Have Sky put a murmuring crowd noise on in the background? I kind of get it with Football, but it seems totally unnecessary with Cricket. I've watched plenty of games being played out in virtual silence, as have most people who are watching this I would have thought.
Edit. It's just plain weird. There's no change in tone when the ball is crashed to the boundary. If it was silent you wouldn't really notice it, but there's something jarring about the ball racing to the boundary to a soundtrack of "murmur, murmur, rhubarb-rhubarb".