Bit depth and sampling rate (Beware this is Technical)

These days, lots of people want what they call an “analog” sound. But what does that mean? What does it mean to digitally record versus recording on tape?

Well, everyone knows that when you record something “analog,” you’re getting an exact reproduction of the sound wave, not a digital reproduction. But why is the digital reproduction not exact?

Because it is graphing the sound wave, so changing it into a language the computer can understand. The x axis of the graph is the sampling rate and the y axis is the bit depth. And really, it’s pretty damn close to exact these days.

When a computer takes in sound information, it is taking a measurement of where the sound wave is once every 44,100 seconds (or 88,200). The tiny instant between those measurements is where it does not have information, and has to guess what the wave is doing. In the same way a camera gives the illusion of motion if there are enough frames taken per second, a digital recording can give us the reproduction of a sound wave if enough measurements of that wave are taken per second.

So when you see 44,100 kHz or 88,200 kHz in your software, all it means is how many times per second the soundwave is being sampled. That’s why it’s a sampling rate.

Bit depth is something different. Sampling rate is the number of times the wave is measured, and bit depth is how accurate we can get the measurement. It’s the y axis of the graph.

Before I talk anymore about bit depth, I’m going to show off my new skill. I can count to ten!!!

1
10
11
100
101
110
111
1000
1001
1010

Well, in bits, anyway. Remember that bits are just 1s and 0s, which is how computers think. On (1) or off (0). A computer is just a gabillion on/off switches (more or less- my bf cringes a little at this metaphor).

1 is the same in binary language and in regular (decimal) numbers, but if I only have 1s and 0s available to me as counting numbers, then the next decimal number, 2, has to be represented as 10.

3 is 11

4 is 100

etc.

So the highest number that can be represented by three bits is 7, because 8 is already a four bit number.

The highest number that can be represented by 8 bits is 256. This means that with a 8 bit depth, you can only divide up your sound wave on a 256-notch y axis. This does NOT reproduce the sound wave very well, and when it plays back it has that wonderful atari sound.

With 16 bits, you have 65536 notches on your ruler. You know what the number 65536 looks like in bits?

1111111111111111

So you see that bit depth is just as important to good sound quality as sampling rate.

This is not the easiest thing to understand, but I do feel that it’s important to have a grasp of what digital recording actually is, compared to analog.

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