Growing up changes the meaning of a late night. The Mack Brothers seize that feeling on “Sleepless in Seattle,” an indie rock single from Philadelphia brothers John and Matthew Mackara. The title comes from John’s own phrase for those anxious, can’t-switch-off hours, and the song’s stated concern is the friction between the past and the present. That premise hits hard because it is familiar without being...

Listening to Libby Ember’s single “Alibi” is a study in strange emotional temperatures. The sound is a down-tempo, sun-dusted blanket of soft guitars and gentle synth pads, the kind of arrangement you’d put on to feel safe. But the feeling it leaves behind is a deep, architectural cold, the kind you find in the shadowed corners of an old stone church long after the...