system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: No matter how many videos i watch, I just can't wrap my head around the concept of Analog and Digital (in sound) and the difference between them. Please make it as simple as possible for a 16 year old with a slow brain like me.
gpt
All sound you actually hear is analog. You are hearing minute rapid pressure changes over time in the air and these happen continuously (as in there are no instantaneous jumps in the pressure, it rises and falls continuously and smoothly in time). It's a bit like drawing a wiggly line across a piece of paper.

The difference between analog or digital is how you store, process and amplify the audio - but to send it to your ears it needs to be made into analogue pressure changes in the air. 

Analog is something that operates on a continuum (wiggly line on paper), digital means it operates in discrete steps (you can think of it like a series of dots on the paper).

Take a light bulb and attach it to a switch. It can either be on or off - that's two discrete states so it's digital. Attach the light to a dimmer switch and it can have any brightness - it's operating in an analogue sense. Now you attach it to another switch which has 10 positions associated with 10 different brightness - it's still digital, but it's a better approximation of the analogue dimmer. Eventually you make a dial switch which has 1000 different positions - at this point its still digital under the hood, but effectively as far as a human can tell its an analogue device because the steps are so small.

Now you want to set the light to half brightness. On the analogue switch you do your best to turn the dial half way, but any minute error will be preserved. Let's say you're 1% off centre - your light will be 1% brighter/dimmer than you actually intended. On the digital one you turn it to position 500 - and every single time you can turn it there exactly time and time again. 

So back to audio - analogue sound is recorded as some continuous phenomenon like how magnetised a piece of tape is, or the shape of a groove in a record. This is fine, however each time you make a copy of the analogue original you can never make an exact copy. If you make a copy of a copy it gets worse. Inside an electronic device the signal needs to go from place to place and at each stage can degrade slightly - also its very difficult to avoid external electromagnetic background noise being added along the way. Inside a single device, like a record player it's not a huge issue - but when you want to transmit/share and move the audio to an audience around the world it becomes a problem.

Now comes digital, its operating in discrete steps, so you can store your audio as a set of instructions along the lines of "set to sound level 100, set to sound level 90, set to sound level 85...." and so on. Since these instructions are discrete it's easy to make perfect copies of them and share them with others.

These instructions happen thousands of times a second. CD digital audio files have 44000 instructions per second and each instruction can be set to any of 65536 different levels - so it's actually quite a lot of data. There are tricks to compress this to less data while minimising audible differences but that's another topic. 

To actually produce the sound from a digital source, you need something called an analogue to digital converter. There are a few ways to do this, but essentially you take all your discrete points in time and you join/smooth them together like drawing a smooth line through a set of points on a graph - this smoothed continuous signal can then be fed into a speaker (you can also feed certain digital signals into the speaker directly and the speaker does the smoothing for you since it can't move instantly from one position to another). To save digital audio in the first place, you use an Analogue to Digital converter which takes a reading from the microphone tens of thousands of times a second.