Collaboration has been good for Cantus. The eight-member low-voice ensemble has gained a reputation for its a cappella concerts with intriguing mixes of music but also has taken to inviting other ensembles to perform with them and see how their muses jibe.

And the results have been favorable, be the Twin Cities visitors a group that originally inspired the formation of Cantus at Northfield's St. Olaf College (Chanticleer), a legendary all-woman group rooted in African-American traditions (Sweet Honey in the Rock) or an ensemble of Norwegian women that shares its name (Cantus).

But no Cantus collaborator has been quite as popular as the Canadian Brass, which for over 50 years has been the world's most celebrated brass quintet. You can frequently find its name near the top of the classical album charts, and the fivesome from the north is known for being big-time road warriors, playing concert halls around the world in their blue suits and white tennis shoes.

On Sunday afternoon, Cantus and the Canadian Brass connected up at St. Paul's Ordway Concert Hall, and there were some inspiring moments to be enjoyed. But most of them happened when the groups were separated from one another. When they combined their forces, their disparate dynamics became an issue. Even with the assistance of microphones (something I'd never seen Cantus use over the years), the brass was blasting their harmonies out of earshot. Solo singers could usually be heard, but the textures beneath them were virtually inaudible.

Granted, the blend might have been better in the balcony than at close range — and perhaps it sounds great on the livestream that's available through next Sunday, for we have some terrific recording engineers in this town — but I felt this an unsuccessful pairing.

The sonic imbalance wasn't the only issue. The two ensembles also bear very different performing styles. The Canadian Brass is regarded as among classical music's groundbreaking groups when it comes to engaging with an audience. They've always been whimsical and playful, introducing tunes with deadpan humor before demonstrating that they're very serious musicians on exceptional interpretations of music by J.S. Bach or, on Sunday, Mozart (via a very fine arrangement of the Overture to "The Magic Flute" by Fen Watkin).

By contrast, Cantus seemed overly serious and a little stiff on Sunday. While a preview of its upcoming mountain-flavored spring concerts proved intriguing — particularly Reena Esmail's "TaReKiTa" and a Chen Yi arrangement of a Tibetan folk song — and the traditional spiritual, "Steal Away," boasted a splendid solo by baritone Rod Kelly Hines, the vocal-brass blends too often proved a disappointment, the horns drowning the harmonies on songs that require a delicate delivery to transmit their heartbreak, such as Joni Mitchell's "Little Green" and Billy Joel's "Lullabye (Goodnight, My Angel)."

Yet there were instances in which the brass quintet softened its delivery considerably, such as on Cantus' signature song, Franz Biebl's "Ave Maria" and the popular Hawaiian song, "Aloha 'Oe." And Cantus finally loosened up for an encore that spoofed Meghan Trainor's "All About That Bass" in tribute to Canadian Brass co-founder Chuck Daellenbach, who's been manning the tuba in the group for over 50 years. It was the only time all day that the two groups' spirits seemed totally in sync.

Note: A streamed version of the concert is available on-demand through Sunday at cantussings.org. Pay-what-you-can admission starts at $5.

Rob Hubbard is a Twin Cities classical music writer. Reach him at wordhub@yahoo.com.