What is six divided by two? It’s a way of describing the opening concert of Chamber Music Hawaii’s annual series, which kicks off this weekend with two trios featuring six different instruments.

CMH, which features local musicians, has three standing groups: a standard string quartet, a wind quintet, and a brass quintet. The series also plays mix-and-match with the musicians from each group in what it calls "Tresemble" concerts.

This weekend’s concerts will be a Tresemble concert, featuring a Beethoven trio for violin, viola and cello, and a trio for piano, clarinet and horn by German composer Carl Reinecke. The program promises an unusual combination of moods and emotions.

Beethoven, known for turbulent emotionalism typical of the "Sturm und Drang" period of late 18th-century Europe, produced a light-hearted, amusing work in his "Serenade in D Major, Opus 8."

"It’s a delightful, joyful work," said violinist Claire Hazzard, who will perform with violist Mark Butin and cellist I-Bei Lin. "People will find it more uplifting than that brooding, dark quality Beethoven can have."

"There are a lot of musical jokes in this piece. It will be in a minor mode, than he’ll switch 180 degrees and go into a scherzo (a cheerful, optimistic work) … He hops from one mood to another."

Though the mood throughout the six-movement work is generally light, Beethoven’s creative genius will be on full display. "It begins and ends with the same melody," Hazzard said. "He takes the same themes and presents them in many different formats and moods, from bombastic to light-hearted. Beethoven’s great that way, but then it’s a challenge for us as musicians to interpret."

The second piece of the concert, Reinecke’s "Trio in B Flat," features University of Hawaii at Manoa piano professor Jonathan Korth with clarinetist Jim Moffitt and Jonathan Parrish on horn.

Reinecke (1824-1910), though virtually unknown today, was one of the most respected musicians of his time, acclaimed as a concert pianist, conductor, composer and teacher. Music lovers interested in historical performance style might be intrigued by several piano-roll recordings he made in 1905, making him the earliest-born musician to be recorded.

His trio, written in his 80s, is a classic example of "late Romanticism," said Korth, who has been at UH-Manoa for three years and is making his debut with Chamber Music Hawaii. "I think the composer I would compare him most to in some ways is Schumann, with maybe a little bit of Brahms, and then he pushes the tonal boundaries of where those guys were.

"(The trio) is a little schizophrenic, in that he has a lot of ideas in tonal areas and other things, and he kind of navigates a curvy path through them all. He brings a lot of themes back, so there are recognizable tunes, but then he takes some unexpected turns."

Few works are written for horn, clarinet and piano, and Korth said the instrumentation provided some unusual challenges.

"In the standard trio — piano, violin, cello — with violin especially, there isn’t much trouble with that being heard, because the sonority is so different from the piano. Here we have two middle-of-the-road sonorities. The clarinet can function like the violin, so that it helps, but it’s rounder than a violin. … So as a pianist we have to be careful that the texture is OK for the other two instruments to come out.

"And anytime I play with wind players, there’s that added trickiness of breathing. We’ve got to phrase within their breath, which is something you don’t think about with a standard trio."

Music lovers accustomed to the grand atmosphere of symphonic performances may enjoy the intimate nature of chamber music. Concertgoers will be able to see how musicians relate to each other using nonverbal cues, Hazzard said.

"It can be very subtle. Sometimes it’s just lift of an eyebrow,’ Hazzard said.

Chamber music tends to make the audience feel like a part of the performance, Hazzard said — and in fact the musicians feel they are too.

"There’s that idea that the audience is a passive, receptive part of the concert," she said. "Not so. We respond to the audience. When you hear someone sigh, laugh or giggle, that really means a lot. We react to that."

Hazzard doesn’t even mind if people violate the tradition of applauding between the movements of a work. "If it’s spontaneous and sincere, I think there’s nothing wrong with it," she said.