Tag: volume normalization for linux

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Let’s talk about “musical dynamics” and “musical loudness” Part 2

The two brief examples above are to tell you that frequency content, sound pressure, and sound duration will affect people’s perception of sound volume.

That is why it is said that “loudness tends to human subjective perception”.

Since the volume is the subjective perception of people, how to quantify it?

To quantify “loudness”, the first thing you need to look at is the relationship between the frequency and the loudness of the human ear. There are two pictures below, you can read them carefully for reference:

Looking at the two images above, you will clearly see that the human ear and the human brain are not an organ that flattens the receiving frequency. It will not develop here. For the basis of loudness quantization, see the second image, there is a unit called “fon”. The phon unit is an attempt to quantize loudness. We take a 1kHz signal as an example, and it can be perceived at a volume of 40dB at 1kHz, so it is 40phon. Based on this, another unit is called a sone, 1 sone = 40phon. Both are units that attempt to quantify volume.

The international organization will be the ITU and the EBU…etc. The characteristics of the human ear, the psychoacoustics of the human brain, etc., all factors that affect loudness perception are considered together, and these factors are calculated through complicated mathematical calculations Define and standardize the reasonable loudness range for ” sound reproduction” only after statistically significant results have been obtained. Those interested can search: “ITU-R 1770 and ITU-R 1771”.

Should the rules be followed?

Of course continue! In fact, there is such a problem in Taiwan. Not to mention music, only the fourth channel and MOD, the sound level of each channel is different! The scariest thing is switching from the movie station to the shopping channel and often still being scared by the sudden volume of the shopping channel. Even radio shows have this kind of situation.

Here, you can go to Google again: “Volume War Loudness War”. All this is commonplace. This article is mainly to introduce the definition and specification of loudness.

Effects of loudness specifications

Although ITU, EBU, ISO, ANSI and other organizations have introduced loudness specifications, major music and video streaming platforms still have their own standards. However, the standards of the main platforms will continue to be around the specifications, and there will be no big or outside. When it comes to the audiovisual industry, it will generally affect these things:

Music streaming platforms: Records must meet loudness specifications at time of release

Video streaming platforms: Loudness specifications must be met when movies are released

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Let’s talk about “musical dynamics” and “musical sonority”

Where does the music we listen to come from?

Before we talk about it, it is necessary to quickly talk about the disc creation process. In principle, it can be divided into three parts: the initial stage, the intermediate stage and the later stage.

First stage: compose, arrange

Middle term: recording, mixing

Post: post mastering, distribution, marketing

Whether a piece of music is good or not can be determined at the initial stage of the arrangement. Then there is the recording. The recording process can be finding real musicians to record the sound of real instruments, or completing the melody required by the arrangement through software instruments. Then find a singer or singers to sing… and so on. This process is called recording.

The “balance” of a song is not only achieving the balance of the melody in the arrangement, on the other hand, it is leaning on the mix to make the recorded elements a harmony in listening and frequency, it is also usually necessary to coordinate It depends on where the track goes, or what the producer wants. After all, the purpose of a song or album is to become a commercial release, and the post-production and embellishment processes that need to be done are necessary.

Usually the post-mastering process will be done last. After the entire album’s timbre direction, volume adjustment and minor flaws etc. are fixed, the final mastering will be uploaded according to the loudness specifications required by each streaming platform. .

Quantify the volume and intensity of what we hear

Sometimes people equate loudness with loudness. Actually the two are different. They are different and at the same time influence each other.

Loudness can be quantified, in simple terms, it is our most used “decibel dB”. Volume, on the other hand, tends to be subjectively perceived by people. how to say? Different 75-decibel musical signals are sent out at a time, and everyone has different feelings about its loudness and volume.

Because loudness is related to three things: frequency content, duration, and sound pressure.

We played a 1000 Hz test signal for three minutes at a sound pressure of 80 decibels. Your perception of the volume of this signal will be very different from playing it for 10 seconds or 30 seconds.

Let us take two singers as an example, one of them has a more evident timbre in the mid-high frequency band, and the other has a more evident mid-low frequency band, they sing the same song, and they sing with the same key and similar sound pressure, generally in the mid-high frequency band. The sound of the sound will feel stronger.