POP MUSIC REVIEW : Optimistic Air at X Benefit Show : The Roxy event for a Santa Monica homeless aid center was headlined by the band, which plays in O.C. Thursday.

Maybe it’s the impending changes in Washington, or maybe that the outgoing President is closing his Administration with a mission of mercy, but there was an air of optimism over the gathering of Los Angeles musicians in aid of the St. Joseph Center, a Santa Monica homeless services facility, at the Roxy on Tuesday. It was an uneasy, cautious optimism, perhaps, but it was a marked difference from the frustration that has characterized such events in the past.

Even “Arms for Hostages,” a new song offered by headliner X, is a tentatively hopeful relationship metaphor rather than the Iran-Contra indictment one might have expected from the title, as well as from the group’s track record of outspoken social activism.

But then, X has always been at its best covering personal matters in song and leaving its politics to its actions, such as playing at this benefit.

As such, the quartet’s acoustic set revealed a band looking forward, heads up, with new songs carrying emotional power and depth and such old favorites as “White Girl” and “Motel Room in My Bed” turned, for this occasion, into ‘90s beatnik shuffles.

Michael Penn and Peter Himmelman offered sometimes mesmerizing slices of melodic-romantic and spiritual quests, respectively. Sacramento-based Mark Curry provided the evening’s intensity with a decidedly non-acoustic band fleshing out his restless, complex yet focused rants. His trailer-park frustrations followed and contrasted the street salvation of the night’s surprise highlight, a brief set by Ted Hawkins, a once-homeless singer whose gracious and glorious folk hymns encapsulated the show’s aura of hope.

X will play on New Year’s Eve at the Rhythm Cafe, 3503 S. Harbor Blvd., Santa Ana. Show times: 7:30 and 10:45. $26 to $27.50. (714) 556-2233.