Story highlights Unreleased demos, comedy sketch among recordings to be included, reports say

Cobain died 21 years ago

(CNN) A compilation of never-before-heard audio recordings by Nirvana frontman Kurt Cobain now has a release date: November 6, the director of his film biography said.

The album will go on sale alongside the DVD release of "Montage of Heck," filmmaker Brett Morgen told Deadline's AwardsLine.

In reviewing Cobain's archives for the documentary, Morgen discovered "hours upon hours of never-before-heard Cobain music" and other materials, some of which will be included in the November 6 release.

Fans have been salivating over the prospect of new Cobain music since Morgen dropped news of the discovery in May.

He told AwardsLine he's still astonished the music hadn't gotten out in the 21 years since Cobain's 1994 suicide.