Once the last bone (the stapes) vibrates, it hammers up and down at a space called the oval window in the cochlea of the inner ear. The cochlea is filled with a fluid, and the vibrations of the stapes send pressure waves through the fluid. There is a membrane in the cochlea that is bent back and forth in different places based on the intensity of the sound, and the bending of the membrane causes small hair-like stereocillia to bend and send an electrical impulse to the brain to be interpreted as sound.
It pretty much makes you deaf. I wont get complicated, but pretty much, there are cells with hairs sticking out of them in an organ within your inner ear. When loud music plays, vibrations are sent from your ear drum, amplified through the malleus, incus and stapes and are passed onto the oval window. These vibrations are sent through a thick fluid called the endolymph and this moves those hair cells. The hairs (stereocillia) pick up vibrations depending on their length. If there is too much energy in the vibrations, the cells become useless and you lose hearing in that particular frequency... forever!