The Yellowjackets' first release for GRP, Greenhouse, is a real gas.

The disc starts innocently enough with "Freedomland," the kind of smart smooth jazz song that marked The Spin.

It's on the following "Greenhouse" that listeners glimpse a change in the air: Strings (!) set the stage for dreamy, exotic jazz that melts in your mind, music that goes well beyond similar experiments on earlier Yellowjackets sessions.

From this point on, the band travels back in time: Russell Ferrante's piano, the understated rhythm section, and Bob Mintzer's saxophones (Marc Russo had left, though Mintzer wasn't an "official" member yet) smoke with the fire of cool jazz.

There are still some electronics employed, but generally they're arranged in a subordinate role to give the acoustic sounds an added presence.

It would be tempting to call Mintzer the catalyst of change -- his saxophone playing is more note-filled and squeakier than Russo's, a style that evokes traditional jazz -- but the new direction in sound is just as evident in the piano playing of Ferrante, the softened attack of William Kennedy (plenty of cymbals, quieter snare hits), and the articulated playing of Jimmy Haslip (best heard on "Indian Summer").

The fresh start allows the Yellowjackets to escape from under the cloud of smooth jazz and expose their "serious" side, all while continuing to place composition and melody over individual musicianship.

Calling this the band's most mature work to date belies a natural distrust of smooth jazz, so better to say that Greenhouse is loaded with personality.

Mintzer's spooky bass clarinet on "Brown Zone," the wild bop workout unleashed on "Liam/Rain Dance," and the violin jig on "Freda" are among their most memorable musical moments.

The Yellowjackets haven't changed the way they approach their music, but the newfound ability to communicate in a more traditional jazz setting casts them in a whole new (and flattering) light.