On Sin After Sin, Judas Priest shed the thick, bluesy wallop of their first two records and embrace violently speeding metal. "Sinner” announces their tight new sound with twin guitars laying down interlocking riffs under Rob Halford’s infernal vocal acrobatics. They get even more aggressive on “Let Us Prey / Call for the Priest,” marrying blistering melodic runs with proto-speed-metal drum blasts, and “Dissident Aggressor,” which foreshadows the rise of extreme metal with its maelstrom of double kicks, breakneck time changes, and feral shrieks.