Cantus, the esteemed male Twin Cities a cappella classical group, dares to be different with this year's annual pop program at the Cowles Center in Minneapolis.

"Covers: A Pop Concert" involves, for the first time, the performance of an entire pop album.

The Beach Boys' "Pet Sounds" is not only considered one of the greatest rock albums of all time and the first so-called concept album, but this is its 50th anniversary.

Interpreting this landmark recording makes sense for Cantus because the Beach Boys were about vocal harmonies, and "Pet Sounds" was also about musical ambition.

Mixing the Beach Boys' least sunny sounds with pop material associated with Pentatonix and Paul Simon makes for a very good, non-a cappella program, but it could have been great with a little more creativity.

Cantus' harmonies get a good workout on "Wouldn't It Be Nice" and "God Only Knows." The interpretations are faithful to the Beach Boys' originals, though obviously the close harmonies are different with the nine voices of Cantus.

Backed by a three-man band augmented by bass singer Chris Foss on guitar, Cantus takes chances on "Pet Sounds," reimagining "I'm Waiting for the Day" as a countryish bluegrass number, and "Sloop John B" as a blues battle between Kansas City and Chicago styles. The bluegrass treatment is a pleasant clap-along, but the blues sendup seems misguided, eschewing an opportunity to showcase Cantus' cascading harmonies.

Cantus curtails to a quartet for "Don't Talk (Put Your Head on My Shoulder)," creating a lovely Four-Freshmen-as-church-choir sound. And there's only one word to describe the wall of choral sound that Cantus brings to "I Just Wasn't Made for These Times" — gorgeous. The weird clarinet line at the end of the song (rendered by multi-instrumentalist Lee Blaske) is the perfect kind of quirky touch that Beach Boys guiding light Brian Wilson would admire.

Cantus' decision to offer Side 1 of "Pet Sounds" in the first set and Side 2 after intermission seems confusing and disjointed. Why not play the entire album straight through and then devote the second set to the other covers?

Those tunes include a mashup of "I Want You Back" versions by the Jackson 5 and 'N Sync; Foo Fighters' "Everlong" with too-serious lead vocals by Matt Tintes; the cute grade-school puppy-love soul song "Back Pocket" by Vulfpeck, and Pentatonix's Grammy-winning Daft Punk medley, which features real bass and drums rather than vocal versions of those instruments à la Pentatonix.

Simon's "You Can Call Me Al" is enlivened by scatted horns — plus a real horn section at the end. But the showstopper is Macklemore & Ryan Lewis' hip-hop smash "Thrift Shop." Cantus has remade it into the delightfully inspired "Barber Shop," about barbershop quartet singing with funny raps by Sam Green and Paul John Rudoi.

For its encore, Cantus gets timely, honoring two recently deceased musical heroes by weaving together Prince's "Purple Rain" and David Bowie's "Space Oddity." Too bad Cantus wraps it up with Prince's "Let's Go Crazy"; wouldn't it be nice to hear the nine men unleash their luscious harmonies on the whew-oow-oow's of "Purple Rain"?

Jon.bream@startribune.com • 612-673-1719

Twitter: @jonbream