The 13th Choir is a visit to heavy metal before hair bands, Metallica and grindcore. Songs with structured riffs, slightly distant vocals and dark chord progressions abound. Joel Conley is the vocalist and guitar player — the “jezebel of decibels,” so to speak. Andy Morrow handles the lead-guitar riffing attack. The percussion and repercussion are handled by Amy Ugstad, who casually pounds out complex, almost tribal drumming patterns. Bass is played steady and solid by Mark “Thunder Donkey” Swanson.