VERY odd audio problem with Audigy 2 on T60

[Entropy1024]

I have a very odd problem with my T60 using an Audigy 2 PCMCIA soundcard.

It works fine when I set 2 speakers or headphones in the audio settings page. If I select 4, 4.1, 5.1, 6.1 or 7.1 speakers I start go get nasty pops and crackles on the audio. Rather annoying as I bought the card so that I could make use of my 5.1 amp for DVD playback.

I have re-installed all the drivers, rolled back to old ones, used the latest ones, re-seated the card etc all with no result. The only way to get rid of the audio artefacts is to select 2 speakers or headphones. I know my amp and speakers are fine because other 5.1 devices work fine on it.

The other day I found a workaround however. If I boot up MediaPlayer when the T60 is on batteries the audio is fine. I immediately thought the mains was introducing some hum into the audio, however if I plugged the power back in the audio was still fine. If I boot MediaPlayer on mains then unplug external power and use batts I still have audio problems.
It ONLY has the fault if I boot up MediaPlayer, or indeed any other player such as VLC or DVDPro, on mains!!!

Very odd.

Has anyone got a theory as to why this happens?

My machine suffers from another problem whereby when I unplug mains form the laptop the screen can start to flash rapidly. If I plug in the mains again it comes good. I have read other people having this issue and looks like it’s a driver issue. Could this be related to the audio problem somehow?