How does the digitization of sound work

Analog to digital - this is how digitization works

It's crazy how technical our world is today. Internet, information and entire music collections are on the smartphone in their trouser pockets and only a few people can still look through the technology that is running in the background. We cannot explain the whole world here either, but at least how the digitization of analog audio material into the computer works, we try to put it in simple words.

The analog audio signal

When scanning the sound carrier, whether cassette or record, a continuously oscillating voltage is generated and conducted to the loudspeakers. This oscillation can take any value between an upper and a lower limit.
The longer the transmission path of an analog audio signal, the more susceptible it is to interference. The actual signal is then masked by noise. This problem also occurs when copying from one sound carrier to another several times.

The digital audio signal

Digital signals, on the other hand, work differently. This is where the "Tone curve" through a grid, each column of this grid stands for a unit of time. The smaller the grid, the more precise the digital signal, but it also requires more memory.
The size of the grid is also called sampling rate or Sampling frequency designated. For one Audio CD this is included 44.1 kilohertz, the grid offers 44100 columns per second for the audio signal.

Our sound curve now runs through a grid that is endless in length (well, almost). But what determines the height of the grid? This amount is determined by the Word length. To stay with the example of the CD, this is 16 bits. 16 bits offer 65536 different gradations (16 to the power of 2). Our audio signal can therefore spread over 65536 lines in our table.

The digital audio grid is very fine on a CD, this results in the high sound quality. Every point on our sound curve has, so to speak, a fixed address, which means that interfering noises such as hiss hardly have a chance to occur.
When recording in the recording studio, much larger values ​​are used, but as we have already learned, the memory requirement increases accordingly.

The scanning process for digitizing

So we now know the analog and the digital audio signal. When a record or cassette is recorded in the computer, the analog audio signal is scanned with the aid of the digital grid. Just try it out to record your sound carriers with less than 44.1 Khz and with only 8 bits. You will hear with your own ears how an enlargement of the grid and, with the accompanying reduction in resolution, the sound quality becomes significantly worse.