I am honestly somewhat baffled that we are not experiencing the same things at all. Let's try this, I should be able to post URLs now. http://soundjunk.bitballoon.com/
On my PC, in Firefox and Chrome, two sounds play from that simultaneously. A symphony-type track, and a muttering track. The symphony is in the "sounds" folder, and the muttering is in the "music" folder.
Press the button or click enter, and the muttering stops, but the symphony continues.
In Opera, the muttering only seems to load, and pausing has no effect on it. Once or twice the symphony has started, replacing the muttering, but it also does not respond to the pause button.
In Droid browser (Jellybean) the symphony starts first, but "music" doesn't start in mobile browsers until the first tap/click, so the muttering does not load. On the first click within the frame, the muttering starts and is not pausable.
I am referring to the behavior I observe in Firefox and Chrome. I do not have Safari, and IE does not work on my system.