Is the world ready for a love song from a stubbornly prog band like the Mars Volta? And shortened from its intended time frame of 7:20 to a radio-ready 4:50, no less? No, this isn't an impending sign of the Apocalypse, but rather the first taste of what frontman Cedric Bixler-Zavala considers to be his Grammy Award-winning band's "version of an acoustic album" with the June 23 release of "Octahedron," the Mars Volta's fifth and potentially most commercially viable recording to date. Principles Bixler-Zavala and longtime partner and guitar wizard Omar Rodriguez-Lopez trade in their usual calculus-based Latino jazz punk for the kind of heartfelt sentiments most successful progressive rock bands end up wading toward at some point in their careers. A single in which the Mars Volta wears its heart on its sleeve? That this most cerebral band is even showing its heart is fascinating all by itself. — Ronald Hart