This young British two-tenor quartet may sport an enigmatic name (it's pronounced ‘orb’), and be inspired by Venn diagrams, in which data is sorted into groups that share characteristics and overlap, and those that don't; but there's nothing sternly scholarly about AuB. Tenorists Tom Barford and Alex Hitchcock, both high-flying Royal Academy alumni, formed the idea from writing differing composed parts separately, then jointly improvising on them sequentially and in overlaps – hence the Venn analogy.

The effects are sometimes robustly post-boppish, sometimes ambient, sometimes reminiscent of EST or Phronesis in hard-rocking climaxes – and Barford's and Hitchcock's close-listening compatibility is goaded throughout by the superb bass/drums partnership of Ferg Ireland and James Maddren. An insouciance with fiendish twists of timing is apparent from the off, with Ireland's proddingly arrhythmic bass intro against Maddren's jolting percussion on the opening ‘Not Jazz’ contrasting sharply with the theme's mix of stuttery and dreamily contrapuntal motifs. Hymnal pieces like the misty ‘Valencia’ mingle with almost-baroque two-sax counterpoint on ‘Dual Reality’, Barford and Hitchcock readily swap intimate dances and independently jazzy wilfulness, and the shifts between busily staccato grooving and deep-toned, thickly harmonised tenor melody on Barford's ‘Doggerland’ epitomises AuB's appeal. Synthesisers often add a missing chordal instrument, or shadow a sax solo with ghostly harmony, but their use is never less than musical in this engaging group.