Now listening: Colin Stetson and Sarah Neufeld, Greg Haines

Some pieces are so moving and so mysterious that you can keep coming back to them for years, continually finding new sustenance without ever finding complete answers. For me, two such pieces are “And Still They Move” (2015) by Colin Stetson and Sarah Neufeld, and “So It Goes” (2013) by Greg Haines.

The mystery is part of the appeal. “And Still They Move” brings the listener into a world of dark, undulating sounds layering upon each other, bending around each other, butting up against each other harmonically, all the while moving at a measured 4/4 pace as a quiet disturbance — not loud enough to be a rumble, but rumble-like in its timbre — enters and recedes.

The rumble is easy enough to identify — it’s Stetson’s breath moving through one of his many reed instruments, and sometimes making an audible vibration. But other sounds remain mysterious. Sure, there might be an interview somewhere in which saxophonist Stetson and violinist Neufeld break it all down, but there’s something enriching about listening, over and over, and asking yourself: Is that a bass saxophone or a baritone saxophone? Are there vocals in there? How many tracks of violin am I hearing? Is there a keyboard in the mix, or is that all natural instrumentation? I might never know for sure, and that’s one of the reasons I’ll keep coming back.

Greg Haines’ “So It Goes” has a similarly powerful hold on my musical imagination. A distant percussive sound underpins a slowly unfolding drone. Subtle bubble-like bleeps pop. An electronic sound of indiscernible origin oscillates. A thick wall of drone builds and builds as a three-note motif develops alongside it, with the motif returning to the first note for the fourth note of each phrase and the wall of drone incorporating new sounds, overtones and bits of distortion as it pushes relentlessly forward.

Then, as if that relentless push has gotten us where we needed to go, we’re back to a quiet sonic palette of synth beds and fading bleeps, wondering what it is we’ve just been through — and wanting to go back through it.