Gone are the days when female vocalists are obliged to define their sound as "pretty." Janis Joplin enabled a sound both harsh and pained; Courtney Love, a dead girl snarl; Björk, a full-bodied Icelandic yodel. Breaking out of the "pretty" standard has become the norm in non-mainstream music circles. Ironically enough, the challenge now is how to reinvent the "pretty" vocal in a way that is novel and compelling. At first listen, the stoic multi-part harmonies of School of Seven Bells' siblings, Alejandra and Claudia Deheza, are jarringly poignant. Perhaps "pretty" isn't dead.

Formed in 2007, School of Seven Bells features former Secret Machines' guitarist Benjamin Curtis and the Deheza twins of On! Air! Library! Named after a fictitious South American pickpocket school, the trio melds the surreality of dream-pop with the wooziness of contemporary psychodelia. Their debut, Alpinisms, pairs electro-infused drone with a pop sensibility; add the twins' unwavering angelic harmonies and the album glows.

Spacey, ambient, and vaguely tribal, Alpinisms creates a landscape to get lost in. Despite their differing musical backgrounds, the band has a cohesive sound. Similar to the midrange vocalists of Jem and Azure Ray, Seven Bells brings airy authoritativeness even in falsetto. The album opens with the liturgical "lamundernodisguise" and easily transitions to the eerie "Wired For Light," a track that operates on equally striking ominous dissonance. Later, mysticism meets technology on the sonar-like pulse of "Prince of Peace," but not before the 11-minute "Sempiternal/Amaranth" offers a minimalist start that builds to muddled mash of sound. Somewhat disappointing is the auto-tune processed "Chain"; its robotic effect unnecessarily distracts from an otherwise organic feel.

Alpinisms is a sensory experience, like downing a few tumblers of foreign liquor: too much will leave you lightheaded. Then again, everything is a better with a buzz.