People can protect themselves from very loud sounds either 1) by being somewhere other than where the sound is, or 2) by putting a sound barrier between themselves and the source of the sound.
Sound barriers can be
Personal protective equipment is by far the least effective protection from loud sonds, but somethings must be used as a last resort when everything else has been placed and is not effective enough, or when the other methods cannot be applied for practical reasons.
Ear defenders could be used to protect your ears!
An earplug is a device that is meant to be inserted in the ear canal to protect the wearer's hearing from loud noises.
you can put head phones in or ear muffs or you could just not the loud sound in the first place
By walling their cities and establishing citadels for refuge. By fighting in front of their cities. By having navies. By forming defensive leagues with other cities. By training for warfare in their spare time. By hiring mercenaries.
anything as loud or louder than a little girl screaming
Yes, some continuous loud sounds are related to hypertension (high blood pressure). In addition, sounds outside the audible range can make some people nauseous, etc., even if they are not all that loud. Loud sounds if sudden, sharp and loud enough, may damage your ear drums. An loud sounds experienced over a long enough period of time can damage your hearing.
Narwhals protect themselves by using their tusks as weapons. there horn
Loud speakers can produce ultrasonic waves. But since the normal purpose of loud speakers is to produce sounds for people to hear, there is seldom a reason to produce sounds that people can't hear (other than to annoy certain animals).
Loud sounds instruments
Regardless of psychological condition, loud sounds can cause brain damage, due to vibrations in the skull. In people with "sound phobia", this effect can be increased by the normal stress reactions to loud sounds, however there is a slight lack of research supporting this.
Yes, most horses react to loud sounds unless trained not to.
Drums, trumpet, violin, and many more, make loud sounds.