Somewhere between My Bloody Valentine and Sunn O))) lies Pyramids, but where that is exactly remains to be seen. The Hydra Head rebels vacillate from waves of lush distortion on "Sleds" to angelic chorals and dark industrial stomps on "Igloo" and "End Resolve," without serious injury or impact. Their cinematic epics are open-ended experiments that bury structure in exposition, which is to say they scored par for challenging music's course. Yet even the gorgeous atmospherics of "The Echo of Something Lovely" tend to be broken down by machine-gun drums. In the end, Pyramids is in on everything, and you're often left outside waiting to get in.