Tooting Bec is my local underground station in South London and they have been playing classical music in the foyer / ticket hall for several years.
The sound quality is good. The volume level is reasonable.
I asked one of the staff whether he enjoyed the music and he said 'some of it' & he also said that it kept young people from loitering.
Next time I will try and find out more on London Underground (a part of Transport for London) policies on noise and social exclusion.
Personally I enjoy the few seconds of classical music I hear as I stroll down to the escalators.