For parents of young children, summer often boils down to a frantic search for activities that will divert their kids, even for just a few minutes. By mid-July, the situation can get desperate, so the first summer concert at the National Building Museum, heard Sunday afternoon, was perfectly timed. In partnership with Washington Performing Arts, the museum presented Reverb, an a cappella group based in Washington, on a stage at one end of its large, noisy atrium.

The all-male group overcame the cavernous acoustics with amplification, performing a toe-tapping mix of Motown, doo-wop, R&B, soul and pop standards, as well as a couple of original songs composed by members of the group. The generally capable performance was no sensation, with some modulations that never quite hit their new keys (“When the Saints Go Marching In”), some grating intonation mishaps (“Ain’t No Mountain High Enough”) and low points in some solo voices (“The Lion Sleeps Tonight”).

Such concerns mattered little for most members of the sparse audience, who were delighted by an hour’s entertainment, free, in the air conditioning and under the cover of this vast neoclassical building. No tickets are required, one can come late or leave early, and no one cares if small children ask questions, dance around or run about a bit. A few teenagers were spotted. This series of concerts continues through Aug. 10, with local performers and similar styles of music, on Sundays at 2 p.m.

Downey is a freelance writer.

Reverb. (Washington Performing Arts)