On. But I do take them off sometimes. For my speakers it makes almost zero difference for the sweet spot, but does give a more open sound for off-axis.

In addition to the other advice about the speakers, apartment living w/ neighbors or roommates means there will be compromises.

I’d add a good set of headphones that can be driven fine by your receiver/integrated (like Senn HD600) w/ an extension cable that reaches your listening area comfortably is a good thing for nighttime music and movies. I have a roommate and when either of us go to bed and the other is listening or watching TV, we switch to the headphones so the other is undisturbed. The Senn HD600s are good for this because they sound great from the receiver’s headphone out and are comfortable. I have a 10’ Grado headphone extension cable to reach the couch with plenty of slack to spare.