These quartets are transcriptions of performances by what was then known as the Bulgarian State & Radio Female Vocal Choir in their recordings Le Mystère des Voix Bulgares. In the mid 1980s, the first of these recordings introduced modern interpretations of Bulgarian folk music sources in new compositions and arrangements for 24 female voices. The resulting sound is homogeneous, clear timbres without the vibrato familiarly utilized in Western art music. Combined use of asymmetric meters, nonfunctional harmonies and dissonances as integral parts of the harmonic structure gives this music its unique character. The range and relatively unadorned, clear tonal quality of the music lends itself particularly well to that of the horn ensemble. Other than some unique vocal techniques and instrumental accompaniments, these transcriptions remain faithful to the originals, both stylistically and harmonically.
The five pieces retain their original Bulgarian titles and translate, or are subtitled, loosely as: