Audio technology and effect of the law of 14

Number of visits: Date:2016-04-13

Subjective feeling 1. Frequency Domain

The most important subjective feeling is that the frequency domain pitch, loudness like the same amount of subjective psychological tone is also a hearing, it is the judge hearing the sound level of the tone property.

Scale difference between psychology and music is tonal, the former is a pure tone sound, which is the music of such complexes tone of voice. Composite tone of voice is not simply the frequency analysis, but also the auditory nervous system is affected by a listener listening experience and learning.

2. Time domain of subjective feeling

If the time length of the sound exceeds about 300ms, then increase or decrease the length of time the sound of the hearing threshold change does not work. For feeling tone also sounds length of time. When the sound duration is short, not to listen to the tone, only heard "rattling" sound. Longer duration of the sound, in order to have a feel pitch, only the sound sustained tens of milliseconds or more, the feeling tone to stabilize.

Another characteristic of the subjective feeling of the time domain echo.

3. The subjective feeling of spatial domain

Ear binaural listening with ears than the single tone has obvious advantages, its high sensitivity, low valve to listen for the sound source with a sense of direction, and a relatively strong anti-interference ability. In stereo condition speaker stereo headphones with a sense of space and get listening is not the same, the former seems to hear voices in the surrounding environment, and the latter to hear the voice inside the head position, in order to distinguish between these two sense of space, the former as directed, which is called positioning.

Weber's Law 4. The hearing

Weber's law states that the amount of the subjective feelings of the human ear sound and objective stimulating amount proportional to the logarithm relationship. When the sound is small, acoustic amplitude increases, the subjective feelings of the human ear volume increase amount larger; when the sound intensity is large, the same acoustic amplitude increases, the subjective feelings of the human ear volume increase amount is small.

According to the characteristics of the human ear listening, in the design of the volume control circuit requires exponential potentiometer as a volume control, so that even when the rotary potentiometer turn knob, the volume is linearly increasing.

5. The hearing of Ohm's law

Scientists discovered the famous Ohm Ohm's Law in electricity, he also discovered the Ohm's law on human auditory, this law reveals: the human ear hearing only the sound of each crossover frequency and intensity, but not with sub phase between unrelated sounds. We can not consider the phase relationship of each crossover complex sounds under the control of the law, sound system in the recording, reproduction and other processes.

The human ear is a frequency analyzer, homophonic polyphony of each can be separated from the human ear frequency resolution, high sensitivity, in this high resolution Exalted ear than the eye, the human eye can not see the white light of the various color light components.

6. masking effect

Other sounds in the environment cause the listeners to a particular sound of hearing loss, which is called masking. When the intensity of a voice louder than the other, to a certain extent when these two voices exist, one can only hear the sound of the voice exist, and another voice imperceptible presence. Acoustic masking quantity and the masking sound pressure related to the masking sound pressure level increases, the amount of masking increases. In addition, the low frequency sound masking range greater than the range of high-frequency sound masking.

This auditory characteristics of the human ear to noise reduction circuit design provides an important inspiration. Tape playback, there is such a listening experience when music program in continuous change and louder, we will not hear the noise floor of the tape, but when the music program ends (para blank tapes) when, can feel to tape "hiss ......" noise is present.

To reduce the impact of noise on voice program proposed noise ratio (SN) concept? Which requires sufficient signal strength than the strength of the big noise, so listeners will not feel the presence of noise. Some noise reduction system is designed using the principle Masking made.

7. Binaural effect

The basic principles of binaural effect is this: if the sound comes from the front of the listener, since the sound source to the left this time, the distance is equal to the right ear, so that sound waves reach the left and right ear time difference (phase difference), the tone difference zero, and feel the sound from the front of the listener, rather than favor one side. Sound level is not the same, you can feel the distance between the sound source and the listener.

8. Haas effect

Haas tests showed that: two sound sources at the same time the sound, the delay amount according to a source with another sound source is not the same feeling listening ears are different, can be divided into the following three cases to illustrate :

(1) two sound sources in a sound source and another source of delay in the amount of time within 5 ~ 35mS, as if the two sound sources into one, the listener can feel ahead of a sound source the presence and direction, do not feel the presence of another sound source.

(2) If a sound source delay another sound source 30 ~ 50mS, has been able to feel the presence of two sound sources, but still leading the predetermined direction.

(3) if a delay greater than the sound source is a sound source other 50mS, then feel the simultaneous presence of two sound sources, each direction is determined by the sound source, the sound is clear hysteresis echo.

Haas effect is one of the foundations stereo system orientation.

9. De Boai effect

De Boai effect is the basis of another stereo system orientation. Experimental de Boai effects are: Place the left and right channel two speakers, two speakers at the listener symmetrical line listening to two speakers fed different signals can be obtained the following conclusion:

(1) if the two speakers fed the same signal that the intensity level difference ΔL = 0, the time difference Δt = 0, this time just felt a voice, and the line of symmetry from two speakers.

(2) If the two speakers of the intensity level difference ΔL is not zero. The listener feel the sound of a loud speaker biased, if the intensity level difference ΔL than or equal to 15dB, this time feel the sound entirely from a loud speaker that a .

(3) If the intensity level difference ΔL = 0, but the two speakers of the time difference Δt is not 0, then it would only feel the sound move to the direction of the speaker before arrival. If the time difference Δt than or equal to 3ms, the feeling of the sound entirely from the direction of the bird speaker arrives first.

10. Lloyd's effect

Lloyd's effect is a psychoacoustic stereo effect one kind of range. Lloyd's effects reveals: If the signal is delayed and inverted again superimposed on the direct signal will produce a clear sense of space, the sound seemed to come from all directions, the listener feel like being in the band being.

11. Keyhole Effect

Monaural recording systems use a microphone recording signal recorded on a track, all the way to playback when using an amplifier and a speaker, so the reproduced sound source is a point source, like listening through the door on the spoon hole listening room and the symphony, which is the so-called keyhole effect.

12. Bathroom effect

When there is a personal experience and proximity to the bathroom, the sound of the bathroom, the reverberation time is too long and excessive, a phenomenon known in the bathroom sound effects described electro-acoustic technologies. When the low-IF certain exaggeration, there is a resonance frequency response is not flat, 300Hz when lifting excess occurs bathroom effect.

13. Doppler effect

Doppler effect reveal about the nature of mobile listening sounds: when there is relative motion between the sound source and the listener will feel a certain frequency determined by the pitch of their voices changed, when the sound source close to the listeners when the frequency is slightly higher pitch when a sound source is leaving little to reduce the frequency of the pitch. The amount of change in frequency is called doppler shift. The strength of the sound source closer to the listener than the same distance in the moving distance does not produce a large, but the intensity of the excitation source is removed to be smaller, the moving direction of the sound source is typically concentrated.

14. Lee test

Lee test showed: two phase opposite sound source, audio and video can exceed beyond two sound sources, and even skip listening behind.

Lee also suggested that test, twice as long as the proper control of the source (left and right channel speaker) of the intensity, phase, you can get a wide range (angle, depth) panned field.

TypeInfo: Sound Knowledge

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