Metal Evolution

Headbangers, unite! It's a "Metal Evolution," courtesy of the same production team that made the 2005 documentary "Metal: A Headbanger's Journey. " One of those producers, Canadian anthropologist and filmmaker Sam Dunn, also is involved here as host of the 11-episode docu-series, which follows Dunn as he explores 40-plus years of heavy metal history by visiting bars, back alleys and the world's biggest open-air festivals. His road map is the family tree of metal genres -- shock rock, thrash, grunge, death metal, hard alternative, and so on -- that Dunn first created while making "Headbanger's Journey. " …