The piano echoes the modular synthesizer, or perhaps it’s the other way around. Either way, there’s a vapor trail of synthetic noise that hovers about, that emanates from, the roiling piano in the third part of a “Piano/Modular Synth Improvisation” by San Francisco musician Clarke Robinson. And then, just as a certain hierarchy seems to present itself, the synthesizer presents its own not insignificant flurry of sonic gusto, a brash field of constrained chaos. This play back and forth between modular and piano, between abstract and traditional, between amorphous and familiar, is the core of Robinson’s work here, in which the elements, so distinct from each other, are allowed to circle each other, to serve varying roles: shadow, peer, guidepost, antagonist. Bracing stuff.