PC Browsers

I have recently got a new Laptop and have downloaded Top11 to two browsers Opera and Firefox but for some reason when i play the game on Opera i get no sound from the game.
Firefox and other browsers are fine just for some reason it won't play on Opera which is my preferred choice.
any idea's why?
It's not my sound as when i use top 11 on Opera and get no sound i will open youtube or something similar and sound works fine.
does top11 have issues with Opera or has anyone else had this problem cheers.

I have those settings and everything is ok

http://prntscr.com/jiofoa

(I prefer to listen to my music :o )

yes Niko all my setting are correct. just seems a fault on opera i will change it to google chrome.