Listen to this week’s Key Studio Session and count the ways the guys in White Birds impressively play off one another. There’s vibey ensemble moments: Mike Cammarata’s minimal floor tom percussion provides the broken heartbeat to the tales of loss singer Jim Harvey spins thru a 60′s pop loom (“Floating Hands”). Chris Radwinski’s strolling bass line strikes a harmonic counterpoint to the scene in “Hondora.” But the breezy Bucks County psych band also works at the simplest level: “No Sun” and “Veins Lined With Rust” are carried by breathtaking harmonies between Harvey and his brother Farzad Houshiarnejad. It’s a far cry from the spastic carnival music these guys delivered as Drink Up Buttercup, but the band says you shouldn’t be fooled by the downtempo approach of its debut EP (or this session). It’s catalog runs broader, since it’s preparing to release a full length next year, and when White Birds opens for Jukebox the Ghost on Saturday, it promises energetic rock-out moments to break up the mellow mood. Get the full story when their session and interview plays back on The Key Studio Sessions Hour on XPN2 tomorrow night at 7. White Birds opens for The Spinto Band and Jukebox the Ghost Sat. Dec. 3 at Union Transfer. Tickets to the all-ages show are $14, more info at UTPhilly.com.