Use the old school av output cable for sound whilst using the hdmi to dvi converter, apparently that works.Pedro has you covered.http://www.youtube.com/watch?v=T6uF7hYSA8Q
(it has no 3.5mm jack).
On an xbox, just use the av cable for sound.
Here's the issue.When the HDMi plug is plugged into the console, I'm unable to plug in the whopping great big plug that has the RGB + audio cables, and vice versa. So I can't run HDMi + the av cables for audio, it's one or the other.
run an optical cable for sound, I am pretty sure that still runs when HDMI is plugged in
I had the same problem years back, removed the plastic shroud around the connector for the AV cable, then they both fit.