Can frequencies too low or high for us to perceive damage our hearing?



Generally speaking, frequencies below 20 hz and above 20 khz are not audible, but can high enough amplitude of these frequencies damage our hearing?

In: Biology

I saw a TV programme where they did a test of the “brown note” and subjected someone to a 4 Hz frequency at high amplitude. Basically massive speakers with a lot of energy driving them. The sound engineer in charge was insistent that everyone wear these big hefty ear muffs to protect their ears because, even though the sound is in audible, it would still cause damage at that amplitude.

In short, a 4 Hz “sound” is moving pressure waves, and high amplitude means a greater difference in pressure between the peaks and troughs of the wave. Your ears are sensitive to changes in pressure, so these “loud” inaudible frequencies would still cause inner ear pain and damage.

Short answer:

ultra low frequencies yes, ultra high frequencies no.

Very high amplitude low frequency sound is essentially the shock wave from an explosion. A single pulse of a massive concussion wave can indeed rupture your ear drum and cause significant damage.

Very high amplitude HIGH frequency sound, however, can’t resonate with your eardrum and generate the vibrations necessary for you to experience any sound. Your inner ear fills with fluid to dampen the excessive movements of the ear drum, and too much of this without time to recoup actually softens the bones of the inner ear. This dampening fluid is why when you leave a rock concert everything sounds muffled. Since physical hearing damage is caused by your body reacting to your ear drum vibrating too much, if the sound waves don’t cause your eardrum to vibrate then nothing happens.