Classical composers have long used the rhythms and structures of folk dances, but Bach’s gigues or Beethoven’s minuets were never intended for the dance floor; they don’t often back Riverdance routines or ballroom waltzes. Conversely, classical musicians rarely play transcriptions of Irish reels or Appalachian string band tunes.

Too bad. There are as many joys and challenges in playing for dancers–music that moves the body–as there are in playing music for concertgoers–moving the intellect and the emotions. Happily, there is no law stipulating that the two need be mutually exclusive. As evidence, I introduce Exhibit A, Duo Mosaic, comprised of violinist Henrik Karapetyan and cellist Martin Torch-Ishii. Both earned doctorates from the U-M School of Music and are highly trained classical musicians, with plenty of cred in that world. But both have also long moved in other circles. Torch-Ishii was a member of the cello rock band Break of Reality, and Karapetyan played with the folk-gypsy band Orpheum Bell.

About a year ago they joined forces to explore the dance music of a variety of traditions. Their just-released debut CD, Midnight Dances, hops, skips, and jumps from square dance tunes to waltzes and polkas, from klezmer bulgars to tangos. But there’s nothing uncoordinated or disjointed about this dance mix. Unifying these disparate genres are the duo’s impeccable technique, consummate musicianship, and sheer beauty of sound.

Duo Mosaic admirably manages to give the sonic impression of a much bigger band. When Karapetyan plays melodies, often in harmony with himself to provide the illusion of two instruments, Torch-Ishii becomes a one-man rhythm section, using inventive plucking and bowing techniques to provide harmonic underpinnings, and by chopping–adding dry percussive crunches–doubles as drummer. On “Gift Polka” he supplies both the oom and the pah of traditional oompah bands. Then, when it’s Torch-Ishii’s turn with the melody, Karapetyan returns the favor; the beat never falters.

Partner dancing at its best is an exquisite communication between two people, and the duo’s playing also exemplifies this interaction. Particularly on the free-flowing “Doina” and the conjoined track, the Ukrainian “Kolomyjka,” the two of them are magically, magnetically, in tune, in both senses of that phrase. (Autotune and click track dependents, eat your hearts out!)

Not everything on the album is danceable–by design. Karapetyan’s arrhythmic intro to “La Cumparsita,” perhaps the world’s most familiar tango, is glorious in its freedom and beauty of tone. “Hine Ma Tov,” the Israeli folk song, is played much slower than usual and, combined with Torch-Ishii’s velvet sound, has an aching beauty not evident when heard at its typical tempo.

Duo Mosaic is holding its CD release party at the Yellow Barn May 24, so people can dance to their music. Since there are no overdubs on the CD (how many dance bands can make that claim?), what you hear recorded is what you’ll get live. They’ve invited members of the Michigan Argentine Tango Club and have promised to play more tangos than just the two on their CD. This will be a feast for the feet, the eyes, the ears, and the whole being.