This past Tuesday, I had an underwhelming experience with the LA Phil. The concert was an "All-American" chamber show, the first offering in their "Next on Grand" series, a celebration of contemporary American composers. The underwhelmingness wasn't the fault of the music, or not entirely. As with most grab-bag contemporary concerts, I was fonder of some selections than others, despite the consistently high level of performance on display. No, the music alone was fine. What really bothered me were the set changes.