In this video, we learn how to use your diaphragm to scream sing. This is what you would use if you were doing death metal vocals to scream in a song. You will need to use the voice from the back of your throat, but make sure you aren't using the wrong portion of your voice to breathe too hard, or you will lose your voice quickly. You want to deep breathe and use your diaphragm to pull the deep sound out of your throat. This will take practice to get used to, but it will help you sound deeper and won't cause you to lose your voice.