[mythtv-users] Using HDMI Disables All Audio?

[nospam312]

When I connect my PC to TV via a HDMI cable the sound/audio no longer
works - I am assuming the TV expects the audio to come down the HDMI
cable or my PC disables the standard 3.5mm sound output jacks.

I am using NVIDIA driver 256.53 and ALSA 1.0.21.

I have tried setting the Audio Output Driver to ALSA:HDMI and
ALSA:SPDIF in MythTV and this does not help.  Audio Output is left as
Stereo as my TV only supports Stereo.

I have checked my alsamixer and nothing is muted.

Does anyone have any pointers on what I should try to get things working?

I am using 0.23fixes on Mythbuntu.

TIA