F12 speaker "click" on lenova T61

[William Henry]

Has anyone noticed the speaker "click" or "bang" once if there is any sort of audio activity.  It does not repeat for any length of time but sounds off when there is any sort of speaker activity - so a few times on boot and anytime there is a mail notificaiton from Zimbra etc. 

Since moving from F11 to F12 on my T61 I'm having this issue with my external speakers. It's louder than the normal audio so it's distracting and sometimes a little startling.

Regards,
William