Strange sound issue

[Renesco]

Hi all I've looked about for an answer to this but can't find any clues as to the cause, basically my engine sound is only playing when I look in the direction of the back of the sub, like when I'm in command room I have to look back towards the hatch to hear engine sound, when I'm on the conning tower it's the same, I can't hear it when I have the map up for example, this never used to happen before.

I'm not sure if my fiddling with .cfg files I accidentally changed a value or if it's the fact I've rebuilt a new PC (I think when I first re-installed Sh3 the engine sounds were pervasive like before, I can't be certain though)

The thing is I'm used to having the diesels roaring all the time when I'm playing this game, and now that they've gone partially missing I'm finding it a huge immersion breaker, all I hear is the sound of water when I'm looking through periscope forward and it's annoying not being able to hear the engine state.

Any ideas what could have caused this?