feisty sounds

[Roger Searle]

Sounds are partially working on this feisty install.  Amarok goes great 
so at least I know that I have codecs for mp3 files and that the onboard 
sound is working in some way. 

I have installed via automatix all the available multimedia codecs, 
mplayer and firefox plugins, and non-free audio and dvd codecs. 

Yet any random youtube video has no sound, nor do I hear anything if I 
go to system settings > sound system and click the "test sound" button, 
where I have tried either ALSA or auto detect as the audio device. 

Any tips on how to properly test and resolve this would be appreciated.
Cheers,
Roger