No browser sound

[wintonian]

I seem to have an issue where sound is fine and working seemingly everywhere else apart from when using an internet browser (Firefoxe, Opera & Chromium).

This isn't a flash issue as I still have no sound through HTML5 and .wav files played through the browser, so I assume this has something to do with ALSA?

Any ideas on how to fix this one or which packages to try re-installing?

I am using Mint 12 KDE - mainly due to the fact that GNOME/ Unity hates my hardware and Mint 12/ Ubuntu 11.10 refused to even install, which is a shame as I quite like cinnamon.