Mac Rebbenack is back and he’s got company. Dan Auerbach of band of the moment The Black Keys sought out the 71-year-old Dr John and offered his production services and the result is a meeting of minds wherein the young disciple is having as much fun as the old master. Seeped in reverb and the musical mythology of the Big Easy, locked down it ain’t – the music jerks and rolls to fractured blues guitar, rattling drums, prime cuts of brass and the curative gospel harmonies of the beatific McCrary Sisters. Thematically that title might make more sense as Dr John prowls his adopted hometown leaving no rock unturned in his hunt for the folk on the hill who fiddled the economy while New Orelans drowned and like Springsteen’s latest, Locked Down burns with a gnarled righteousness. On Revolution he laments “Dumb moves of money left us in a desperate hour/Economy conning me out of my sanity” while on the apocalyptic, organ-grind of Ice Age he avers “KKK, CIA all playing in the same cage”. Cleansing voodoo alright. You’d do well to follow doctor’s orders.