Because of our local heatwave I've avoided running my amps and have been mostly listening on headphones. And with 'phones, typically I like to listen to a lot of historical/mono recordings, esp. from my (more or less) hero, Wilhelm Furtwangler. Furtwangler is unquestionably one of the greatest conductors of whom we have a recorded record, but is a bit of a hard sell, even setting aside the political questions. The problem is that with one exception (Tristan und Isolde) all of his best work was recorded live, and in mostly pretty sketchy sound. There is a solution, that I'm happy to advertise, The Furtwangler Sound. It is run by a Venezuelan conductor who lovingly restores Furtwangler recordings to pretty good fidelity and sells them as reasonably priced downloads. I encourage anyone with an interest in Furtwangler to look up Furtwangler Sound.
So with all of that backstory I give you what is IMO one of the very greatest recordings in the history of the gramophone, the Bruckner 9th, with the Berlin Philharmonic and Wilhelm Furtwangler.

16/44 FLAC download
You can draw whatever conclusion you'd like from the circumstances: recorded in Berlin in October 1944, only a few months before Furtwangler himself left German for Switzerland. But the performance is overwhelming. It is searing the in the intensity of the climaxes as well as the serenity and stillness of the quiet moments.