So imagine you have never heard of music before. Avant-garde metal is like playing with different sounds and noises to make a type of music that sounds really unique and different from what you are used to hearing. It is like mixing different colors of paint to create a new color that nobody has ever seen before.
In this type of music, the musicians use a lot of weird instruments, like percussion instruments or electronic devices, to create new and strange sounds. They also play with different rhythms and melodies that sound very different from what you might hear in pop or rock music.
Sometimes, they might even use their voices in weird ways or use different languages to add to the uniqueness of their music. This kind of music is not really meant to be mainstream, but more for people who are interested in hearing something really out of the ordinary.
So, in short, avant-garde metal is like cooking up a completely new kind of recipe in the kitchen, but instead of using food, musicians use strange and unique sounds to make music that is different from anything you’ve ever heard before.