Orpheus Chamber Orchestra, known for its courageous decision to function on a high level without the benefit of a conductor, is proud, and rightly so, to have formed an agreement to commission a steady stream of contemporary compositions. “Brick” by Marc Mellits is the first work commissioned by the Cheswatyr New Music Initiative, the partnership uniting the American Music Center, Cheswatyr Foundation, NPR, Orpheus, and WNYC Radio. It was given its world premiere on Saturday evening at Carnegie Hall.

Refreshingly, the work was not performed at the very beginning of this concert, not relegated to the role of simply marking time until the latecomers could be seated and the real music begun. In fact, it was not presented until after intermission. Unfortunately, “Brick” turned out to be a rather sophomoric piece.

Six of its seven sections take a rhythmic figure, only slightly varied each time, and repeat it over and over again. Mr. Mellits espouses the diatonic – or, in some cases, pentatonic – scale, and so the individual movements have an innocuous feel to them. Perhaps Mr. Mellits can interest some car company or airline in purchasing a bit of this music for a television commercial. But let us not despair; the Cheswatyr people should have many more opportunities to select music of substance going forward.

The remainder of the concert was a decidedly mixed affair. It began quite poorly with a brutish reading of “Le Tombeau de Couperin” by Maurice Ravel.After a ridiculously rushed tempo in the prelude, which caused both oboist and ensemble to garble their phrasing, this normally delicate essay proceeded in a heavy-footed manner.

Each of its movements is a portrait of a different friend who died in the Great War. Someone – a conductor, perhaps? – needed to impart this information to these musicians. Instead we were subjected to rather clumsy interpretations of 18th-century dances. No melancholy. No poignancy. No mystery. No Ravel.

The egalitarianism of Orpheus extends to its soloists, and so Vadim Repin walked out onstage with the rest of the group for a fine realization of Sergei Prokofiev’s Violin Concerto No. 2 (it’s the one with the castanets). Mr. Repin is a violinist of remarkably controlled intensity and never fails to impress with his tight sense of phrasing and extraordinary technical prowess.

This was an almost exaggeratedly small-voiced performance. Neither fiddler nor band intoned much above a whisper throughout, but it worked rather well in this tasteful piece. I have heard much more exciting live versions – especially a lupine Kyung-Wha Chung prowling about the stage emboldening the Philadelphia Orchestra at the Academy of Music – but this was perhaps the most elegant. With Mr. Repin serving as de facto conductor, everything went according to plan.

The group’s rendition of Beethoven’s Symphony No. 8, on the other hand, was somewhat flabby, lacking incisiveness or decisiveness. The strings did not produce a particularly disciplined blend of sound; each player seemed to utilize his own set of bowing patterns, and there was no bite to their utterances. The strings dominated a bit too much, and I had to strain quite a bit to hear the horn section (a circumstance that turned out to be rather fortuitous).

The ensemble never really achieved enough technical mastery to merit a discussion of interpretative matters, but it should be mentioned that Beethoven intended for this piece to be performed in a much more raucous manner. This version was simply too polite.

I know that these fine musicians can do a whole lot better. And this night, they had no legitimate excuse. Certainly they did not have to spend much rehearsal time on “Brick.”

***

The Chamber Music Society of Lincoln Center has just completed its Mozart birthday celebrations with a three-concert survey titled “Soul of Genius,” but there were enough paper hats and balloons left over for one last blast. Thursday night four fine musicians gathered in the intimate surroundings of Rose Studio for a look at two additional works.

The studio is just down the hall from the headquarters of the society and offers an opportunity for less formal explorations of the repertoire. I envision new music directors Wu Han and David Finckel sneaking in here occasionally to try out new programming ideas outside of the office.

The ear needs to make a rather large adjustment in Mozart pieces for piano and strings. The blending is extremely tricky, and the strings often compromise their sound to match the more powerful and less adaptable keyboard, creating what Mozart scholar H.C. Robbins Landon called the “endless sausage” of unvaried tone. Further, the modern 88-key Steinway is an entirely different instrument than Wolfgang’s old fortepiano, and even more prone to sonic bullying.

Thursday evening’s group, however, featured two elegant instruments that predated Mozart, and this aided in “well-tempering” the situation.Violinist Ani Kavafian plays a 1736 Stradivarius and violist Richard O’Neill a remarkable Gasparo da Salo, c. 1590. Teamed with cellist Clancy Newman and pianist Benjamin Hochman, they chose to feature the Piano Quartet No. 2, K. 493, which may well be the most modern of Mozart’s chamber works – even more forward-thinking than the “Dissonance” Quartet.

The work was a dismal failure in Vienna, and Mozart abandoned his plans for a third piece in the genre; it was simply too advanced for Enlightenment ears. And what a sound this current quartet created! From the first notes, I knew that this was to be a special performance.

Mr. O’Neill was the real find of the evening, but only because Ms. Kavafian is so well-known around town. The work was composed just after the premiere of “Figaro” and contains much of the same sense of devil-may-care rebellion. One particularly interesting phrasing decision on this night was Mr. Hochman’s freewheeling use of rubato to shorten the endings of statements and make them seem more “in your face.” Several of the key changes are shocking, even to modern ears, and they are each generated by one held note of the keyboard. Mr. Hochman exposed them unapologetically. Not many of his elders would have had the gumption to perform in so unbuttoned a manner, but this brashness was Mozartean to the core.

The gorgeous Larghetto could have been written by Brahms,judging by this Technicolor realization. But the final movement – the most thrilling of all – contains a passage that could only have been composed by Wolfgang. After three movements of struggle between dominant piano and recessive strings, the work ends with a beautiful section for strings alone before a few final wrap-up chords. Here is what Hermann Hesse describes in “Steppenwolf” as the “icy-cold laughter out of a world beyond” that is the last word on Mozart. Perhaps this is the concert that should have been called “Soul of Genius.”