After fizzling in the wake of the acid rock movement of the ’70s and spending the last 30 years in obscurity, Brazil’s wildest psychedelic rock band, Os Mutantes, reunited for a historic concert at the Barbican’s Tropicalia Festival in London in 2006 — much to the delight of their small but fanatical following. Throughout the performance, powerful bass lines, intricate polyrhythms and swirling vocal harmonies drag the listener from one end of the psyche-tropicalia spectrum to the other. The two discs are dense with melodies, quick time-signature changes and heavy doses of effects. At times, American pop influences ranging from Jimi Hendrix to Brian Wilson are apparent, and later in the album the sound is more rooted in traditional bossa nova, but always with a twist. Musically, it’s a complex mix, and lyrically, it jumps heavy-handedly between English, Portuguese and French.

Mutantes Live captures the manic messiness of the band’s music with a clarity that cannot be found on their original recordings from the late ’60s and ’70s. This is due in no small part to the sophistication of the modern technology now at their disposal and the massive roster of talented musicians needed to replicate the sound originally conceived by the three founding members. Despite the complexity, though, the album’s finest moments occur when the musicians are able to get into a groove — which, unfortunately, never lasts more than a few seconds at a time.