Thanks, Pucci ^ quite right.
There are of course two different ways to use a mobile, the right way and the wrong way.
I remember when a bit of a problem left me in LHR instead of LTN and I had to take a bus to pick up the car, I called my wife from the coach to tell her where I was, and the lady sitting next to me complimented me on phoning without being audible

- says he, blowing his own trumpet, but softly

.
Whatever, sotte voce is normally adequate on a mobile, and cupping one's hand over the phone helps too.
Now about those MP3s ...