I've never seen a game at TBA, but watching on TV it sounds loud during big games (UK, Bama, etc.), but otherwise only loud at certain points during games - needing a big stop, after a run, or after a big basket into a time-out.
I was at UT during the Stokely years and loved going to games in that bandbox, which would just get crazy. You still had alumni sitting on their hands, but the students were on one sideline behind the opposing bench, and would make the opposing coaches crazy.
I remember being very disappointed when TBA was opened, and am still a bit envious of those great road environments in the loud smaller buildings, like the one at Illinois earlier this season. But $$$$$$$ rules all