The fifth album from Californian progressive metal band Isis finds them expanding on ground laid by previous releases. To stand still, to stagnate, is anathema to them. Each album has it's own aspect, their own facets to explore and this is particularly the case with Wavering Radiant. It is more focused than it's immediate predecessor In The Absence of Truth, but in the same instance adopts the desire to avoid classification that they have occupied throughout their career. These progressive tendencies are highlighted by Adam Jones, guitarist in Tool, following bandmate Justin Chancellor's guest appearance on ITAOT by lending his technical prowess to two tracks.There have been endless discussion over where to position Isis in terms of genre, but what is more important is their inclusive attitude to music. The character of Isis' music is largely indefinable; there is a precision to the songs, but it is not one of geometric exactitude. The churning, primordial walls of noise that characterised Oceanic and Panopticon have been replaced with a more ethereal and poised release, catharsis with melancholy acceptance, that that does not sacrifice emotional fortitude.Twenty seconds into "Hall of the Dead" the growing ambience is disturbed by buzzsaw guitars, but these are restrained. This restraint is symptomatic of the album as a whole; emotions are kept firmly in check, which allows them to provide brief interjections of anger and rage, which are all the more surprising and effective when they do interrupt the flow of the album. Aaron Turner alternates between a growl of painful (dis)articulation and clean vocals throughout, with the clean vocals sublimated in the mix to provide a sense of texture, the ghost of melody, rather than a focal point. "Ghost Key" continues the vein of exploration of rhythmic textures, anchored by Jeff Caxide's bass line. The song begins as an analysis of mood, nuance and tonal possibility, before being pounded by monolithic guitars. Album closer "Threshold of Transformation" is the song which most obviously pays its metal dues, but such is their ability to transform and transfigure their own material that after five minutes of complex riffery the simplicity of the Fender Rhodes break temporarily wrong foots you. This idea is then developed over the remaining four and a half minutes of the song, building to a crescendo before ending with Turner and Michael Gallagher's guitars gently guiding the song home in stately fashion.For their fifth studio album they decided to work with Joe Barresi and the clarity of his production work allows the instrumental passages to be fully realised. It is in these lengthy instrumental passages that the album finds it's disposition. These sections possess a tactile and hypnotic quality, with electronic synthesis playing a lager part in the overall sonic architecture than on previous releases. The title track, by some margin the shortest track on offer, is one minute and forty eight seconds of ambient electronica, with the sound rolling over the listener in undulating waves, gradually receding and folding in on itself before seamlessly seguing into "Song To Wake A Serpent". Wavering Radiant is less drone oriented, but Isis' music still inhabits certain characteristics of drone. Notes are isolated, manipulated, elongated, time is decelerated providing a temporal dislocation. The overall edifice is deeply layered, with complex time signature changes amidst the subtle organic/inorganic soundscapes and melodic chorus laden bass lines that interlink effortlessly with the guitars.Isis are on of the few contemporary pioneers amongst heavy music, not content to rely on metallisms or purely generic devices. In common with Tool, Mastodon and Sunn O))) they create a sense of malleability, and with Wavering Radiant they continue to expand the form and language of metal beyond the constrictions of orthodoxy without ever fully divorcing themselves from the genre. Audience expectations set the bar high for them, and they continue not to disappoint. 83%Isis on MySpace