Brother and sister Theo (a onetime House List writer) and Sasha Spielberg began making music as Wardell several years ago in Los Angeles. Influenced by the disparate likes of Led Zeppelin, Fiona Apple, the Strokes and Joni Mitchell, the bicoastal (he in New York City, she in L.A.) indie-folk duo put out their aptly named debut EP, Brother/Sister (stream it below), in 2013, with Sasha on vocals and Theo handling the instrumentation. Afterward, they really began to work on their sound while performing live, including a plum gig opening for Vampire Weekend and Haim at last year’s SXSW. Today, Wardell (above, doing “Funny Thing” and “Love/Idleness”) see the release of their debut full-length, the charmingly easygoing Love/Idleness (stream it below). And they celebrate its release tonight at Mercury Lounge. Bushwick dream-pop four-piece Arc Waves open the show.