There are days when you throw a rock into a pond and it's just a rock in a pond.

But sometimes, very occasionally, you stumble upon a day so perfect -- the sun so bright and clean it's like a hug, the sky so blue you could slice it as dessert -- that when you throw that rock into the pond, it seems as if the ripples that ensue could go on forever. That's the way I felt when I heard the Concordia Choir from Moorhead, Minn., one of the finest collegiate choirs in the nation, sing the first chord in Latin of Henryk Mikolaj Gorecki's "Totus Totus" in its Saturday concert at the Shaghoian Concert Hall.

The chord hung in the air: beautiful, rounded, intense. And then it dissipated in an exquisite retreat, rippling into silence, but with the memory of that sound still swirling a little in your skull.

Such is the result when a world-class choir meets the superb acoustics of the Shaghoian. I'm not sure if this gorgeous facility, which has been open less that a year on the campus of the new Clovis North Educational Center, has ever had a group of this caliber perform in it before. It was like watching a professional equestrian hopping on your prized thoroughbred and giving it a test run.

"You should feel honored as a community to have a hall as amazing as this," Concordia conductor Rene Clausen told the audience at the Saturday afternoon concert. His 72-member choir undertook the whirlwind weekend trip to the Fresno area from Minnesota in part because of the allure of the Shaghoian's acoustics.

The program ran the gamut of Concordia's repertoire, from challenging classical works (including Alfred Schnittke's Choral Concerto, sung in Russian in 16 parts and eight modulations) to its trademark Lutheran hymns. A significant portion was devoted to ethnic music, including a beautiful "Noel" sung in the Kituba African dialect to "Ka Huliau'ana," a piece in Hawaiian.

My favorites included a version of "Our Father" by Alexandre Gretchaninoff and an exquisitely version of "There Is a Balm in Gilead," arranged by Clausen itself. Through it all, the choir projected a sense of snappy, friendly proficiency that took command of the hall from the moment they briskly took the risers for the first time. Choral music isn't just about the tones that are produced -- it's about the connection between the singers and the audience. Smooth and confident yet eminently human in their demeanor, the singers in a brief time formed a bond between the choir and the audience.

At the afternoon concert, Concordia was joined on stage for the final two numbers by the five Clovis Unified high school choirs. (The evening concert featured members of church and community choirs from the Fresno-Clovis area.) The sheer power of all those voices reverberating in the hall was memorable.

Overall, it was a tremendous event: a joy to behold. I walked out afterward with a song truly in my heart.