On Friday, 2 September 2016 15:30:53 UTC+1, The Natural Philosopher wrote:
I'd like to be able to walk into any room and select what I hear and the
volume I hear it at from a control (wall mounted, maybe?) in that room.
There would ideally be a single centralised source which fed a signal to
every room.
TBH, this is where Id be thinking of running '100V line' kit round the
house....

That is what I did (I had some spare wiring from a former underfloor heating installation).

Doesn't provide channel changing though. I suppose it might be possible to extend the 'up' and 'down' buttons on the DAB radio round the house too.

Owain