I am sitting in my apartment with my windows open and a car drove by and as it did, the music got distorted the further away to got. I’ve noticed this too while walking to class and someone is blasting music in their car.
In: Physics
Basically the frequency at which the sound waves are reaching your ears is increasing or decreasing. As a vehicle moves towards you, the speed of sound stays the same, yet the vehicle is getting closer to you so the sound has less distance to travel. As it passes you and goes further away, so too the sound waves have further to travel to get back to you as the vehicle gets further. Think of it like walking into an ocean from the beach. If you were to walk straight into the waves, the frequency they hit you with would increase the faster you walked. When you turn around to go back to the beach, the waves would take longer to hit you since you are walking away from them.
It’s called the Doppler Effect.
https://en.m.wikipedia.org/wiki/Doppler_effect
This is called the Doppler effect. The sound waves are closer together as the car drives towards you because the speakers are moving as they create the ripples in the air. This makes the pitch of the sound higher. As the car drives away, the waves are further apart than they would be if the car were not moving, so the pitch gets progressively lower.
Interestingly, the same thing happens to light waves when we observe really distant and fast moving objects, but instead of sounding higher or lower, the light looks more blue or red.
Another thing that changes is that different notes – frequencies – are absorbed differently. In particular, the high tones are mostly absorbed by the car’s structure, and the air, but the low tones – the base, the beat – travels further through through the air and even through the ground.
People often talk about ‘Doof Doof’ music, because outside the car, from a distance, all you hear is the beat – all the higher tones in the music are lost.
Latest Answers