not sure if this is in your field but can I ask how speakers work? like how does the sound of a human come from an electronic machine by only wavelengths? if this is more of a physics question just skip me I apologize

note: absolutely anybody should be able to read this post regardless of competence level

let’s quickly go over how sound works:

your diaphragm muscle, sitting above your pelvis, pulls your ribcage inwards constricting your air-filled lungs. this creates pressure in your lungs and forces air to travel through your windpipe, across your vocal cords, and out your mouth. your vocal cords wiggle and flex to mix up the air coming out of your mouth such that it doesn’t come out as one continuous “blast”, but as sequential “layers” of pressure-varying gas


sound is pressure waves:

in the image above, imagine the little black dots are air molecules. the tight clusters of them represent an area of high concentration, or high pressure (your vocal cords relaxed, for a few milliseconds, and let your diaphragm push out air at “full throttle”). the areas with less concentration are the opposite of this, obviously, where your vocal cords constricted and let out less air molecules resulting in a region of lesser pressure

again, these sequential & rapidly cascading “layers” of air pressure is what creates the illusion of sound. they crash across your eardrums, like waves on a beach, pulling it back and forth at different frequencies which is to say that however closely-packed those alternating layers of high/low pressure regions obviously has an impact on how quickly your eardrums are pulled back and forth. this is how pitch varies, or why the sound of a humming motor sounds different than a baby screeching. the difference between how tightly-clustered the air molecules in the high-pressure regions and how loosely-clustered the air molecules are in the low-pressure regions are is what creates the illusion of volume, or why a whisper sounds different than a shout


a speaker can accomplish this varying-of-pressure-waves-to-create-sound idea in a much more articulable way than our vocal cords do. you simply have a speaker cone:

move back and forth very quickly to push/suck air backwards and forwards to create pressure waves. how do they do this? 

above is an image of conductive wire wrapped around a cylindrical core made of metal. if you connected a battery to this contraption such that electricity flowed from the left endpoint of the wire to the right, the metallic core would be pushed in the right direction. if you switched the battery connections such that electricity flowed the other way, the core would be pushed out in the left direction. this happens because of complicated physics that aren’t worth getting into in this post. in a speaker, the metallic core is attached to the speaker cone such that the speaker cone moves with the core


if you quickly alternated the voltage on the wire, the metallic core would vibrate back and forth in accordance to the electricity flowing forwards/backwards in the wire. let me illustrate:

if you looked at the electrical waveform coming out of an AUX jack on your phone, it would match the waveform of the whatever audio it is playing. the electrical wave moves through the wire coil causing the metallic core to move forward/back causing the speaker cone to move forward/back, creating sound in the way we discussed before

hope this explains things