Managed to get rid of the problem,I'd moved the sound card from near the GFX card to a slot further down the board cause it seemed to be picking up some sort of interferance off it,it hummed through the head phones and speakers,simply moving it back to its original slot returned the hum
but also the vocals to full again:hmm: haven't a clue what this means but I will just have to put up with some added background noise in order to here my vital sonar man
very strange in all:hmm: