It was pretty much a year ago that Scar Symmetry announced the replacement for the departed vocal talents of Christian Älvestam. Many people saw the need to hire two new singers as an under-whelming compensation to the loss of Älvestam's two voices, which contributed much to the signature sound of the band. But this will be a decision that pays off, especially after the release of Dark Matter Dimensions.

Vocals are indeed the focal point of Scar Symmetry's fourth album, perhaps even more so than 2008's Holographic Universe. Rallying between the rampant raised-eyebrow growls of Roberth Karlson (Facebreaker ex-Edge of Sanity) and the soulful power-prog clarity of the lesser-know Lars Palmqvist (Last Temptation), the two newbies share an almost melodic death metal Sonny and Cher vibe. Imagine “I Got You Babe,” with savage roaring and space-tech vocabulary.

“Noumenon and Phenomenon” is one of the band's most infectious songs to date, playing on the tag team vocal dynamics strongly, with a huge pre-chorus and a huger chorus that would give a chart smash hit a run for its dirty money. Whilst monster melodies have always played an important part in previous albums, Dark Matter Dimensions' biggest critical bullseye will be the poppy nature of many of the choruses. It would be hard for Simon Cowell himself not to flick a greedy grin at some parts of “The Consciousness Eaters.” But as perfect as some of the lines would be for an awful Irish boy band to mime over a ballad backing-track from hell, Scar Symmetry have unsurprisingly decided to lay them over a wall of astronomical metal, backed into a corner by down-tuned blasphemy and cardiac kick drums, until they explode in tuneful triumph. Seriously, some of these tunes are brilliant and will warrant multiple re-repeats. “Non-Human Era” is a particularly engrossing cross section of aggression, cyber-groove and car-stereo karaoke.

The riff magic of the first two albums, disappointingly, stays relatively unattainable, as much of the guitar is left to support the main cast with chord progressions or the sporadic plectrummed rev of a malfunctioning mechanism. Search thoroughly enough though and you should discover enough lower-fret creativity, from the wandering riff in “Mechanical Soul Cybernetics” to the mean rhythm chops on the title track. On occasion, the whole affair does get wearingly Fear Factory, but there is no shortage of excitement when Per Nilsson and Jonas Kjellgren break their leashes, to bust out those sweeping leads.

The band's sound is still there in full glory, and the vocal expansions for Dark Matter Dimensions hasn't actually compromised that at all. Casual followers of the band will struggle to notice any change, whilst it will almost certainly procure a mixed reaction from the denser fan base. At this point, I can only encourage those who can't deal without Älvestam behind the microphone to stubbornly feed on the new Miseration album; or just do yourself a favor and wait to see these new songs in the flesh.

If live vocal arrangements were ever becoming a problem for Scar Symmetry - and they were - fear no more. With the necessary man power on stage, these unfolding tracks of all encompassing grandeur and vocal layerdom will reign supreme, becoming nothing short of an observed phenomenon.