Volume reduction of Drilling Rig and Minisub revving

[dumbot10]

I might just be a bit of a baby, but the drilling rig when you are actually drilling rocks right near you and and revving of the minisub seem way louder then the rest of the sounds in the game. If I reduce the overall game sound number it makes everything else a bit too quiet. 

Not sure if this is where I'm supposed to suggest stuff like this but it seems alright.