Yes, an attack on a person/officer's auditory system is absolutely an assault. Your ears are biological organs connected directly to the brain. Deliberately exposing someone to damaging sound is no different in principle from striking their eyes with a laser, poisoning their lungs with gas, or striking the skin with force. Assault does not require visible injury. They're using sound as a weapon, and the intent matters. When sound is used intentionally to injure, intimidate, or impair a person’s hearing or neurological function, it meets every meaningful definition of assault. There is solid science behind this, and every person subjected to it is absolutely justified to respond to it in defense.