Question: Ehnahre is a ensemble of a music subgenre that has developed since the early what?
Sentence (from "Ehnahre"): Their music incorporates elements of Contemporary classical music, Aleatoric music, Doom metal, and Death metal, and utilizes extended techniques, aleatoric rhythms, aspects of Serialism, and elements from free improvisation, contemporary chamber music, and extreme metal styles.
Relevant evidence: No