Recently I bought a SHZ-84 helmet, only to find that its headphones didn't work... so I changed them.
Step 1: Removing ear muffs
6)music player (my phone)
First you have to cut off the yellowish ear muff things. Do this very carefully by simply cutting the yellow muffs from the fur and rubber. Now you should see the speakers inside their rubber casing, just pop them out. Unscrew the red and green wire from the speaker-tablets and pull the wires from the helmet.