Regular readers of these pages will remember that just a week ago, the shortest of Anton Webern’s instrumental pieces were performed at the Weill Recital Hall. Compared with such works as “Three Small Pieces for Cello and Piano,” his eight-minute String Trio, Op. 20, seems like “Parsifal.” The work, written in 1927, was his attempt to incorporate the geometrically precise linear tone-row construction of his mentor Arnold Schonberg, who, by the time he came to write the Piano Concerto of 1942, was employing a slide rule system of intersecting note sequences of his own invention.

Violinist Colin Jacobsen, violist Nicholas Cords, and cellist Edward Arron delivered a terrific performance of Webern’s String Trio on Friday evening as the Metropolitan Museum’s Artists in Concert performed a live radio broadcast at the Grace Rainey Rogers Auditorium. Not only were they able to convey the excitement and tension of this intense music, but Mr. Cords in particular was adept at communicating the loveliness of individual phrases, some only three or four notes in length. Webern’s music may have been a culde-sac, but it offers great rewards at its hidden end.

The program opened with excerpts from the Brahms Waltz, Op. 39, for piano four hands. Andrew Armstrong took the lower part while the more seasoned Jeremy Denk handled most of the melodic duties in the upper. This is sentimental music – interestingly, Brahms was more prone to flowery nostalgia as a young man than as a mature artist – and needs just the right touch of poetic filigree to pull it off. Unfortunately, except for the more rapid turns around the dance floor, this performance was plagued by sentimentality. Mr. Denk crossed that thin line between the tasteful and the schmaltzy, and much beauty was lost to empty Hallmark moments.

The evening’s two pianists and Mr. Arron were joined by the cellist Nina Lee, cello, and the horn player Eric Ruske for a solid, if uninspired, run-through of Robert Schumann’s “Andante and Variations for Two Pianos, Two Cellos, and Horn.” Even for Schumann, this is an odd piece. The composer was deeply insecure, and he allowed himself to be persuaded by his friend Felix Mendelssohn to abandon this work in its original form and let Mendelssohn and Clara perform it as just another two-piano composition. Brahms, however, appreciated the unique nature of the sonorous combinations, and later restored the Schumann prototype with a few tweaks here and there.

Truth be told, there is a reason that this piece is hardly ever performed, and it is not because of its unusual instrumentation. The variations are scattershot, the roles of the three non-keyboard instruments undefined, and the logic flawed. At one point, the horn erupts in calls that have little musical value beyond the shock variety. I’m surprised this piece isn’t sighted more often in those fashionable posthumous psychoanalyses of Schumann that have become so popular in the academic community. Still, it was important to resurrect such an ignored piece for modern ears to absorb.

Finally, Schonberg himself was represented with the throbbing “Verklaerte Nacht.” The violinist Laura Frautschi and the violist Max Mandel added weight to the string sextet. This was an ardent, if inelegant, realization, not very well blended sonically but rather rough and tumble. When Mr. Jacobsen broke a string about 10 minutes in, the group, even though on live radio, made the correct decision and began again from the beginning.

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Sergei Rachmaninoff, to many ears the greatest pianist of his century, was sometimes conflicted as a composer for the keyboard. Because of his superhuman agility and massive hands, he occasionally forgot that mere mortals needed to perform his music as well. In some instances, the composer even approached his friend Vladimir Horowitz (no mean technician himself) to edit passages that would otherwise be far above even a veteran artist’s performing level.

Rachmaninoff’s Sonata in B-flat minor now exists in the Horowitz version, but it is still devilishly difficult. It was the centerpiece of the recital by the Ukranian Alexei Grynyuk at the Metropolitan Museum on Thursday evening.

Mr. Grynyuk is a very young man, but he traversed this minefield of a score with remarkable technical acumen. The sheer mastery required to play each note accurately is worthy of special praise, and this was basically a flawless rendition. He also used intelligently fluid dynamics, launching ambuscades of chordal material when required, but also contemplative pianissimo passages. My only quarrel with this version was its lack of poetry. It was less dreamy than ruminative.

In the 1930s, when Rachmaninoff was living in the United States and recording his major works with the Philadelphia Orchestra, it was a common cinematic image to see a darkened concert hall, a piano lit by a single spotlight, and a pianist entering and sitting down to play. That pianist was Bugs Bunny, and the piece was invariably the Prelude in C-sharp minor. The very popularity of this work created collateral damage. In addition to dogging the composer, who had to perform it as an encore at every concert, the prelude totally overshadowed the set of which it is but a part, the Five Pieces, Op. 3. Bravo to Mr. Grynyuk for performing the entire series at this recital.

His version of the famous piece – which, although a prelude, actually appears second in the set – was notable for its calm and quietude. This was very dignified playing, but again seemed to be missing the essential spirit of the piece, the periapsis of the minor mode. Remember when your elementary school teacher told you that major was happy and minor sad? Well, this is the piece to which she was referring. Mr. Grynyuk built his case strongly, providing a thunderous finish to the reprise of the opening theme. However, the deep depression that haunted Rachmaninoff never took hold.

Chopin was on the menu in the second half. I have to question the inclusion of two long works – the “Polonaise-Fantasy in A-flat major” and the “Andante Spianato et Grande polonaise brillante” – that so closely resemble the big Rachmaninoff sonata. Mr. Grynyuk spent much of this evening on loud introductions and meandering thought syntheses. Better to have broken away for some more beauty (a Nocturne, perhaps), drama (a Ballade), or motion (a Waltz).The effect, even at Mr. Grynyuk’s high level of accuracy, was decidedly soporific.

His best performance was of the Scherzo in C-sharp minor, where majestic chords alternated with deliciously diaphanous arpeggiated material. This relatively short piece was, however, over much too quickly and we were immediately returned to the monastic cell of Chopin’s cerebrations. Mr. Grynyuk’s rendition of Three Mazurkas, Op. 56, was ultimately unsatisfying.

Chopin interpreters fall into two distinct categories. One group, with Artur Rubinstein as its patron saint, instinctively understands the slightly off-kilter rhythms of this uniquely Polish dance. The other side of the argument is represented by the foursquare performers – Ivan Moravec is probably the best living example – who just don’t get it. No matter how lovely their individual notes, the passage of time is simply not askew. Mr. Grynyuk, at least at this early stage, is still tied to the apron strings of the metronome.