Marking public enemy’s 15-year journey from the pinnacle of the rap game to a less populist but still vital position as fractious elder statesmen and industry-baiting online evangelists, Revolverlution is part-skewed retrospective and part-flawed experiment.

The smattering of muddy live tracks, sampled phone calls and earnest messages about staying in school are low points for these hip hop pioneers who once constructed albums with surgical precision. Musically, new cuts such as “Put It Up” and the title track itself draw on the same simmering cauldron of ’70s funk, bass-heavy grooves, declamatory rhetoric and impolite guitars which have dominated PE’s work since the mid-’90s. The grinding “Son Of A Bush” takes a none-too-subtle sledgehammer to Dubya (“Son of a bitch! Son of a bad man!”) while Flavor Flav does his obligatory bendy-legged Jim Carrey routine on “Can A Woman Make A Man Lose His Mind?” and Professor Griff auditions for Rage Against The Machine with “What Good Is A Bomb?”.

A more revolutionary aspect of the album is its remixes of classic PE cuts, downloaded from the band’s website and overhauled by novice studio contenders across the globe. Thus Scattershot’s “B Side Wins Again” emerges as a splice’n’dice noise salad, Vienna’s Functionist sculpts “Shut ‘Em Down” into a trip hop juggernaut, Argentina’s Jeronimo Punx slather “Public Enemy No 1” in ragged lo-fi Beastie beats, and so on. Energy levels are high, and the egalitarian concept borders on radical.

Chuck D’s righteous rapier rage and piledriver propulsion may have slackened, but in terms of challenging lazy music business norms with brutally eloquent, anti-authority cyber-funk, PE are still fighting the powers that be.