Nigel G:
In HiFi apps. transformers are mostly history (except for those tube enthusiasts)
But, in commercial sound, these things are totally indispensable. In a large office building with 5k loudspeakers for sound-masking you will find 5k transformers! I know some efforts were made to go active, but they fizzeled! Every school communication-system or office paging system has them. The death of the audio transformer has been greatly exaturated!
Altek, Lowell, Atlas, Midle Atlantic, Jensen, Rauland are just a few mfgs. who still make them in the US! And I could not immagine our phone (pots) or radio/TV to work without!
E