Building a bridge between improvisation and ‘urban music’ has exercised several minds in the past two decades, presumably because of the tantalising idea of ‘hip-hop jazz’ rather than its all too often underwhelming reality. A solo over the sample du jour proved to be something of a dead end in the 1990s, but Lehman shows that there is still much to be gained from an intelligent and challenging exploration of the deeper aesthetics of art music and pop culture that were supposed to intermingle in the aforesaid hybrid. Picking up from where he left off on the quite brilliant 2009 set Travail, Transformation and Flow, the alto saxophonist and composer continues to devise music that appears to be a series of shifting, rotating geometrical shapes. Staccato horn motifs continually expand, contract, interlock and dislocate around a rhythmic base that is as dynamic as it is dense. The timbral contrast between the bell-like hiss of Chris Dingman's vibraphone and the bulbous roar of Jose Davila's tuba vividly symbolises the collision of delicacy and violence. Yet beyond all of the tightly mapped, grid-like scores, it is the way the brass and reeds evoke the echo chamber of a Scratch or Striker as much as they do a police siren that makes the point that the real route to the essence of hip hop is via the warp of dub and the weft of the big city's man-made soundtrack. This kind of teasing push and pull between organic and (apparently), synthetic sound appears throughout the set, and if Lehman's debt to the dot matrix precision of Steve Coleman's work is writ large then a no less important reference are the yearning, primeval eruptions of Arthur Blythe and Bob Stewart that preceded it. This is one of the reasons why, for all of the extremely intricate calculus of the music, it is not dry or bloodless. Rather than blending jazz and breakbeat-led forms, Lehman has channeled their DNA into a system of composition and improvisation with a singular strength of character.