You may use IFRAMES but this would solve the sound problem BUT it would hurt your SEO rankings ...
One of the other options is open a new window but... this would annoy visitors or popup blockers will stop it from opening.
I would suggest you to build a nice intro page with flash and skip intro button (just in case of impatient people).
Here is some DONTS
http://catb.org/~esr/html-hell.html