Fiery Furnaces’ Friedberger sibs are monsters of rock. And it’s genuinely tough not to admire Eleanor and Matt Friedberger’s crazily prolific music-making and live intensity -- ideas seem to simply shoot off the Brooklyn, N.Y., sister-brother team like sparks. Astonishing to think the two have only been making music in the public eye since 2000.

I’m Going Away (Thrill Jockey) is their eighth album, not counting side and solo projects -- a factoid that should make Axl Rose and other indulgent dinos blush. Of course, there are real downsides to FF's overwhelming cornucopia of sound: it can be a rigorous exercise in careful listening to make out Eleanor’s motor-mouthed vocals, and it can be hard to piece apart the albums. At moments they might be viewed as simply movements in one long, multi-album song cycle.

I’m Going Away, in fact, appears to pick up where FF's last studio full-length Widow City, left off: with '70s AOR jukebox reminiscences, as well as nods to the Tin Pan Alley songcraft of granny’s era (the Friedbergers paid direct tribute to grandmother Olga Sarantos with 2005's Rehearsing My Choir). The album's only non-original, the title track, is given the rough and tumble Fiery Furnaces’ ADD treatment: it’s jumped up, sped up, and frenetic with the band's archetypal hardcore-meets-post-rock urgency. The Friedbergers are getting their kicks juxtaposing their breathless abandon and breakneck virtuosity with the old-fashioned and throwback when it comes to numbers like “Take Me Round Again,” a jaunty romp that old-timey warblers would be perfectly happy to croon.

That stop-and-start strategy finds its most startling form with “Drive to Dallas,” a leisurely soul workout that tears out with the group's trademark restlessness and then settles into a sweet groove that bleeds into “The End Is Near.” I'm Going Away abounds with sweet, loping pop numbers like "Cut the Cake," the type that Lou Reed might have penned in his early years as a solo artist. "Even in the Rain" shimmies with shambling blues-rock riffs and roadhouse piano that Exile on Main Street-period Stones might appreciate, though it stubbornly refuses to succumb to the lure of the guitar solo. All and all, in the process of working with longtime collaborators, drummer Robert D’Amico and engineer-bassist Jason Loewenstein, Fiery Furnaces seem to finding a new rhythm and taking it easy -- even as they promise to maintain a manic creative schedule with the release of a “Democ-Rock” limited-edition vinyl box set and “silent record” book. Going away? No way.