Alter Klang (Ancient Loudness) refers to a famous picture of the same name by Paul Klee. The composer puts a wide range of sustained rhetorical resources and synaesthesiae into play, which emerge from the adaptation of the pictorial language to music. Although composed in only one movement for a large orchestra it is treated at several points as chamber music. It is dedicated to Josep Pons, who conducted the premiere at the Auditorio Nacional in Madrid in 2007.
Alter Klang, the orchestral impromptu by Benet Casablancas, whose rhetorical significance has aroused the interest of numerous European orchestras.