eli5 – How does Dolby atmos work and make your brain think sound is coming from an area with no speakers?
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Dolby Atmos speakers bounce the sound off of the ceiling to make it appear as if the sound is coming from above.
In general, how stereo tech like atmos get 3D soundscape out of just two speakers? They play tricks with how sound is received by your ears.
The majority of sound that your ears pick up comes via soundwaves in air, hitting the eardrum and the pressure vibrations are picked up by the cilia in your inner ear. To make stereo sound, its easy – simply delay the audio signals travelling to one side of your head vs. the other – your brain is smart enough to figure out “oh, I heard that sound first on the left, then the right. Sound must be coming from my left.”
The little hairs inside your ear can also pick up sound vibrations that travel _through_ your body as well. By taking advantage of how we know sound is attenuated or muffled by the human body we can fake the sounds that we shove into the ear to mimic that. We’re sending those through your ear, but to the hairs inside your ear and your brain that is interpreting them, the end result is the same as though the sounds had travelled through your body. Thus we can mimic 3d soundscapes.
Atmos does the same type of thing, just adds a vertical dimension.
To be fair… the setups without speakers (soundbar bouncing off ceiling vs actual speakers in the ceiling) are kinda gimmicky. It definitely works, it just isn’t a game changer.
But yes, long story short, it bounces off the ceiling. My soundbar setup has speakers facing upward at roughly a 66 degree angle. Additionally, the equalization is set up for my room. The system played various sounds while I walk around with my phone so it could understand my room’s acoustics and equalize itself.
Propper Dolby Atmos like my setup comes from 5 speakers around the room at ear height and 4 speakers from a raised location (one in each corner) therefore the sound actually comes from above.
The Dolby Atmos that you see from 2 speakers uses an algorithm to make sounds, sound like they are higher and lower.
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