Extremely Rare 1973 Original Autographed On The Front Cover By Both Artists. VG+/VG+ "This Disc Pairs Two Compositions For Special Harps In 16th Tones Intervals, Known As Arpa Citera, Inspired By Mexican Microtonal Composer Julián Carrillo (1875-1965). Carrillo Divided The Octave Into Various Number Of Notes, From 16 To As Much As 96 Intervals For What Is Known As His Sonido 13 (“Sonido Trece”) System, Or The Thirteenth Tone. The Pair Of Arpa Citera Used On This Disc Were Presumably Built Around 1973 By Carrillo’s Last Students And Disciples David Espejo Aviles And Oscar Vargas Leal, Who Also Composed The Two Works Recorded Here. These Vertical Harps Can Play 400 Notes With Very Short Intervals. In Addition To The Strangeness Of The Tuning, The Musicians Use A Lot Of Ascending And Descending Glissandos, Decaying Tones And, Of Course, The Sounds Of The 2 Harps Also Create Harmonics And Unusual Intervals. This Eerie And Out-Of-This-World Music Will Be Familiar To People Already Accustomed To Ivan Wychnegradsky Or Alois Hába." Continuo Blog.