Just got back and PI is always a multiple stop for my wife and me. Without a doubt, when we needed "a break," we went to the Jazz Club, so I agree. Sunday a week ago, there was a woman playing piano. Nice music, but pretty much quiet, very subtle atmosphere. Most of the other clubs with music are dance clubs, meaning loud amps and thumping bass.
Also, you could try the Adventurer's Club. Now I'm a major AC freak, but if you wanted some entertainment but still wanted to talk, you can go to the AC and not attend shows in the library, treasure room, or mask room. As shows break off, the lobby can get quiet. But if you don't see the shows, you're missing a lot. As adults traveling without kids, we find this, and Jimmy Buffet's Margaritaville on Citiwalk, to be excellent.
Pat