The title of Pan Sonic’s latest means strength or duration-an appropriate one for a four-CD set of all new material by two of electronic music’s most overwhelming practitioners. The Finnish duo has always operated at the extremes, oscillating between shudderingly high-impact electronics and spare, painstakingly precise compositions. For the first half of this impressive set, Pan Sonic’s teeth are fully bared, and you may wonder if you have the fortitude to weather the brutal intensity of the maelstrom. Once the duo’s artic, quiet side finally emerges, however, you’ll find yourself pining for further sonic catharsis.