There's a fine line in the post-punk instrumental world between mind-blowing musical ecstasy and, uh, whatever is playing underneath the guy who says, "Well, there's an app for that." It's a line the Scottish tracksuit wearers in the 'Wai have been toeing since they began, back when Brian Eno had just created the new Windows theme tune and it seemed there was at last a heavy antidote to the crimes of nü-metal. At their best, Mogwai replicate the sound of an advancing army of electric warriors, taking simple made-up-at-rehearsal riffs and drilling them into your cerebellum with staggered replication and ante-upped distorto levels. The cumulative effect can be like listening to a church choir doing canons while simultaneously crushing OCs on your bicuspids, one at a bloody time. On their latest - which sees the band reunited with Paul Savage, knob twiddler on their '97 debut, Young Team - the quieter moments are even quieter than usual, as on the Air-y "Letters to the Metro," and the decibel tests are as gnarly as ever, with the mind-squashing moments of standout "Rano Pano" and closer "You're Lionel Ritchie" duplicating the sound of gladiator shields clashing in your ear.