Modern Music, the collaborative recording between longtime colleagues and jazz pianists Brad Mehldau and Kevin Hays, and composer and arranger Patrick Zimmerli (a mutual friend of both) is startling for its deep reliance on modern classical technique and arrangements.

Certainly, Mehldau is known for dabbling in all sorts of music, from pop to classical on his recordings and in live performance.

Hays, too, has branched out in recent years, from his signature, intelligent, hard swinging post-bop approach to include compositions with modern classical touches, such as those found on Piano Works, Vol.

III.

Zimmerli, who wrote the charts for this session, played saxophone in his younger years.

He composed and chose the lion's share of the material.

Three pieces are by Zimmerli, while Mehldau and Hays contribute one each; there are also readings of Ornette Coleman's "Lonely Woman," an excerpt from Steve Reich's "Music for 18 Musicians," and one from Philip Glass' "String Quartet No.

5." Those seeking a jazz recording should look elsewhere; even Coleman's standard is overly formal, with Mehldau (right channel) playing the melody in various voicings as Hays creates pulsing rhythmic and harmonic patterns in the middle and high registers.

The latter begins to swing a bit toward the middle of the tune as Mehldau takes the rhythm line, but even here, the counterpoint dialogue Hays creates moves it far from the beautiful, droning center of Coleman's work.

The section from Reich's work, which attempts, in its way, to imitate the mallet instruments, isn't nearly as forceful or convincing.

Those complaints aside, Zimmerli's compositions, sauch as "Crazy Quilt," "Modern Music," and "Generatrix," with their busy palettes, intricate cross-keyboard dialogues, and contrapuntal studies are all deeply satisfying.

His sense of melody is found in rhythmic approaches; his stuttering half-steps and tonal shifts are especially notable for their ability to play off both pianist's technical and melodic gifts, for all their busy-ness.

Hays' "Elegia," too, for its seeming moodiness is more pastoral than one would gather by its title.

In sum, Modern Music totals what its title promises, it's not a jazz album, but one in which new considerations of harmonic composition and intra-instrument dialogue are readily apparent and delivered upon with discipline as well as verve.