Wadada Leo Smith is an avant-garde jazz musician your mother could love.

Though Smith has never compromised his dedication to freely improvised music, his sound is engaging and easy to enjoy: tart, lyrical, often delicate, and always rich in the pregnant silences between notes.  He is, in many respects, the greatest successor to Miles Davis in his use of silence, texture, and rhythm in jazz trumpet.  With Smith, however, there are no cute pop tunes, and there is little sense of conventional swing.  And still—there is plenty in Smith’s art that is easy on the ears.

Spiritual Dimensions is an exceptional exemplar of Smith’s work as a bandleader and improviser, offering two discs of captivating live music: one each from his more traditional “Golden Quintet” and his sprawling funk band, “Organic”.  No doubt, this music is the apotheosis of Smith as a Davis acolyte.  Look here: a largely acoustic quintet, working the line between in and out.  Look over there: a sprawling electric band, chock-a-block with guitars. setting up free-form funk grooves.  Miles, circa ‘65-‘75 come back to life!

But a more careful listen to Spiritual Dimensions reveals that Smith—while surely aware of these Miles-ian precedents—is actually inverting them to brilliant effect.

The acoustic Golden Quintet features Vijay Iyer on piano, John Lindberg on bass, and both Don Moye and Pheeroan AkLaff on drums.  Recorded at the Vision Festival in New York in 2008, this set would appear to be the more conservative one.  And, yes, there are moments of fragile lyricism, such as the start of the second section of “Umar at the Dome of the Rock” where Smith’s muted trumpet echoes with aching melody over Iyer’s piano.  Yet only moments later, that expectation is dashed as Lindberg, AkLaff and Moye engage in a banging but brilliant free improvisation in which the roles of bass and drums are traded back and forth with rhythmic glee.  Or how about the full length of the acoustic group’s take on “South Central L.A. Kulture”, where Smith starts with a wah-wah statement for solo trumpet and then leads the band into a snaking funk jam, with Lindberg and drummers playing an ostinato bass groove that reeks of Bitches Brew and can only be described as NASTY.

You can tell that Smith knows what he is up to when the second disc—featuring the “Organic” band of four guitars, two bass players, AkLaff again on drums, and . . . a cello?—starts off with “South Central”.  And yet the version of this funk tune by Smith’s funk-oriented band sounds remarkably controlled.  Organic, refreshingly, is a funk band built on subtlety and pastels.  Smith introduces the tune with a fractured trumpet cadenza that ranges over the instrument, finally combining with cello in an exploration of texture.  When the groove enters—with no fewer than four guitars (including Brandon Ross and Nels Cline, by the way)—it is not a crunching affair but rather a sublime weaving of counter-melodies around the one.  Smith uses some electronic wah on his horn, but it feels less like madness than a way of descending into the bed of guitars that are moving, ballet-like, through the arrangement.

In short, Spiritual Dimensions removes the obvious distinctions between electronic and acoustic, funk and free, tonal and atonal.  The Golden Quintet plays more abstractly at times or with greater backbeat at times.  Organic, the electric band, often achieves a greater feeling of chamber intimacy.  Both groups work with long, multi-part compositional structures by Smith, creating a sense that the musicians are part of a great caravan that is covering lots of ground.  Even a relatively simple tune like the electric “Angela Davis” moves from a straight-on groove to a delicate devolution that generates a duo between the two bassists (Lindberg and Skuli Sverrisson) and then a unison declaration for open trumpet and cello.  These intriguing structures are just one of the things that make clear that Smith—despite self-consciously echoing both the trumpet sound of Miles Davis and the free-funk grooves of Davis’s rich 1970s period—is not merely a Davis revivalist.

Miles Davis, rather famously, doubted the artistry of avant-garde players.  And even though Davis’s bands played brilliant nearly-free music between 1965 and 1975, his own playing merely flirted with atonality around the edges.  His wholesale retreat from free forms after his 1981 comeback ended whatever thrill there was in hearing the most lyrical and incisive trumpeter in jazz history break beyond bebop harmony.

Wadada Leo Smith, however, has always been a melodist with a free-music core: a member of the AACM, a fellow traveler with Anthony Braxton and Leroy Jenkins, a student of ethnomusicology and author of abstract treatises.  While his music consistently refers to the sound palette of Miles Davis, his improvisations and note choices are bold and tart.  And on Spiritual Dimensions he surrounds himself with musicians who also dare to break free.

On the acoustic disc, pianist Vijay Iyer is the star.  Iyer is everywhere you turn in jazz these days, and his work here is bristling with invention.  His solos are restless and thrilling, and his dialogue with both Smith and the rhythm section is never less than daring.  But Lindberg commands an equally big sound, and the percussion team of AkLaff and Moye is well-matched.  That Iyer commands so much attention in a band of such maturity tells you that he is no flash in the pan.

The electric band is equally well-served by AkLaff, who sits at the center of things and directs traffic.  The guitarists may be hard to distinguish, but hurrahs to all of them for operating like fine threads in a large tapestry.  Cline is identifiable in many cases because of his angular melodic approach and penchant for eerie tones.  The cellist is Okkyung Lee, and she is deployed sparsely but brilliantly throughout.  The call to substitute cello for what would have been saxophone in a Miles Davis electric band is a perfect example of how Smith is both dedicated to Davis and utterly free of him.

Spiritual Dimensions arrived on my doorstep late in 2009, too late for consideration in creating those end-of-year “best of” lists.  Too bad.  Because it is.