Finland's Oranssi Pazuzu are a metal band in their own category. Since the appearance of Muukalainen Puhuu in 2009, they have brought a kitchen-sink approach to their music, and have somehow honed all that expansiveness -- from black metal to psych, from Krautrock to prog, from 1970s hard rock to post-industrial noise, from post-rock to ambient music and folk -- into an identifiable sound. This band's experimentation goes deep and wide on every recording. Värähtelijä is the band's first album in three years, and builds on the galaxy-spanning approach they took on 2013's Valonielu. "Saturaatio" opens the record with a ringing three-note guitar vamp from Jun-His and Moit and a rhythmic pulse provided by Ontto (bass), Korjak (drums), and Evill (synthesizers) that pulses like Suicide backed by Loop. And it only gets weirder. Jun-His' singing/screaming is surrounded by squalling electronic effects, an avant jazz, Larry Young-esque organ, and, later, a more tribal prog element that directly references another organ sound: Jon Lord's (Deep Purple). The title track is a moody, spacy jam, with shardlike chord vamps and snares playing like Neu! as whirring keyboards and Jun-His' growl offer some dark rumination. But this too morphs into something more abstract and cinematic. Black metal fans will appreciate the opening section of the 18-minute "Vasemman Käden Hierarkia," with its tremolo picking and occasional blastbeats, but five minutes in the entire track shifts again as layers of striated a cappella vocals, heavier, doomier guitars, and actually swinging drums build to explosion. Things get even stranger and more sinister throughout the long middle, as ambient space, drums, synths, and basslines court doom before fracturing. It's the demarcation point in the music that points to what Sin Nanna fronting Swans might sound like. "Havuluu" mercilessly (and relatively concisely) shoves together blackened death metal and prog before "Valveavaruus," the ten-plus minute closer, presents Oranssi Pazuzu at their most open and experimentally unhinged. Dark and humid ambient spaces surround folk instruments (the strings sound like electrified kotos) as reverbed percussion and mumbling, low growling vocals are delivered with a deliberate processional pace. It disintegrates before a more aggressive but no less ritualistic rhythmic attack blasts through, fueled by an organ playing the living hell out of a single chord and stretching it rhythmically and texturally until the whole band enters to carry it off into silence. Despite the truly mind-melting music on display here, the album has a downside: its suffocating mix. It is so compressed that it's sometimes difficult to pick out the more subtle individual elements and tones that were so carefully woven into the fabric of the music. It lacks Oranssi Pazuzu's natural presentation as displayed on Valonielu. But given how insane the music on Värähtelijä is, it's a notable but small complaint. For those willing to take this on its own terms, the payoff for listening is enormous.