Those looking for something less than banal to explain the perpetual imminence of a fifth Massive Attack album will be disappointed. The delay neither involves the kind of acrimony that shaved the original trio down to Robert Del Naja (aka 3D) nor charges of child pornography, like those heaped on Del Naja in 2003. In fact, Del Naja is now happily rejoined by fellow founding member Grant “Daddy G” Marshall, who, following Andrew “Mushroom” Vowles, departed the outfit in 2001 due to creative differences. Rather, the hold-up is a consequence of Massive Attack’s inherent perfectionism, a trait that has only become more urgent for the group once anointed as a brilliant production unit that, for better or worse, put Bristol on tastemakers’ agendas and the words “trip-hop” on their lips.

Indeed, the question of where the group ought to tread next is not one the band takes lightly. After all, there is no wish for them to dissolve into the kind of self-imposed oblivion that came when they spawned myriad copy-cat trip-hop bands in the ‘90s. Mezzanine (1998) struck down the wave of mimicry by casting the group’s signature ethereality into howling darkness with a rawer, guitar-driven sound. That album also signalled the group’s intention to become a live band and, to the bitter chagrin of Vowles, Del Naja’s affinity with post-punk and psych-rock.

Just as Protection (1994) reinforced the dub-inflected industrial grooves of debut album Blue Lines (1991), 100th Window (2003), a joint effort between Del Naja and longstanding Attack producer Neil Davidge, cemented Massive Attack’s brooding mien. That Splitting the Atom—the EP leading up to the release of the tentatively-titled “LP5” possibly early next year—sounds little like what they’ve done before is unsurprising. It is also most certainly welcome, as 100th Window was headed for its own darkly oppressive cul de sac. However, insofar as the four-track offering is representative of the full-length outing, it will hardly mollify fans for which a semblance of a Massive Attack “sound” is vital.

Boasting collaborators like Damon Albarn, Elbow’s Guy Garvey, TV on the Radio’s Tunde Adebimpe, as well as long-standing team player Horace Andy, the EP is little more than the proverbial sum of each collaborator’s efforts. The effect, then, is as if Massive Attack have taken a backseat, lending their production skills to their guests rather than the latter submitting their talents to illuminate the pair’s work. “Splitting the Atom”, for instance, is an unimpressive dirge-like number that sounds like a Gorillaz take on a mafia soundtrack, what with its lulling tinny beat, dampened organ backing, and a Leonard Cohen impersonation by an unidentified someone. The curious choice of Andy to fill the chorus is misguided, as his famous warble is so muted as to be the aural equivalent of having his wings clipped.

“Pray for Rain”, the EP’s best track, effects a bone-chilling discordance with Adebimpe’s hushed and disaffected delivery. Save for the shimmery synths a la Simian Mobile Disco that appear halfway, though, the song could be an outtake for the finale of TV on the Radio’s Return to Cookie Mountain. Yet it is the only track that displays Massive Attack’s knack for executing a mood of singularity without compromising sonic layering.

Meanwhile, “Psyche”, which appears here as a remix by Fever Ray producers Van Rivers and the Subliminal Kid, features British vocalist Martina Topley-Bird, who appositely masters Fever Ray vocalist Karin Dreijer’s pitch-shifting to a T. But once again, other than it sounding like a barbiturate dissolving in the membrane, there is little evidence that Massive Attack have so much as breathed on this track. Final song “Bulletproof Love”, also a remix, unexpectedly contorts Guy Garvey’s normally emotive and expansive tenor into something sinister that appears to emanate from a tiny crack in the wall. Standing guard is an authoritarian rumble of sub-bass and spasmodic ricocheting effects—the song’s only familiar Massive Attack threads.

Far from being the band that every other band wants to sound like, this compilation-style EP suggests that Massive Attack are indiscriminately mining for something to make their own in a climate that has shifted in favour of producers like Albarn and just about anyone who can fashion bleeping synthscapes. Yet, like a movie that’s so unhinged that all one wants to know is whether it will end convincingly, the seeming lack of bearing about Splitting the Atom only serves to thicken the wall of suspense surrounding album No. 5.