Why Does Embed Make My Page Refresh/load Twice?

I have a small iframe (mid-right) with an embedded audio player.

<embed src="slideshow/streetsound.mp3"
width="75" height="25"
autostart="true"
loop="true">

Nothing fancy, however with that in there, the page seems to load twice in
IE. It fetches the SSI header, then clears it, then loads the rest of the
page 'behind the scenes', then finally displays it.

If I remove the embed, it loads the page bit by bit and you can start
reading before the rest of the page is done, which is what is desired for
obvious reasons.

Any idea why embed causes this? Works fine in FF etc.