Considered one of the godfathers of Americana, Dave Alvin is having one of the most unexpected rebirths in recent memory. His new effort, Ashgrove, is being hailed as some kind of modern blues classic. It isn't. Remotely clichéd (as was his work with the legendary Blasters), it is, however, dynamic. With the proper inebriation, the lights low and the smoke quotient high, this could be one of those nights when blues and country blissfully intermingle, when the passion is as important as the playing, when the singing is off-key and a ragged-but-right performance (almost) justifies the hangover.