Eli5 How does music from a live band for example travel through wires and digital formats yet sound exactly the same when coming out of my headphones?
In: Technology
Alright, buckle down for this one.
So. Sounds is the movement of atoms. Specifically the pressure changes the movement of atoms and molecules cause by moving.
With that in mind, our ears picks up on those pressure changes and our brains puts them into information we call sound.
Microphones do the same sort of thing. There’s a small sheet of very thin metal that vibrates when sound hits it, which is then converted into depending on what type of microphone either fluctuation in voltage if you have an older microphone, or directly into ones and zeros if you have a digital microphone.
That fluctuation in voltage or the one and zeros can be fed into a speaker, speakers have the same basis of the thin sheet of metal that vibrates the right way to replicate what the sounds wave looks and sounds like.
Old type cables work the same way two tin cans on a string do. But with electrical signal rather than direct vibrations of the string.
I know i missed some more technical stuff here, ask away if you have any questions.
All that sound is is just a very complicated pressure wave: the air shaking back and forth in a set, complicated pattern.
If you have some method (a microphone) that can record those pressure waves, and then later use the recorded information to tell a speaker how to shake the air around it the resulting pressure wave will be interpreted by our ears and brains as the same sound.
Sound is just vibration. If you pluck a guitar string, that string will vibrate the body of the guitar, which vibrates the air, which vibrates your ear drum, which then is translated by your brain into sound.
To record sound, a microphone is substituted for your ear drum. The sound vibrates a membrane in the mic. The membrane is attached to a magnet suspended in a coil of wire (I’ll just use one mike type of this example). When the magnet movies, it creates current – how much current is based on how membrane moves. This process can also be reversed – you can use current to move a magnet at the other end, which can move a membrane and make vibrations in the air. This is how a speaker works.
Recording just takes snapshots of the current in the wire periodically and records the values of the current as computer data. This is known as the sample rate – how often it takes a snapshot of the current. Again, this process can be reversed – you can use those snapshots to produce current in the wire, which is used to drive a speaker. That is how playback works.
So, it is all about taking a vibration and converting it to current, then converting that current to data (and reversing the process).
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