Long before 'world music' was a widely used term, ethnomusicologist and performer Mickey Hart became enamored with the culture of rhythms. After hooking back up with the Grateful Dead in the mid-'70s, Hart began incorporating advanced time-signatures into the "Drums" portion of the "Rhythm Devils" duets with Bill Kreutzmann (drums). As described in the liner notes, this is something of a soundtrack album for a planet called Däfos (1985). Hart (tar/beam/stick/tubular bells/percussion/berimbaus/saron/vocals) is accompanied by Steve Douglas (woodwinds), Shabda Khan (tar), Jody Diamond (saron), Bobby Vega (bass), Flora Purim (vocals), Airto Moreira (percussion) and the Brazilian group Batucaje among others for a collection of ambient soundscapes adorned by an array of indigenous hand and mallet-struck percussion. Although dominated by instruments, Flora Purim's vocals during "Reunion I" through "Reunion III" are equally as expressive as Vega's propulsive electric bass interjections, backed by Hart and Moreira's perpetual pursuit. "Saudação Popular" is one of the cuts to feature Batucaje, who join Hart on berimbau. The instrument's wah-wah effect is produced by the bow-like object that is struck, while the frequency is controlled by the amount of pressure the player places when moving it against the body. The mid-tempo tune incrementally increases in speed to match the intensity of the participants fervor. "Psychopomp" is Hart providing ambience on the amplified piano-string Beam -- that was often the highlight of the Grateful Dead's "Space" jams. The hollow, almost metallic "Subterranean Caves of Kronos" is once again just Hart on a series of subdued melodic tubular bell progressions. Conversely cacophonous is the multi-drum Beast, a 25-foot round aluminum frame able to support a capacious assemblage of drums. Its use became another zenith of Grateful Dead shows and Hart gives it a workout on the hell-bound "Gates of Däfos." According to the brief text supplied for each song title, the lengthy "Passage" depicts the journey once inside the Gates of Däfos, which develops from the atmosphere of a pastoral setting to the urban sounds of sambas and celebrations. Upon its release, Däfos (1985) garnered substantial notice from audiophiles, including a write-up in Absolute Sound that is reprinted in the Rykodisc CD edition.