Musical Chairs, Amy Poeppel. Recommended by Ask A Manager; I liked Small Admissions by the same author, which was also recommended there. I didn't like this one quite as much; I suspect that's partly because Poeppel had experience in private school admissions, but not the classical music world, and also partly because of the larger cast of characters making it less focused. But it was still enjoyable and hard to put down!
It's basically a pastoral comedy -- a group of family and friends spend their summer in small-town Connecticut, learn things about themselves and their relationships, and end up romantically paired off at the end. It's having lots of fun with that, and also with its multi-perspective storytelling; at one point we get the POV of a character who has just arrived from New York City, doesn't know anyone, and is like, "wow, these rich Connecticut people are all super weird". The classical music angle didn't really do much for me (but also I am not a musician, just a fan). One thing I realized after finishing the book is that it's a fairly white book; or at least all of the major cast members are white or unspecified race. This is made more noticeable by the fact that there are a few Asian-American characters with walk-on parts or brief mentions, to represent the younger generation of classical performers who are even better than our protagonists; but we don't get their story. Though I do appreciate that this is a book that spends most of the time with characters who are 50 or older.