The beginning of the digital age
binary code
Although digital audio is the standard of music these days …
It has not always been this way.
Music originally existed only in the form of sound waves.
Then, with the development of technology, ways were discovered to convert it to other formats, such as:
Musical notation
electrical signals in cables
radio waves in the atmosphere
request on vinyl record
But more recently, in the age of computers, digital audio has become the main recording format, making it easy to copy and transfer songs.
The device that made this possible is called … digital converter.
Also, on how it works …
2. Digital converters
In recording studios, digital converters exist in 2 versions:
as a standalone device in top studios or …
as part of an audio interface in home studios.
To make binary code out of sound, they take tens of thousands of images (samples) per second to build a rough image of an analog wave.
This image is not entirely accurate, because in the moments between samples, the converter has to guess what is happening.
digital wave
As seen in the graphic above:
the red line shows an analog signal and …
black line shows conversion …
The results are not ideal, but sufficient to produce excellent sound quality.
And the difference depends mainly on …
3. Sampling rate
Take a look at this image:
sampling rate circuit
As can be seen …
By capturing more images per second, higher sampling rates:
Collect more real information,
Use less guesswork,
Creates a cleaner display from an analog signal
And in the end, you get the best sound quality.
Now let’s talk about specific numbers:
Standard sample rates in professional audio:
44.1 kHz (CD)
48 kHz
88.2 kHz
96 kHz
192 kHz
44.1 kHz is the minimum sample rate due to a mathematical principle known as …
Kotelnikov’s theorem (Nyquist-Shannon)
To accurately record digital audio, converters must capture the full spectrum of human hearing between 20 Hz and 20 kHz.
According to Kotelnikov’s theorem …
Capturing a specific frequency requires at least 2 samples per cycle … to measure both the high and low points of a wave.
This means that a sample rate of 40 kHz or more is required to record frequencies up to 20 kHz. Therefore, the sampling frequency of CDs is slightly higher, 44.1 kHz.
Kotelnikov’s theorem
Cons of a high sample rate
Although the higher the sample rate, the higher the sound quality … but this just doesn’t happen.
The cons are:
Requires a lot of computing power
Less clues
Large audio files
So this is a constant search for a compromise. Professional studios find it easier to deal with high sample rates because they have the best equipment.
However, for most home studios, the standard 48 kHz sample rate is appropriate.
