Like their Elephant 6 labelmates and kindred spirits Olivia Tremor Control’s Music From the Unrealized Film Script, Dusk at Cubist Castle,Neutral Milk Hotel’sdebut, On Avery Island, is an inscrutable concept album, a chronicle of an insular world told in a remarkably universal language. A fuzzy masterpiece of experimental lo-fi recording, the album wraps its ragged pop songs in ribbons of loops, marching-band squawks, and Casio noodling; the opener, “Song Against Sex,” is as much a manifesto as a kickoff, a self-propelled marvel hopped up on rapid-fire wordplay and a stunningly ramshackle melody punctuated by bloated trombone moans. Throughout the record, Jeff Mangum’s wheels threaten to fly off at any time — his songs are cryptic and crazed, his ideas fast and furious, and together they force the home-recording concept out of the basement and into a brave new world.