When is a symphony not a symphony? Well, for one, when it does not adhere to a customary, specific form. Such was the case of Israel composer Joseph Tal's Symphony No. 2. one of three works performed by the Israel Philharmonic Orchestra under the direction of Zubin Mehta. In a refreshing and varied program. Mehta, the Los Angeles Philharmonic's Musical Director, also presented Maurice Ravel's Daphnis et Chloe, Suite No. 2. and the Symphony' No. 1 in D Major by Gustav Mahler.

Opening the program was Tal's Symphony, written in 1960. Not actually a "symphony" in the classical sense, it is, in the composer's own words, a "combination of sounds," utilizing the 12-note chromatic scale. Thus, instead of the usual four movements, or sections. Tal uses a different formal structure: There is a main group, which is eventually repeated twice--in varied version--throughout the work. Filling the gaps between these main sections are different episodes, which contrast with each other, and guide the way for what follows.

The "main group" of the Symphony No. 2 is characterized by the opposition of smooth, but eerie-sounding -atonal brass and woodwind passages, against the short, gruff phrases played by the lower strings. Throughout this section, Mr. Mehta was in complete control, especially in his precise handling of the cello and bass passages--which were, rhythmically, quite complex. Yet the orchestra's ensemble playing was perfectly clean and balanced, adding to the work's percussive quality. The solo tympani section towards the end of the piece was yet another example of precision: At times, the two tympanists, playing in unison, appeared to operate in exact synchronization, as though both were working under one's control: this was a pleasure to watch. The Symphony also included strangely disturbing phrases, which gradually built into loud and powerful sections: once again, Mr. Mehta was in full control, wielding a very precise energy over the orchestra. The final section involves a sudden shift, from an extremely loud fortissimo to a barely audible pianissimo--and Mehta employed finger-tip control in the transition. Ending the work was a mysterious piano, celeste, and harp trio, and the audience's reaction, which was hardly overwhelming, was also a bit baffled.

WHEN MR. MEHTA returned to the podium for the Ravel, he seemed to be in better spirits than during the opening work. Smiling, and with more confidence, he conducted an exquisite performance of Daphnis et Chloe, Suite No. 2, the second of the two orchestral suites that were drawn from Ravel's complete ballet. While conducting, Mehta became the personification of the music--his arms were fluid and graceful during the light, airy passages in the opening of the Ravel, and then became tense and stiff when the music demanded rhythmically exact cues to the orchestral players. And Mr. Mehta, like the legendary Arturo Toscannini, conducts from memory--without a score. This allows him even more freedom of movement, and he takes advantage of it, yet with a sense of controlled energy. In General Dance, the last section of the work, Mehta captured all the flavor of the carousing, boisterous theme development. This section features several passages of frantic tension, reminiscent of Ravel's Fetes (from Trois Nocturnes), written more than ten years before Daphnis et Chloe. The three sections of the suite are played without pause, and Mr. Mehta achieved true continuity among all three, finally building into a raucous and jubilant climax at the end of the work.

MAHLER'S FIRST SYMPHONY comprised the second half of the program. Although it is considered to be in keeping with traditional symphonic forms, Mahler himself referred to it as a Symphonic Poem in Two Parts when he conducted its world premiere in 1889.

The Symphony begins with a mysterious sounding passage, dominated by the recurring interval of a "falling" fourth; the interval, repeated often, becomes a basis of the principal theme. The Scherzo is a study in contrast between the rough Landler, or peasant waltz, and the lyrical middle section. This movement was perfect: Mr. Mehta and the orchestra executed the transition between the rustic dances and smooth passages with full vitality and gusto--and absolute precision.

The mock Funeral March follows the Scherzo, and utilizes the theme of Frere Jacques--played very slowly, and in the minor key. Intruding in the middle is a portion of martial music, intended by Mahler as a parody of Austrian military bands. Again, Mehta's sense of clarity effectively presented the ludicrous contrasts in the music.

The dramatic Finale, with its extensive (forty-six measures long) second subject theme, was magnificent. Mr. Mehta and the orchestra breathed life and excitement into the music, conveying a full spectrum of emotions--from the delicate, tranquil passages, to the majestic brass ensemble sections. Throughout, crispness and vitality prevailed, as the final section ended with a rousing flourish, prompting a standing ovation.

LIKE SEIJI OZAWA, Michael Tilson Thomas, or Colin Davis, Zubin Mehta is among the younger, "new breed" generation of conductors--and one of the best. As he showed this past Sunday afternoon, he can present a solid program of substantial variety, after which the concert-goer feels elated, rather than fatigued, as is often the case after the performance of a monumental work. Mehta has enough vitality to give the music--and so the audience--an emotional lift.