Michelle Bigenho wrote in Intimate Distance that Los Jairas, an ensemble founded in the mid-1960s... completely transformed the performance styles of Bolivian music.
Its practical size—four members—facilitated international touring, and the attention brought to it by foreigners finally made Bolivians take serious notice of what could be played on those instruments that were considered previously as just "cosas de indios" (indian things).
The floodgates of a new idiom had been opened, although in the case of Los Jairas it limited itself to the arranging of items in which Favre's and Cavour's brilliance could be displayed.
Vocal melodies would be entrusted solely to the kena, which played either solo or in thirds with a second kena... Favre's technique included a vibrato, a voluminous sound with a wide range of dynamic changes, a ubiquitous glissando between intervals a third or more apart, a distinctive phrasing, and a personal "signature," which was the raising of the last note of a phrase by a minimal pitch, thus creating a "tail," as it were.
The idea was to form a quartet of charango (Bolivian mandolin), guitar, quena and bombo (drum): instruments that had never been played together before, having had their own seasons in the mountain villages.
The quartet arranged the music to show off each of the instruments' solo and group possibilities.... they forged a new melodic and rhythmic style...[2]: 275