Hi all,

I'm running a Mac Pro, OSX 10.4 with 2 M-Audio Studio Pro 4 speakers attached via the standard line out. Just recently, when I play anything other than music files, ie Videos, the sound comes from the internal speaker rather than my external speakers. It's the same in Real Player, Quicktime, VLC and WMV player.

I have checked the sound output settings and it is definitely set to line out, as proved by iTunes playing through the speakers.

Completely baffled, can anyone suggest a possible cause?