1 subjective perception in frequency domain

The subjective feeling of the most important frequency domain is the tone, like the same amount of subjective loudness tone is also a kind of hearing, it is the level of the voice tone auditory attribute judgment.

The difference between the tone of the mind and the scale of music is that the former is the tone of pure tones, and the latter is the tone of a compound sound such as music. The tone of the complex sound is not only the frequency resolution, but also the function of the auditory nervous system, which is affected by the listening experience and learning.

2 subjective perception in time domain

If the duration of the sound is more than about 300ms, the length of time of the sound does not play a role in the change of the threshold value of the hearing. The tone is also related to the length of time. When the sound lasts for a short time, you can't hear the tone, just hear the "bang". The longer the duration of the sound, in order to have the feeling of tone, only the sound lasts for more than a few milliseconds, the tone can be stabilized.

Another subjective characteristic of the time domain is the echo.

3 spatial domain subjective perception

The use of binaural listening has more advantages than that of single ear. It has a high sensitivity, a low sense of hearing, a sense of direction to the sound source, and a strong anti-interference ability. In the stereo condition, a loudspeaker and a stereo headset with listening to get the sense of space is not the same, the sound seems to be located in the surrounding environment, the latter to hear the voice of the position in the head, in order to distinguish these two kinds of sense of space, the former is called directional, the latter is called positioning.

4 Weber's law

Webb's law shows that the subjective feeling of the human ear is proportional to the logarithm of the objective stimulus. When the sound is small, and the amplitude of the sound wave is increased, the volume of the subjective feeling of the human ear is larger; when the sound intensity is larger, and the amplitude of the same sound wave is increased, the volume of the subjective feeling of the human ear is smaller.

According to the characteristics of the human ear to listen to the sound, require the use of exponential type potentiometer in the design of the volume control circuit as the volume controller, such a uniform rotary potentiometer, the volume is linearly increased.

5 Ohm's law of hearing

The famous scientist discovered the ohm Ohm's law in electricity, he also found a human hearing on Ohm's law, this law reveals that about the frequency and intensity of each sound the human ear and voice, and has nothing to do with the sound phase. According to this law, the process of recording and replaying in the sound system can not consider the phase relation of each sound in the complex sound.

The human ear is a frequency analyzer, can be in the polysyllabic homophonic separate ear on the frequency resolution sensitivity is very high, at this point the human ear than the eye high resolution degree, the human eye can not see all the color light component in the white light.

6 masking effect

Other sounds in the environment can reduce the hearing of a person to a sound, which is called masking. When the intensity of a sound is much greater than that of another, and when it is to a certain degree and the two voices exist at the same time, one can only hear the sound of the sound, but not the other. The amount of masking is related to the sound pressure of the masking sound, and the sound pressure level increases with the increase of the masking sound. In addition, the masking range of low frequency sound is larger than that of high frequency sound.

The auditory characteristic of human ear provides an important inspiration for the design of noise reduction circuit. There is such a tape player, listening experience, when the music program in the continuously changing and sound, we never heard the tape, the background noise, but when the end of the music program (the blank section of the tape), you can feel the tape "hissing......" Noise presence.

In order to reduce the influence of noise on the performance of the program, the concept of signal to noise ratio (SN) is proposed, which requires that the signal intensity is larger than that of the noise intensity, so that the sound will not be noisy. Some noise reduction systems are designed using the principle of masking effect.

7 binaural effect

This is the basic principle of the binaural effect: if the sound from the front to the tone of the sound source at this time due to a distance equal to the left, right, left, right ear and acoustic time difference of arrival (phase difference), the timbre difference is zero, then feel the voice from listening to the front sound person, rather than to one side. Sound intensity is not the same time, can feel the distance between the source and the sound.

8 Haas effect

Haas's experiment proved that the sound of binaural hearing is different when the two sound sources simultaneously sound, according to the time delay of a sound source and another sound source, which can be divided into the following three situations:

The delay of a sound source two sound sources and one sound source is less than 5~35ms, just like the two sound sources be made one, listen only feel the existence and direction of advance of a sound source, do not feel the existence of another sound source.

If a sound source delays another sound source 30~50ms, two sound sources can be sensed, but the direction is still determined by the preamble.

If the time delay of a sound source is greater than that of another sound source, the sound source can be sensed at the same time, and the two sound sources can be detected simultaneously. The direction of the sound source is determined by the sound source, and the delayed sound is a clear echo.

Haas effect is one of the foundations of stereo system orientation.

9 de Poey effect

The de Poe effect is another basis for stereo system orientation. De Poe effect of the experiment is: the left and right channel two speakers, the sound of the two speakers in the symmetrical line listening to the two speakers into different signals, you can get the following conclusions: