The Gipsy Kings began as a family band of singer-guitarists who played a traditional Gypsy take on flamenco. Because they all played the same instrument and all sang tenor and baritone, their harmonies and rhythms were very tightly woven, but their range was very narrow. They solved that limitation in 1987 by coupling their guitars and voices to the Europop sounds of synthesizer, bass and drums, winning sudden, widespread success in the process.

For their new album, "Roots," the Gipsy Kings wanted to get back to their original, acoustic sound without getting stuck in that same narrow range. They invited American producer Craig Street (Cassandra Wilson, Norah Jones) to a French farmhouse to help revamp their approach. Street got rid of the synths, electric bass and trap drums, but he brought along acoustic bassist Greg Cohen (Tom Waits, Dave Douglas) and hand drummer Cyro Baptista (Paul Simon, John Zorn) to bolster the bottom while preserving the project's all-acoustic nature. Street even added Garth Hudson's accordion to two tracks.

The results revitalize the Gipsy Kings sound, which had grown a bit formulaic in recent years. Because there is less clutter in the arrangements, the single-note guitar virtuosity of Tonino Baliardo comes through more forcefully than ever, especially on Django Reinhardt's "Nuages" and the original instrumental "Bolerias." Likewise the vibrant tenor of Nicolas Reyes cuts through on the up-tempo songs such as "Aven Aven," while Canut Reyes and Patchai Reyes handle the slower, sadder vocals. Through it all, Cohen's prodding, probing bass lines stretch the harmonies and keep the rhythms unpredictable.

-- Geoffrey Himes

Appearing Tuesday and Wednesday at Wolf Trap. * To hear a free Sound Bite from the Gipsy Kings, call Post-Haste at 301-313-2200 and press 8103. (Prince William residents, call 703-690-4110.)