Avant-garde metal, also known as avant-metal or experimental metal, is a subgenre of heavy metal music loosely defined by use of experimentation and characterized by the use of innovative, avant-garde elements, large-scale experimentation, and the use of non-standard and unconventional sounds, instruments, song structures, playing styles, and vocal techniques. It evolved out of progressive rock and extreme metal, particularly death metal and black metal[citation needed]. Some local scenes include Los Angeles, the San Francisco Bay Area, Boston, and Seattle in the United States, Oslo in Norway, and Tokyo in Japan