As far as I’m concerned, the world’s best listening room is my room (or rather the room
In which I’m currently listening to music, and since I have 5 vastly different systems with very different components, the sound varies a lot).
As you get older, you get a bit wiser, and one of the many things you learn is that it is absolutely meaningless to certify something as “best”. Is there a “best” composer? A “best” artist? A “best “ singer ? A “best” wine? Indulging in such speculations is an absolute waste of time, IMHO.
Instead, one should develop an appreciation for different points of view, different perspectives, whether it in the choice of a music hall, a listening room, a loudspeaker, a wine or a composer. Can one compare Mozart to Stravinsky? Picasso to da Vinci? The question is meaningless.
I’m fortunate to own a house in the Bay Area large enough to accommodate multiple systems. My loudspeakers range from a 60-year-old Quad ESL to a one year old Klipsch La Scala to several dynamic loudspeakers. Listening rooms vary in size from over 6000 cu ft to diminutive. My ESLs I listen to in the near field about 5-6 ft away and get enveloped in their oh so gorgeous sound. My La Scalas, on which I’m listening right now to the majestic sound of John Coltrane playing the blues, are much further away, like 13-14 feet. Horses for courses.
I’ve been fortunate to visit all the major concert halls in Europe and the US and the iconic Sydney Opera House. They all sound as different as cheese and chalk. Heck, even the grungy sounding Barbican in London sounded magnificent as the great Gustavo Dudamel showed when I heard him conduct the magnificent Mahler Fifth with the LA Philharmonic a few years back. As did the maestro Ricardo Muti with the Chicago Symphony orchestra playing Brahms Symphonies 2 and 3 at the Berkeley music hall, a dowdy university performance venue.
Great conductors tune the sound of orchestras to the venues they are playing in, to the orchestras they are conducting, to the music they performing. As do great singers.
So, give up this rather futile quest to label something as “best”. One of the many things I’ve learned over the past 40+ years of listening to great orchestras and hifi systems.