It wasn't entirely obvious that pairing the considerable talents of Bay Area singer-songwriters Thao Nguyen and Mirah Yom Tov Zeitlyn would lead to something special. But Thao and Mirah — the album they made after playing and writing together on tour — is 11 songs of heartfelt and ambitious modern folk. On "Eleven," producer Merrill Garbus of tUnE-yArDs strengthens the album's opening declaration with layers of background vocals and bouncy percussion, recreating the unassuming might that animates her music. "Little Cup," meanwhile, is whisper-intimate, with Mirah's precious falsetto leading a cloud of strings — until it takes off on a little jaunt. "Likeable Man" rides a spare, stuttering drum beat, a whimpering sax, and shining vocal harmonies. The ladies explore a huge sonic territory here; their complementary voices — Nguyen's is smokier; Mirah's is sweeter— trade off throughout, furthering the sense that neither wants the music to remain in one place for long.