The most grounding music may just be the type of music you like the least. The other factor in getting grounded is breathing. When you are scared or nervous your breathing changes. It can get very shallow and rapid. This will cause you to hyperventilate.
Hyperventilation triggers certain responses in the body that make grounding pretty difficult.
This is due to changes in the brain chemistry during shallow breathing. Hyperventilation also restricts the flow of blood to your hands and feet. This physical response will quickly contribute to not being grounded. For this reason, always pair any grounding technique with deep breaths that move your stomach. The combination of grounding techniques and 'stomach' breathing is very powerful and can work very quickly.