so when i first listen to metal i think i was 13-14 years old i always think why i must listen outside of metal music because on metal we can heard anything musical influence's start from blues,classical,jazz,punk,hardcore,etc. but 7-8 years later i am realized i need back roots of metal music. cause you know if there's not classical or blues or proto rock music. there will not be metal sub-genre even will not exists. so i decided to learn all kind of music which related with Metal music improvement yeah not only blues,classical also some ambient music,jazz (which later inspired Technical death metal, avant-garde/experimental metal band) ,hardcore,punk,folk music and even some pop song i've listen to and i try to learn some electronic music too