Oswald took the lead. His alto sax was played upright and stationary as he sat and sent out a variety of long and bent and vertically rippling tones. At first guitarist Aldcroft mimicked Oswald — as did drummer Valdivia — but soon this talk-back grew into a complicating three-way dialogue.

Aldcroft's solo sections often had a dry, snapping rhythm (briefly think Derek Bailey), while at other times, he spoke out in thicker single lines and choppy tone clusters. As for Valdivia, the detailed finesse and flow of his stick and cymbal and traps and small gong work, contributed a flowing sound texture and a strong through line.

The trio's empathy — and its efforts to be in empathy — I found extremely attractive; but, of course, we're not talking about conventionally attractive here. We're talking about highly personal and highly creative instrumental sounds, even sounds we normally don't like.

The overall movement of this 45-minute set I later visualized as being like separate cloud formations that gradually accumulate, break apart, then slowly disappear into thin air ...

After Intermission, The Engines — the touring band from Chicago — definitely grabbed this audience with their approach to free music.

They played a hurtling, brave — yes, brave — and positive series of blues/R&B big city bass lines in these compositions, with the intersecting sounds of society, it seemed to me, stated in chants and anthems.

The four members always improvised compositionally and played clear thematic signposts and melodies before they creatively exploded and deconstructed them. In any case, the responsive listener was always given something to follow.

But — using "Mash Tone" as an example — this quartet really wasn't trying to be 'free' of anything — in fact, their compositions frequently had built-in solo interludes and group diminuendos that set the stage for bouts of simple old-fashioned, straight ahead swinging. Vibrationally speaking, it was an engaging mash-up of R&B/blues/jazz/noise into big city serious, stout-hearted and sophisticated tunes that were made for improvisation.

A big plus was that you could hear the heritage in trombonist Bishop's chaining bop-influenced scales; or admire Rempis' loud and clear alto as it spoke out over the narcotic churn of the third tune; or lean your ear into Tim Daisy's chatters smacks and steady driving tempos, as he eyeballed his rhythmic partner, Nate McBride, whose tensile bass lines articulated and anchored the hurrying music.

I thought The Engines got rightly applauded for their graspable approach to free music, but I also felt the guest trio of Oswald/Aldcroft/Valdivia made a good case for the 'non-idiomatic' approach to free improvisation.

Long live difference?

The Engines
Dave Rempis — saxophones
Jeb Bishop — trombone
Nate McBride — bass
Tim Daisy — drums

www.theengines.net