Also from Salzburg: Plácido Domingo introduced his 150th new role there this week. (I repeat: his 150th new role.)

And closer to home, Sophie Haigney traveled throughout New York City taking field recordings of background music, the sounds we barely know we’re hearing, across the boroughs. She compiled her findings in this poetic tribute to the summertime city. ZACHARY WOOLFE

Last week, I reviewed the first three concerts in this year’s Time Spans festival, produced by the Earle Brown Foundation. Over the weekend, I attended the final two offerings, both of which were spellbinding. A Saturday meeting between the JACK Quartet and the SWR Experimentalstudio of Freiburg, Germany, made for an exquisite set of surround-sound chamber music. (No great surprise, given the studio’s history of participating in electronic works by Stockhausen, Boulez and Nono.)

The show on Friday, by the piano and percussion quartet Yarn/Wire, was devoted to Alex Mincek’s impressive “Images of Duration.” At the micro level, each movement sounded distinct, and finely etched; in its totality, the hourlong work had a dizzying, hallucinatory quality. Much of that effect seemed to be a result of a single compositional strategy: namely, Mr. Mincek’s decision to tune the two pianos a quarter-tone apart. You can hear the peculiar harmonic mystery that flows from this choice in an excerpt from Yarn/Wire’s new recording of the piece.