Eli5 Why does sound ‘sound’ different e.g. in a room through a microphone compared to my ears?
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I have built a binaural audio recording set where i tested it for the first time in my bedroom and I wasn’t prepared for the sound to be so “boxy”. But the pair (two mono microphones) are really good quality, why does it sound different?
Got a sample to share?
Different spaces definitely sound different.
Also positions of everything matter. Sound interacts with everything.
Microphones don’t exactly reproduce the sounds of an environment, they are better at registering sound of specific frequencies than others [example](https://images.app.goo.gl/1W64MScKqJ535W3u7) of an sm58’s frequency response. If you look at that you’ll notice that sounds < 150 hz are picked up at a lower db than sounds around 1000 hz. The boxyness and other audio artifacts are introduced because the mic is reproducing what it heard, not whatever the sound recorded actually was.
One big reason is due to psycho-acoustic effects. Your brain interprets signals from your ears and subconsciously “compresses” parts of the sound that the brain recognizes as unimportant, like high frequency hiss or low rumble.
It’s not just the microphone that changes the sound, you also have to consider the recording medium, the recording method, and the play back method.
Each of the components involved in the recording and playback have difference sensitivities to both different frequencies and sound pressure levels (loudness). They also add noise and distortions into the sound.
Different components will over or under-emphasize certain frequencies because everything has natural frequencies (think about singing in the shower where certain notes have extra resonance).
Some echoes and reverberations in the room may be of a low enough volume that the microphone or speaker is unable to replicate it. Recording playback systems can have greatly reduced dynamic range than real life.
Another difference is that a microphone is sampling the sound from a single point. You have two microphones on either side of your head providing you information of where sounds originate from. Electronic playback tries to use signal processing tricks to recreate this, but they cannot exactly replicate your particular ears.
In short there are a bunch of little things that you may not notice, but in sum total your brain says something is just a bit off. With very expensive equipment and setup we could probably make it very difficult to tell the difference, but it is not critical for most people.
Ears are really great at hearing sound and sending it straight to the brain. The human body works really well!
When we record music we use use man-made things to listen to sound. These can be amazing but nothing is really as good as the human body on its own!
The sound changes because of using man-made things like microphones and mixing desks and computers to record the sound.
When recording microphones will pick up ‘room noise’. This means how things sound in that room. The sound changes if you are in different kinds of places. Think of how big places where most things are hard and shiny, the sound bounces around and even echoes! But in a place where lots of things are soft or it’s small, the sound is more muffled.
This is because sound moves through the air in waves, and it changes its direction if it hits something – like ocean waves. Some things reflect the wave back. Some things don’t – they absorb the sound. So most recording studios have lots of things that absorb the sound – anything soft, carpets, foam, soundproof booths etc. You can do a craft activity and make your own sound booth! Eggshell foam, egg cartons stuck to cardboard/in a box to make a vocal booth, or make a mattress or cushion fort with any other soft things you have – blankets, linen etc 🙂
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