After the single "Born Slippy" hoisted them into the mainstream, Underworld's approach seemed to be ever more tightly focused on becoming an unstoppable stadium-techno juggernaut, their former quirks and subtleties pounded to dust by the stampeding riffs. It's a relief, then, to report that A Hundred Days Off is the most varied and intriguing set they've made since the groundbreaking dubnobasswithmyheadman. The usual monster-truck grooves still constitute the bulk of the album, and tracks such as "Dinosaur Adventure 3D" and "Two Months Off" will doubtless lay waste to dancefloors for months to come; but they're interspersed here with more restrained pieces, such as the ruminative ECM-style post-rock guitar instrumental "Ess Gee" and the laid-back breakbeat country-blues cut "Trim", which proceeds in the relaxed manner of JJ Cale. The classic Underworld mode of slow flux over a long period applies to most tracks, but this time the outcomes are less predictable, particularly in "Little Speaker", in which the initial piano vamp and loose, liquid bass groove blossoms over eight minutes into a minimalist keyboard piece that recalls the work of Steve Reich and John Adams. Karl Hyde's found-phrase lyrics are as ambiguous as ever – especially his murmurs in "Sola Sistim" about "your fingers, broken... beautiful... " – although some of his singing loses definition in the more headlong grooves. Ironically, his clearest vocal melody, to the opening track, "Mo Move", resembles that of Röyksopp's "Poor Leno", which is rather like techno chasing its tail. Though it's none the worse for that.