Since World War II, jazz groups generally have been lumped into either of two categories: the big band or the small combo. Originally, this was more a matter of fashion than anything else, with the big bands working the dance floor while the small combos took care of the more serious fans; but with the death of swing and the birth of R&B, that distinction was rendered meaningless.

Nonetheless, the state of the midsized jazz band (eight to a dozen pieces) has remained tenuous. The advantages of such a unit were clear enough in the '30s -- sufficient voices to support intricate ensemble writing with plenty of room left for featured soloists -- but aside from the nonet Miles Davis assembled for his "Birth of the Cool" sessions, it's hard to think of any midsized jazz group that has made a lasting impact in the postwar years.

At root, of course, was economics. To take full advantage of the arrangements, a soloist is needed in every chair; but since it's more profitable to divide a paycheck three or four ways than eight or nine, holding on to star players has proven all but impossible.

Unless the band in question is part of a special project, like "African Flower" (Blue Note BT 85109), James Newton's Ellington tribute. Although Newton, a flutist and arranger, played with the Ellington orchestra during its later days, this is no ghost band; indeed, what matters most about these recordings is the ease with which Newton has captured the Ellington spirit while utterly rethinking the big-band sound.

Newton doesn't use a band as such, preferring instead to draw from a repertory of side men for each arrangement. Thus, the settings range from the brassy punch of "Cottontail" to Newton's soliloquy on "Sophisticated Lady." Yet there's never a sense of sameness to the writing; "Virgin Jungle," for example, makes its mark through the interplay between Billy Hart's trap set and Pheeroan ak Laff's talking drum, grounding the piece firmly in percussion, while "Strange Feeling" so carefully deploys its instrumental voices that Newton achieves an orchestral effect with a handful of instruments.

More to the point, Newton remains true to the Ellingtonian model while fashioning a sound that's his entirely. For example, "Strange Feeling" picks up on the angularity of the song's vocal line and extends that into a sort of new classicism that reflects the original's lush jazz voicings while connecting it to the European art song tradition. "Cottontail," by contrast, plugs directly into the upscale swing of the early Ellington band but reduces the trademark ensemble lines to a kind of shorthand, giving the piece a leaner, more modern feel.

But where the album shines brightest is on Newton's careful abridgment of the "Black and Tan Fantasy." As condensed, it's mostly a dialogue between Newton and cornetist Olu Dara, and it perfectly captures the sort of "personality" writing for which Ellington was famous. The key to any midsized jazz ensemble, after all, is creating a unified sound that allows each player to shine individually, and that's a lesson also taken to heart by pianist Muhal Richard Abrams on his "View From Within" (Black Saint BSR 0081).

A founding member of Chicago's Association for the Advancement of Creative Musicians, Abrams is no stranger to collective improvisation and briefly ran one of the few successful free jazz big bands. With his octet, though, he seems more interested in integrating composition and improvisation, thereby eradicating the traditional boundaries between written and improvised passages.

Of course, the key to making that approach work is cooperation among band members, and that's where Abrams seems especially blessed. This band is particularly long on rhythm -- in addition to pianist Abrams, there's bassist Rick Rosie, mallet percussionist Warren Smith, drummer Thurman Barker and conga player Ray Mantilla -- yet the pulse is always clear and subtle, gently guiding the ensemble without overpowering it, and that's as true of the Latin-tinged "Laja" as it is of the meditative abstractions of "Inner Lights." Best of all, though, is the loose, conversational blues "Down at Peppers," which finds trumpeter Stanton Davis in fine fettle.

There are a few problems. Although reed men John Purcell and Marty Ehrlich make a tight team, Ehrlich's tenor tone is gratingly unattractive; and on the title track, Smith's vibraphone unearths nearly every cliche' of the late '50s avant-garde. Still, given the risks Abram and company take, such failings are hardly worth fussing over. "View From Within" is the sort of gamble that demands to be taken.