Sponsored by Elixir® Strings: The phrase ‘diatonic dissonance’ might be intimidating, but it’s a common sound in 1970s progressive rock. Characterized by a tension between notes, dissonance sounds particularly ‘other worldly’ when played on a 12-string guitar, as Elixir® Strings artist and educator Shawn Persinger demonstrates here. Playing chord progressions reminiscent of prog rock giants Rush, ELP…