Grails is not for the attention deficient or the song-oriented. The Portland instrumental rock quartet’s seventh studio album, Deep Politics (Temporary Residence Limited), contains eight tracks, but no lyrics and no traditional songs. Instead, the album consists of rising and falling tension using percussion, guitar, strings, pan pipes, bass and miscellaneous effects, layering complexity upon complexity until the intricacies spill over into what is usually a guitar riff.

Unlike the most obvious touchstone to Grails’ sound, Deep Politics does not have the impassioned urgency or the startling dynamics of a certain Canadian nine-piece outfit. The album flows like a meandering river, with a calm exterior that belies an undercurrent. But this is less the Amazon than the Orinoco; Grails just does not produce enough tension or anxiety to keep the music from rising above “intricate.” At times the guitar is broad and anthemic, the strings are triumphant and the drums are propulsive, but the mood never changes above a certain bemused studiousness. The dynamics are relatively stable; the album is the constant chug of a warship on calm seas.

Take the eight-minute track “Almost Grew My Hair.” It enters with a strummed acoustic guitar line, accompanied by disembodied moans and electric guitars, which play interlocking parts. When the drums enter, the song achieves the dynamics of a slow groove, led by the electric guitars. Another acoustic guitar enters and plays a solo, and the song slowly rises, with more and more electric and acoustic guitars being piled onto the underlying groove. Halfway through, the bottom drops out for a moment before the groove returns in a different form. The track becomes a sprawling piece of mellowness that no amount of distorted guitars can overcome, and it becomes unclear if Grails intends to go anywhere with it—at least until the searing guitar solo.

Deep Politics is interesting music, but whether it is compelling music depends on what you want out of it. The music achieves a throbbing equilibrium halfway through each track, which makes it easy to zone out. So maybe this is just great zone-out music.