WHAT WE have here are two prime specimens of Metallicus Mutatus, a creature indigenous to North America and as resistant to extinction as the cockroach.

RATM you know well: full-bore rap-metal activists roaring-red with a righteous indignation last heard on Fear Of A Black Planet. But whatever about Chuck D and crew’s Farrakhan-isms, their sound sources were always brain-bogglingly catholic, while Zack de la Rocha’s lot adhere to sonic policies as hardline conservative as their politics are leftist.

Never mind that short-lived double-headed tour with Wu Tang Clan a couple of years back, on record the band remain technophobic to the core. Check out the proud proclamation on the sleeve: “All sounds made by guitar, bass, drums and vocals”. But frankly my dears, who gives a damn? The studio is there to be abused, and such Luddite tendencies strike this listener as dogmatic to the point of blinkered.

All the same, you have to hand it to guitarist Tom Morello – the guy can squeeze some wild noises out of that Fender, particularly his patented scratch-mix flick-the-pick-up-switch technique. And occasionally (as in ‘Calm Like A Bomb’, ‘Ashes In The Fall’ or ‘Maria’) he suggests some Black Rock Coalition firebrand (in livid colour?), possessed by Jimi but still keeping one ear cocked to Terminator X.

So, like it or lump it, Rage’s guitarist is their focal point, and the other three rarely deviate from turf comandeered on their eponymous debut a full six years ago. Rhythm section Y.Tim.K and Brad Wilks remain strong but stolidly stuck in third gear, while de la Rocha still spits agitprop polemic over mallet-handed grooves tailored for the festival moshpit.

When the band do scramble the formula a little, as on the swaggering ‘Mic Check’ or the folky undertones of ‘Born Of A Broken Man’, the extra investment is repaid threefold. But too often they merely describe rather than prescribe (“A mass of hands press on the market window/Ghosts of progress/Dressed in slow death”). We know they’re serious as cancer, now what about a cure? (And pardon me for asking, but what does RATM’s anti-establishment posturing count for when Morello will use his powerchords to endorse a heap of Hollywood dogshit like Godzilla?)

To revisit the Public Enemy analogy then, if the Rage represent Chuck The Angry Prophet, then Primus play Flavor Flav, the connection being that Tom Morello plays on and produces a brace of the tracks on Antipop (alongside Stewart Copeland and Tom Waits).

And, yea verily, it’s a frayed tightrope that Primus tread. At best, the trio come on like a wonderfully Cronenbergian splicing of The Mothers, Beefheart and early Faith No More; the CatDog of hard rock (“We don’t use the term freak, we prefer bi-cranial quadruped”). But on a bad day, they’re woefully unfunny: Weird Al Yankovich with Chili Peppers chops.

Still, full marks for idiosyncracy. Antipop is a loud catalogue of Zappa-esque grotesques like ‘Lacquer Head’ (glue sniffing freak puts himself in a coma), ‘Natural Joe’ (mellow-headed bean curd guzzler gets hopped up on sheep dip and porn videos) or ‘Dirty Drowning Man’ (“I lick electric fence/I put barbed wire in my pants/And do a Celtic dance”). But the faultline that undermines this record can be most clearly observed in tunes such as the opening ‘Electric Uncle Sam’, which takes the royal piss out of US supremacy, but is failed by a backing track which flounders like The Offspring.

So, the premise is great, but hot an’ all as Lee Claypool, Larry Lalonde and Brain are in funk-metal music theory, those ideas sometimes land them one byte away from Limp Bizkit. Antipop is slick and smart, but it’s got no heart.