THE ROCK WORLD has witnessed many psychedelic revivalists, but while acts such as Tame Impala and Temples replicate sounds from the past, Unknown Mortal Orchestra exist on their own wavelength. There are obvious nods to Pink Floyd and Captain Beefheart, but they're offset by chunky hip hop beats and weird, perambulating melodies relayed through singer Ruban Nielson's soulful falsetto and smothered in reverb. The result is alien but strangely comforting, like a weird, untitled mixtape you found in a second-hand car and became besotted with. Fittingly, the back story for this New Zealand band is far from straightforward. After the acrimonious break-up of exuberant Auckland noise-rockers The Mint Chicks, in which he performed with his brother Kody, Nielson felt burnt out. He was living with his wife and two young children in Portland, Oregon, where they stayed for a time in a yurt. In 2010, he anonymously uploaded a home-recorded track called Ffunny Ffrends to Bandcamp under the name Unknown Mortal Orchestra. A self-titled album followed, then the formation of a band with Portland natives Jake Portrait on bass and drummer Riley Geare. They are in the middle of a lengthy tour - dropping into Hong Kong on January 21 - that has seen their precise psych-pop stretch into something looser and more hypnotic. There's a change in Nielson, too: wide-eyed and softly spoken in conversation, he develops a swagger when performing, careering wildly around the stage with his guitar. "The person I am onstage is the person I'm being when I make my wife laugh in the kitchen, when I'm at my most comfortable. When you're onstage it seems so simple," he says. Yet Nielson is mindful of the potential for what he calls "soul sickness", the stew of loneliness, alienation and "spiritual, mental and physical exhaustion" that comes with extensive touring. It's a point underlined by the band's first tour in 2011, an 18-month odyssey when the band's motto was "say yes to everything", and during which they lost two drummers to exhaustion. A second album, II , released earlier this year, is a document of that period. On it, Nielson sings wistfully about wanting to "swim and sleep like a shark does … asleep and constantly floating away" and about being "so tired but I can never lay down my head". There's a fuzzy nocturnality hanging over II , capturing that wild combination of energy and exhaustion that can accompany insomnia. "It's kind of out of focus. I wanted it to feel like that when you listened to it. I'd bounce tracks through lots of tape recorders and wear them down. Recording guitar into a computer is pure sanity and clarity. Every time I removed it sonically from that point, it felt like it was becoming more tired or intoxicated." Exhaustion was the powering force behind the sound of II , while an interest in the occult was its guiding image; the album sleeve depicts neopagan expert Janet Farrar brandishing a sword on a hilltop. "If people talk about magic and stuff it sounds kind of silly. But at the same time the idea that something is ancient and mystical doesn't really lose its appeal because you stop being superstitious. I think that the occult at least has the idea that there are less rational ways of doing things that are still relevant." Ruban says all of his alternative working methods - the twilight tinkering, tape experiments, witches and wizards - have one thing in common: they come from a part of his brain which he can't control. "It feels like I'm backing towards some kind of destiny," he says. "I don't do any planning. I just try and let things bubble up like they do in a dream." Guardian News & Media Unknown Mortal Orchestra, January 21, 8pm, Grappa's Cellar, B/F Jardine House, 1 Connaught Place, Central, HK$300. Inquiries: untitled.asia