If there’s one thing Glenn Kotche’s intricate work as drummer for Wilco proves, it’s that the man likes his noise. Disparate sounds, space, silence, atmosphere—Kotche knows well how to deal in these eccentricities and deliver them with subtlety. In his work with Darin Gray as On Fillmore, that subtle touch with noisy expansion is on display, and Extended Vacation may be the duo’s most expansive, spacious record to date.

And within all that space is a cool, dark mood. The title, as it turns out, has very little to do with leaving something behind and much more to do with exploring the unknown. And these stretched-out compositions have a reticent wonder to them, as a tense, quiet mood settles over vibraphone and bass, over light but effective waves of percussion.

The best parts here wash over you and pull you into the album’s searching. “Master Moon” has a lullaby melody to it, but underneath Kotche’s percussion shuffles and rattles, it builds and subsides and, as if the two were wandering too deep into a jungle, the song ups the worry and sustains that whirring tension throughout. “Complications” starts and stops on itself, shimmering with haze before running itself down into a nice dissonance.

The albums two biggest songs, “Daydreaming So Early” and the title track, go a long way in showing off the album’s strengths. But they also highlight its weaknesses in the process. “Extended Vacation” shows Gray laying down a buzzing, jazzed-up bass line over which piano ambles and Kotche’s drumming piles up on itself. It’s as unmoored as the album is, but it works by employing grinding distortion and feedback that shifts the dreamy feel of the album into something more nightmare-ish. “Daydreaming So Early”, on the other hand, falls apart because it overplays its hand. The duo seem like they want to break the even repetition of the album, but do so by layering animal sounds over the track. The first ones, of far off birds, aren’t bad, but they start to multiply and rise up higher in the mix, and the whole thing becomes distraction, more like a nature sounds disc than a piece of compelling music.

But the thought to mix up the feel, though botched there, is the right one. Because as compelling as the dreamy feel of this record can be, there’s little in the way of variation. Extended Vacation establishes itself well, creates a world both mysterious and inviting, but once you’re in the world its borders show themselves, and there’s little in the way of surprise. There’s something to be said for the moody quiet they deftly establish here, but for all the searching On Fillmore does on this record, when they come back into the light, it turns out the dark didn’t hide as many treasures as they’d hoped.

• "Master Moon" MP3