Mozart lived in an era in which the choice of key signature indicated a particular mood or humor, a significant artistic tool for shaping aesthetic result. The composer himself reserved A major to express the rapture of contemplated, idealized beauty. Tuesday evening, the pianist Lars Vogt performed Mozart’s lovely Piano Concerto No. 23 in A major under the baton of festival director Louis Langrée at the Mostly Mozart Festival.

Its beauty proved a bit elusive, however. Mr. Vogt is a rather straightforward pianist with a uniform and measured touch. He quickly established an atmosphere of quietude from which he did not vary, but this tranquility translated into neither delicacy nor deliquescence. It was clear almost from the outset that we could depend on Mr. Vogt’s accuracy, but his sense of poetry proved less reliable. The orchestra, which has seemed less disciplined this season than the last two, followed competently but not enchantingly. The workaday quality of this performance was jarringly out of touch with Mozart’s quest for the radiant.

When Emanuel Ax introduced his rendition of the Rondo in A minor last week at the Kaplan penthouse, he mentioned its unusual rhythm of the siciliana, a dance step also featured in the Andante in F-sharp minor, which is the middle movement of this concerto. Again Mr. Vogt acquitted himself in an unobjectionable manner, but I wished for quite a bit more lyricism. In the final Allegro assai, he was indeed impressive in his separation of every note, pianism both clear and defined. But this was only technically good Mozart playing, not sensitive tone painting. Mr. Vogt opted for Mozart’s own cadenzas.

Mozart wrote the A major concerto while in the throes of composing “Le Nozze di Figaro,” and the incredible overture from that opera opened the program. This was the best playing of the evening — Maestro Langrée kept the pace quick and the accents strong. However, the corresponding curtain raiser from “Don Giovanni” — sharpeared listeners recognized that this was not the operatic version but rather a bastardized concert arrangement — was much less incisive. The opening chords were not very intimidating, the enunciation in the violin section rather slurred and unfocused. After years of steady deterioration under Gerard Schwarz, the Mostly Mozart Orchestra experienced a rebirth under Mr. Langrée just a couple of seasons ago. Hopefully, it is not now simply waddling back to its old lazy ways.

Also on the menu was the world premiere of Magnus Lindberg’s Violin Concerto. Every boy in Santo Domingo wants to grow up to be Pedro Martinez and every kid in Helsinki wants to be the next Sibelius. It was, however, perhaps unfair to Mr. Lindberg to program his latest effort on the same evening as three of Mozart’s most luminous masterpieces.

The piece projected a certain harmonic cohesion and a few quotes from Béla Bartók’s Violin Concerto No. 2. But it was difficult to evaluate the performance of violinist Lisa Batiashvili, who appeared to toil away assiduously, but, quite honestly, could have been playing the score upside down for all anyone knew. Seemingly interminable passages of feline pugnacity gave all of the string players a good workout but meandered arbitrarily among the highest — and squeakiest — notes on the fingerboard. The horns, who were superb all evening, appeared to be navigating some very difficult passages with superhuman steadiness of pitch. I have but one thought from the Bard for Mr. Lindberg, who seemed pleased with this realization when he emerged from the wings for his bow: Brevity is the soul of wit.

Last season, Mostly Mozart experimented with bringing the stage closer to the middle of Avery Fisher Hall and installing acoustical “mushroom tops” above the musicians. The result was a definite brightening of the overall orchestral sound. This year, that configuration is back and begs the question of why it is not employed during the regular concert season. Perhaps it would be a bit much for a 100 piece Mahler or Strauss work, but the Philharmonic and the stable of visiting ensembles still program many nights of Beethoven and Brahms. Having the sound reach the ear a little more brilliantly is a good thing, no?