Characteristics
"Avant-garde metal" is interchangeable with "experimental metal"[1] and "avant-metal",[citation needed] and may also refer to a separate genre of "atmospheric metal" or "post-metal", which was named in reference to post-rock.[2] Avant-garde metal is related to progressive metal, but avant-garde metal often has more experimentation, while progressive metal usually has a tighter focus on traditional metal instrumentation and higher levels of technical complexity.[3] Avant-garde metal also uses unusual sounds, breaks conventions, and often includes new elements. The lyrics and visual presentation of the genre are eclectic as well.[3] According to Jeff Wagner in Mean Deviation, electronic percussion and drum machines see widespread use by avant-garde metal bands, along with female vocals and operatic elements, all of which he attributes to the influence of the band Celtic Frost.[4] The Canadian group Voivod also influenced future bands in the genre, pioneering technique such as robotic vocal effects, unusual time signatures, and fractured, dissonant, unorthodox guitar sounds.[4]