The sample rate is how many times per second you capture the signal. The bit depth is the number of bits of information in each sample. The bit rate is the sample rate multiplied by the bit depth.
In order to accurately reproduce a frequency of sound you need twice the sampling rate. So if you want to reproduce a frequency of 20,000 hz you need to sample it at 40,000 hz (or 44.1 for CD). Higher sampling rates result in reproducing higher frequency sound. Since most people lose the ability to hear sounds above 18,000 hz by the time they are adults, the difference in sound between 44.1 khz and 96 khz and 192 khz is negligible but some people believe that higher harmonic frequencies can be perceived in other ways.
The number of bits that you use for each sample will affect how many levels of loudness each sample can reproduce. If you had a sine wave which looks like a squiggly line, or the peaks and valleys of a mountain, the sample size is how thinly you can slice the mountain vertically. The more slices, and the thinner the slices, the closer the curve of the original signal is preserved. If you have a smaller sample size, you tend to cut the signal thickly and end up with something more like stairs vs the smooth natural curves of peaks in an analog waveform. These are the soft and loud sounds and the difference between them is the dynamic range.
a 16 bit sample can reproduce 65,356 levels of sound. So if one sound is slightly louder or softer, the difference is mostly left intact. Low sample sizes like 8 bit can only reproduce 256 levels of sound, which sounds artificial with sounds jumping between two levels because there is no in between.
24 bit samples are capable of 16 million levels which is generally more than a persons ear is capable of perceiving. But there are other uses for it. When you have a very quiet piece of music, if you are not maximizing the loudness of the audio sample, then a lot of that sample goes to waste. Like if you had a quiet track that never peaked above level 30,000 then the other 35,000 levels of detail go unused and the effect is like if you had a lower sample size. But 24 bit samples are so large that even if you only peak at half the sound level, that's still 8,000,000 levels, far more than the best 16 bit ones.
TLDR, higher sampling rates give you higher frequencies without distortion, and larger sampling sizes give you smoother reproduction of loud and soft sounds, closer to the nice round wave forms of an analog signal, vs the stair stepped squarish wave forms of a poorly encoded digital one.
Source: https://www.reddit.com/
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