CHARLESTON, W.Va. -- No composer before Claude Debussy seems to have thought creating chamber music involving the harp was even possible.The harp is one of the oldest of all instruments (feel free to imagine biblical or ancient Greek harps). But the modern harp that changes notes chromatically when the player steps on one of seven pedals (one for each note of the scale to raise or lower the pitch a half-step) is a late-19th-century development.The complicated process involved in creating a reasonable harp part -- so the player can change the pedals to get the correct notes -- has tended to make composers shy of writing for the harp outside of the colorful way it is used in orchestral music.But Debussy, never one to follow the usual path in composition, made the harp central in his Sonata for Flute, Viola and Harp (1915).The Janus Trio -- Amanda Baker, flute; Beth Myers, viola; Nuiko Wadden, harp -- beguiled in its performance of the work for the Charleston Chamber Music Society for a concert Saturday night at Christ Church United Methodist.Janus made the opening prelude, where everyone finishes each others' phrases, an intimate conversation. The interlude teemed with swirling colors. The finale featured a spectacular smoothness of surface and brilliantly precise rhythm.The concert began with Ravel's "Sonatina in Trio," the composer's own arrangement of his early "Sonatina for Piano." Impressionism in music is often interpreted as hazy. Janus stirred the tonal colors delicately but played the harmonies and melodies with a distinctive focus.Debussy did not start a rush of composers creating new works for the medium of flute, viola and harp. So Janus and other groups wanting to play the piece have to get more music by commissioning composers to write for the combination to fill up a concert's program.The concert featured three such pieces.Kaija Saariaho, one of the best Finnish composers in the post-Rautavaara generation, was represented with her exhilarating "New Gates." Baker had to play her flute with breathy tones that gradually gained vibrancy while Myers created raspy viola sounds, as if playing with a velvet chisel instead of a bow. Wadden drew rustling sounds from the harp before providing a persistent underlying beat at the close as the music faded to silence.Janus played the first two movements of Jason Treuting's "Pluck, Bow, Blow." "Pluck" included Baker trading her flute for a banjo joining Wadden and Myers in unison on a vaguely Japanese-sounding melody that was flecked with little asides by harp and viola."Bow" featured a little melodic phrase from the viola, to which Myers added more rhythmic subdivisions to give it a gathering energy, while Baker and Wadden played notes on the harp with violin bows. It gave the harp an odd sound, vaguely like a cello, but the harp was nearly inaudible against the viola.Paul Lansky's five movements from "Book of Memory" ranged from dissonantly tonal, in "Antique Cadences," to sounding like Ravel filtered through Copland in the dancing sounds of "Bransle." "Lied" had Baker playing the alto flute with dark warmth and ended with a striking combination of flute and harp in low octaves while Myers etched a melody in harmonics high above.Myers played a long melody in the final "Lament" while flute and harp chirped along in quiet support.Each movement was framed by hushed interludes that included the performers singing in whispers while playing hand percussion such as woodblocks and little bells.The concert opened with pianist Jacob Bumgarner, a junior at South Charleston High School, making a fine account of Brahms' Rhapsody in G Minor, Op. 79, No. 2.