NEW YORK (Billboard) -- As it prepares for its maiden tour of South America, which begins November 22 in Santiago, Chile, Pearl Jam is still working on its first studio album since 2002's "Riot Act."The as-yet-untitled set is due next spring via Sony BMG's J Records label."It's been a difficult record and it's like sometimes the harder something is, then the more valuable it becomes," frontman Eddie Vedder said during a Brazilian radio interview earlier this week."It's easily the best stuff we've done but also some of the hardest stuff. It's very aggressive, because again, it's kind of a product of what it's like to be an American these days. It's pretty aggressive, especially when you turn it loud."The band has been working on and off throughout the year on the set, but Vedder said, "It's not quite done. I'm hoping to finish the last of the songs while I'm down (in South America). I'm bringing my tape machines and all that down. If I can come back and finish the last few songs in January, then it will be out in April or something."For now, Pearl Jam is not planning to unveil any new songs in a live setting. "We want them to be heard for the first time when the record comes out," Vedder said.But he added he had been mulling an album title that was a play on Soundgarden's "Superunknown": "I was thinking of the word 'un-owned' -- not owned by anybody," he said. "The sky is un-owned. The moon is un-owned. We're un-owned. We want to remain un-owned. The title was 'Superun-owned.' "Continuing an initiative launched during Pearl Jam's recent fall North American tour, the South American shows will be available for paid download from the band's Web site (http://www.pearljam.com) within hours of their completion.Copyright 2005 Reuters. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed.