a typo (not enough sleep :), I obviously meant Vorbis. But Safari doesn't support Theora for video either (and no VP8 as well). I'd say - stay away from such crippled browsers if you can.
(Note: Theora is the video codec, Vorbis is audio. Safari and IE don't support Vorbis, Firefox doesn't support MP3, presumably due to licensing costs which I've heard estimated at $300k.)