There was a letter in yesterday's paper from a chap who said he had a choice of watching with crowd noises, or hearing the coaches and officials. Possibly different broadcasters, or maybe Sky etc can offer two channels?
I watched a bit yesterday on Sky's FTA broadcast on their "Pick" channel.
It's HD on Freesat (147, not 144), and SD on Freeview (11) (both free, but selected matches).
There was a banner running that pukka Sky viewers (via the non-free broadcast) could select which audio they wanted ("red button" type stuff). It's not been unknown on other broadcasts (I think at one time the BBC used to support the alternative of the radio commentary for cricket?).