In a 2017 Classic Voice poll of the greatest works of art music since 2000, pieces by Haas received the most votes (49), and his composition in vain (2000) topped the list.
He grew up in Tschagguns, Vorarlberg, and studied composition with Gösta Neuwirth and Iván Erőd and piano with Doris Wolf at the University of Music and Performing Arts Graz, Austria.
Haas's style recalls that of György Ligeti in its use of micropolyphony, microintervals and the exploitation of the overtone series; he is often characterized as a leading exponent of spectral music.
His aesthetics is guided by the idea that music is able "to articulate a human being's emotions and states of the soul in such a way that other human beings can embrace these emotions and states of the soul as their own" ("Emotionen und seelische Zustände von Menschen so zu formulieren, daß sie auch von anderen Menschen als die ihren angenommen werden können").
[7] Haas has published musicological articles on the works of Luigi Nono, Ivan Wyschnegradsky, Alois Hába, Pierre Boulez, and Franz Schubert Archived 18 October 2018 at the Wayback Machine, among which: