I forgot audio mirroring &amp; speakers were on I hadn't used audio mirroring until the other day when the gf hassled me to turn it on.    
I rarely use pc speakers since Vive arrived but listened to a quiet radio program yesterday so volume was up!

Gf nipped out to the shops last night so I thought I would take a look at Doom 3 I had installed earlier, it had some really weird graphic shit going on so started playing Serious Sam. Volume was too loud in my over ear hadphones so I kept switching to Steam and turning it down but it wasn't making any difference, still deafening.    
Eventually I removed the headphones and realised 5.1 pc speakers were blaring out, god knows what the neighbours thought. Thank fuck it wasn't porn!