system
Given the following post, respond as if you're commenting on Reddit:
human
Why is high-frequency sound easier to block than low frequency sound?

I noticed that if you are standing far away from a sound source, that the high freq. notes tend to dissipate more rapidly than the lower freq. notes. Also, if you play music and step outside the room, only parts such as the bass guitar carry through the foundation. Why is this?

I remember reading somewhere that sound attenuation is quadratic with frequency, but I don't know why.
gpt
Low frequency means longer wavelength.

High frequency means shorter wavelength.

To block an oscillation, you need an obstacle (a screen, a damper, a block) that is larger than the wavelength, otherwise the wave will simply go around it by the phenomenon of diffraction. If the obstacle is much larger, diffraction gets smaller and smaller until it becomes unimportant.

Even if there is no diffraction, as in a cork in a pipe, it's still a good idea to make the cork bigger than the wavelength, otherwise it gets pushed and pulled by the wave and keeps bobbing back and forth with it. If the cork is larger than the wavelength, the wave gets reflected or absorbed more easily (the obstacle doesn't move as a single unit with the wave, but instead it starts to absorb it internally).

Sounds complicated but there's a simple way to visualize it: An ocean, the water is pretty calm, small waves. A cork floating on it. An aircraft carrier floating next to the cork. Ocean waves are much bigger than the cork, but are much smaller than the battleship. Which object deflects the waves, and which one lets them pass unscathed?

However, during a huge end-of-the-world hurricane, the waves are so large that become comparable with the carrier, which then cannot deflect them anymore.

Please note that the analogy is not perfect. Large ocean waves carry more energy compared to small ones, whereas long acoustic waves carry *less* energy than short ones. Yet both small ocean waves and small acoustic waves are deflected or stopped by larger obstacles. This shows that the main factor here is not the energy, but the wave length.

When you go outside the house, you keep hearing the bass because the wave is so big, the whole building is moving with it as a single unit, so the wave just goes through it like an arrow through paper. But the high frequencies are much shorter than, say, the wall thickness, so the wall doesn't move with the wave as a single unit - instead, the wall starts to compress and expand internally, under the force of the wave, and so the wave is dissipated inside the wall.

There's also reflection on the walls inside the room, and the idea is basically the same.

TLDR: Wave physics.