Departure of Reason, the fourth collaboration between New York guitarist Mary Halvorson and violist Jessica Pavone, frustrates any effort to pin it down. If you want it to be a bunch of freeform guitar noise and pedal effects (I sort of do), Halvorson and Pavone confound you by framing such moments with simply constructed melodies. If you’d prefer a lovely madrigal-folk record to play at a dinner party, the women will string you along only so far before busting out some badass power chords and slippery detuned squiggles. And if you note their association with NYC’s avant-garde and reason, “Well, THIS will keep me awake on my car trip”, think again. I say this as a public service.

Not that it’s boring, exactly—a careful listen through headphones reveals a wealth of cool stuff happening, mostly in the guitar but also in Pavone’s viola. Pavone spins out modestly attractive melodies with a rich tone, and she makes them sing using subtle effects. She’ll screw with her perfect intonation like a blues singer; she alters her timbre to make tunes pop out of the musical texture, or to create textures that sound muddy and scary. Near the end of the short track “Onslaught”, Pavone somehow juxtaposes two bowed figures, a quick ostinato, and a longer three-note descant. Her playing is impressively forthright.

Halvorson is the flashier player, jumping among the sounds and techniques her electric guitar will allow. There’s a moment in the song “Begin Again” where she gets two distinct tone colors to melt down against one another contrapuntally, a moment that elicited the truest aesthetic response in my notes: “WTF HOW IS SHE DOING THIS”. Halvorson has several other “How is she doing this” moments here, like the middle of “New October”, where she jumps from a power-chord/ostinato onslaught—more counterpoint!—to a sort of dry chime that blends seamlessly with Pavone’s pizzicato. She also uses plenty of that Halvorson trademark, an abrupt slide into wobbly semi-tonality that’s nauseating in the best possible way.

Honestly, if you spent the next year seeking out the complete discographies of Halvorson and Pavone, you’d probably lead a very rich and rewarding life. That said, Departure of Reason feels like a minor work, its creators trying something they haven’t fully realized yet. The songs alternate simple tunes with the sorts of cool effects described above, and the tunes aren’t much—they’re overly simple and hamfisted, expedient melodic frameworks for the stuff the women really want to play. The music seems bipolar and unintegrated. It switches between moods when you want it to flow, presents its disparate ideas for consideration when you want those ideas to sweep you up and carry you along to the next ones.

Frustrations aside, Departure of Reason is still an opportunity to hear two exciting instrumentalists adding to their bodies of work. (They also sing on three songs, but that’s not what you pay to hear.) It’s an album that forces you to focus on its subtleties, which are mostly worth the effort.