Soundgarden is commemorating the 20th anniversary of the June 3rd release of Superunknown with two deluxe editions of the album, and also a vinyl version. The deluxe editions includes previously-unreleased rehearsal recordings, demos and b-sides. As a treat to the fans, the band has released a demo version of "Black Hole Sun."  It's streaming on the band's SoundCloud page now, and sounds like a rougher version of the original. Superunknown debuted at number one the week it was released in March  of '94 and is still Soundgarden's best-selling album.