Mp3, the star format, the reasons

Another interesting property of hearing is that the lower the volume level, the lower its resolution, the lower the number of sounds perceived. When the volume is lowered the high frequencies are better perceived, when the volume is increased the low frequencies are perceived. And they do not complement each other, but rather replace each other.

A person does not perceive some sounds, focusing on others. Pay attention: an instrument, or a voice, is usually audible clearly and consciously. Everything else becomes a background or a single tune. And no matter what we focus on in composition, we cannot increase the number of basic sounds perceived.

How to create the mp3

All these data obtained from experimental studies are gathered and presented in the form of an ideal model of human hearing. The MP3 standard focuses on this.

Everything that a person does not hear unambiguously is immediately cut off. Post-processing degrades the sound according to the understanding of this model.

Thanks to the great work done, modern psychoacoustic models accurately evaluate human hearing and do not stand still.

In fact, despite the assurances of music lovers, musicians and audiophiles, to the inexperienced middle ear, the highest quality MP3 has almost extreme parameters.

There are exceptions, they cannot cease to exist. But they are not always easily noticed by blind listening. And they are no longer derived from the mechanisms of hearing, but from the algorithms for processing sound information in the brain.

And here only personal factors play a role. All of this explains why we love different headphone models and why the numerical characteristics of the audio cannot unequivocally determine the sound quality.

MP3 fits everything: analog quality

Audiophiles’ insistence on picky FLACs is worth going through another serious sift. Most analog recordings do not contain enough information for lossless formats.

All CDs are recorded at 44.1 kHz sample rate and 16-bit quantization. Where does 192 kHz and 24/32 bit come from, which is used when encoding in FLAC? They are not, this is a doll!

You will object that these parameters are higher for analog sound … But for an audio cassette and a magnetic tape (unless, of course, it is a Japanese master tape), the characteristics of an audio CD are NOT ACCEPTABLE. For conventional studio equipment, the ability to record analog sound corresponding to AudioCD is relatively new.

Therefore, it makes no sense to digitize recordings from the pre-digital era in frenetic quality, especially those made on magnetic media. They do not contain those spectra and the amount of information that containers can store without compression.

Everything fits in MP3: digital

Strictly speaking, with most digital recordings, the image is the same. In the 90s and later, cheap plastic boomboxes appeared. The sound engineers had to take care of the uniform sound on all devices: the dynamic range of the recordings was reduced to 10-12 bits.

One more point. Until recently, no one recorded in a very high-quality studio. Because it is difficult to work simultaneously with several dozen audio tracks with high recording quality, and sometimes there are simply not enough human and technical resources.

Why mp3 is enough for you, but Lossless is not necessary

Did you finish the greenhouse? So you don’t need to lose, listen to high quality mp3.

Very often there are people who, in principle, despise compressed formats. You should not be guided by your opinion. The following mods that in the studio with a 90% probability will not hear the difference between compressed and uncompressed audio.

What is mp3

MP3 isn’t just about cutting quality. It was developed by the Fraunchhofer Society, an association of applied research institutes in Germany. Later they came up with AAC, which could become the main compressed audio format … But it didn’t work.

Did you know that MP3 comes with variable (VBR) and constant (CBR) bit rate? The constant bit rate, due to the operation of the algorithm, is encoded each time as the first. Therefore, it can produce uneven quality, which means that not all sounds in this situation will be recorded in high quality.

Since MP3 has been around for a long time, it has many limitations. Bit width is 16-24 bits. The sample rate is represented by the following set of options: 8; 11,025; 12; sixteen; 22.05; 24; 32; 44.1; 48. The maximum bit rate does not exceed 320 kbps. The maximum number of channels is 2. But we are still talking about music, we still have to search for multi-channel recordings.
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Now let’s see how MP3 is encoded. The illustration shows the time-frequency distribution of sound. Same recording: Audio CD, OGG file, MP3 well encoded. What we observe is that the pieces on the right and left almost completely coincide. This means that the MP3 file sounds almost the same as the original CD recording.

Human hearing and its limits – psychoacoustics

The fact is that the main task of the Fraunchhofer Society is the development of psychoacoustic models of human perception of sound. And here are many subtleties. The main thing is that we are not dolphins.

Second, there are certain restrictions on the number of sounds perceived simultaneously. A person cannot simultaneously hear more than 250 sounds of 24 ranges (in addition, the number of simultaneous sounds in the range is also quite small).

Third, the audible range is 16 Hz to 20 kHz and at the age of 60 it is reduced by almost half. Ideally, and during training (yes, you have to train it!).

All frequencies below 100 Hz are perceived not by the hearing cells, but … by the skin. Then the low waves are reflected in the ear canal; these waves are perceived as infrabass. (This is from the bone conduction area).
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Also, the number of cells that register acoustic waves is different for each one. But what is there? For each individual, their number in the right and left ear is different.

By the way, the perception of each ear is different. Change channels of your favorite song – get a new sound.

If you dig deeper, it turns out that each sound frequency is perceived only at a certain volume. When it is reached, the silence is replaced by a sharp and quite different sound. After that, a person can hear a lower sound of this frequency.