Interesting...

To me is more a stage than a studio.

 

It is a studio, but a rehearsal studio as opposed to a recording studio. The set up is pretty common for most rehearsal studios. Of course, that opens the question of what they're rehearsing and why. (assuming that this is indeed a current photo.)

^ As of 2 days ago, we know that it was most likely a rehearsal for their performance at the White Tie and Tiara ball, during which Elton John joined them on stage.