Understanding Sound Intensity: Simplified Guide to Hearing Range in Humans and Animals

Aren't you a physics enthusiast and hate math? No worries, for we've got your gluteus maximus! The last two posts (this and this) we wrote on this blog are quite technical. The first one explains how sound is measured in terms of intensity and pressure, without going too deep into the technical details. Sound intensity refers to the amount of energy a sound wave carries over a certain surface. This intensity decreases as you move away from the sound source because the energy disperses in all directions.

Decibels (dB SPL) are a way to represent how strong or weak a sound is compared to a reference level, like the softest sound the human ear can hear. The article explains how sound can be measured in terms of sound pressure, which is the variation in air pressure caused by the movement of sound waves.

When sound moves through a medium (like air or water), it encounters resistance, called acoustic impedance. This impedance affects the relationship between sound pressure and intensity. Simply put, the more resistance the sound encounters, the harder it is for it to propagate.

Moreover, sound gets absorbed by the medium in which it travels, especially at higher frequencies. This absorption reduces the intensity of the sound, which explains why high-pitched sounds or sounds in open spaces seem to fade faster.

The second post goes deeper into the concept of sound intensity and how it is measured, focusing on how it relates to sound pressure. By using decibels (dB SPL), we explain how the intensity of a sound can be quantified relative to the human hearing threshold. We also explore the differences in hearing ranges among various animal species, such as cats, lions, dogs, wolves, and bats, showing that each species has adapted its auditory sensitivity based on its environment and biological needs.

For example, cats have a hearing range from 48 Hz to 85 kHz, allowing them to hear much higher-pitched sounds compared to humans (who can hear between 20 Hz and 20 kHz). This ability helps them detect the sounds of small animals like rodents or insects. Lions, on the other hand, perceive lower frequencies, between 50 Hz and 10 kHz, which helps them detect prey movements or communications within their group.

Next, we cover dogs, which have a hearing range similar to cats but slightly lower, from 40 Hz to 60 kHz, and wolves, which can hear up to 40 kHz. This allows both species to detect high-pitched sounds, useful for hunting and social interactions. Finally, we examine bats, which have the most extended hearing range of all, from 1 kHz to 200 kHz, essential for their echolocation ability, allowing them to navigate and hunt in the dark.

In essence: we needed some basics of physics. We will probably talk more about advanced physics and math, but faithful to what Feynman said, if you can explain something in simple terms, like explaining it to a child or a beginner, then you truly understand it. I'm not Feynman, unfortunately, but I strongly believe that true understanding is shown through the ability to teach.

Until next time!