About five years ago, the duo of Tingstad & Rumbel dropped the ersatz jazz rhythm section they'd been using and went back to what they did best, evocative and pastoral duets for guitar and oboe. It brought a new freshness to their compositions and playing. With Acoustic Garden, the rhythm section returns, and it conspires again to make their music stiff and metronomic. They bring in several pianists, including David Lanz, to flesh out the harmonic landscape. But they only help on a few tracks, notably Tom Kellock enlivening the Celtic-tinged "Shamrock." Some lovely songs, including Rumbel's arrangement of a Chinese lullaby, "Clear Moon, Quiet Winds," and their co-composed "Prairie Schooner," emerge, but they push through a haze of kudzu, pretty on the surface, but choking the life out of every place it invades. --John Diliberto