【 Weak current College 】 audio technology law and effect-14--Power By 【 China power house network 】

1. the frequency domain of subjective feeling

Frequency domain most important subjective feeling tone, like loudness as tone is also a kind of subjective mental capacity of the hearing, it is the level of hearing judge voice tone.

Psychology of tone and music scales is the difference between the former is a pure tone, while the latter is the music that combined the pitch of the voice. Composite sound tones not merely frequency resolution, is also the role of the auditory nervous system, listen, listen and experience and learning.

2. the time domain of subjective feeling

If the length of the sound over approximately 300ms, increase or decrease the length of time that the sound on auditory threshold change has no effect. For the pitch of the sound of feeling and the length of time. When sound duration is very short, did not recognize your voice, just hear "a la". Sound duration lengthen, you can have the tone of the feeling, only sound continuously for more than 10 MS, feeling tone to stability.

Time domain characteristics of another subjective feeling is echo.

3. spatial domain of the subjective feeling

Human ear ears listening than using single-ear listening has obvious advantages, its high sensitivity, listen to the valve, the sound source with a sense of direction, and has a strong anti-interference ability. In stereo, with speaker and stereo headphone listen and get a sense of space is not the same, the former sound seems to be located in the surrounding environment, and the latter hear sound position at the head of the Interior, in order to distinguish these two kinds of space, the former is referred to as directed, the latter is called localization.

4. hearing of Weber's law

Weber's law indicates that the person hearing the sound of the subjective experience and objective stimulation amount proportional to the logarithm of a. When the voice is small, increasing Sonic amplitude, the humanear's subjective experience increased a lot larger volume; when the sound intensity is greater, increasing the same Sonic amplitude, ear subjective experience significant increases of the volume is small.

According to the human ear in the listening, the volume control on the design circuit require exponential type potentiometers as volume control, so that uniform Rotary potentiometers turn handle, the volume is linear increase.

5. hearing of Ohm's law

Famous scientist ohm electrical was discovered, at the same time in the Ohm's law, he also discovered the human auditory Ohm's law, on the law of disclosure: ear hearing only the sound of all sounds in frequency and intensity, and the distinction between independent sound phase. According to this law, the sound system to record, replay, process control can not go to consider complex sounds in the min audio phase relationship.

Ear is a frequency Analyzer, you can convert the homophonic in tremolo, ear to frequency resolution sensitivity is high, at this point the ear than eyes high resolution, the human eye cannot see the white colour of light weight.

6. masking

Environment in other sound makes listening to a voice of listening, referred to as cloaking. When a sound intensity far louder than the other, when a certain level and that two sounds at the same time, people can only hear the sound of the voice and unnoticeable another sound exists. Masking and masking the sound of the sound pressure, masking the sound of the sound pressure level increases, the amount of increase as cloaking. In addition, the low-frequency sound masking range is greater than the range of high frequency sound masking.

Ear of the auditory characteristics to design reduce noise circuits provide important insights. Tape playback, so the listening experience, when the music and sounds in continuous change is large, we will not hear the noise floor of tape, when the music ends (blank section of the tape), it can feel to tape the "' ..." noise exists.

In order to reduce the noise impact on program sound, signal to noise ratio (SN) concept, which requires that the signal strength than the noise intensity enough big, so listen would not have felt the presence of noise. Some of the noise reduction system is the use of masking effect of the principle of design.

7. dual ear effect

Binaural effect principle is this: If sound comes from listening to the front, as the sound source to the left and right ear, so the same distance from the left and right ear sound waves reach the time difference (phase), tone difference is zero, you feel that the sound comes from listening to the front, and not biased towards one side. Sound intensity, you can feel the noise source and listen to.

8. Haas effect

Test proves: Harris in two sound sources at the same time, the sound, a sound source with another sound source of delay quantity, binaural listening experience is different and can be divided into the following three scenarios to illustrate:
(1) two sound sources in a sound source with another sound source of delay amount within 5 ~ 35mS as if the two sound sources into one, listen and can only feel ahead of the existence of a sound source and direction, not another sound source.
(2) If a sound source delay another sound source 30 ~ 50mS, already feel two acoustic source exist, but the direction is set by the leading.
(3) If an amount greater than the sound source delay another sound source is 50mS, you can feel the two sound sources at the same time, direction of individual sound sources to determine the latency is clear and echo.
Haas effect is stereo system one directional basis.

9. de? wave El effect

De? wave El effect is stereo system directed another Foundation. De? wave El effect is: placed left and right channel two speakers, listen to two speaker symmetric line listen and give two speakers-infeed different signal,you can get the following findings:
(1) If you give two speakers into the same signal, that is, the intensity levelPoor Δ L = 0, t = 0 Δ time difference, you only feel a sound, and from two speakers on the line of symmetry.
(2) if the only speaker of intensity differentials Δ L is not 0, you listen and feel the sound preference more loud a sound box, if the intensity differentials Δ L is greater than or equal to 15dB, feel the sound entirely from a sound that only speakers.
(3) if the intensity differentials Δ L = 0, but the time difference of the two speakers Δ t is not 0, you feel the sound to be reached by the speaker orientation. If the time difference is greater than or equal to Δ t 3ms, feel sound entirely from first arrived only speaker orientation.

10. Lloyd's effect

Lloyd's effect is a stereo range of psycho-acoustic effects. Lloyd's effect revealed: If the delay of signal then RP superimposed on direct-to-signal, will produce a clear sense of space, the sound seems to come from all directions, listen to it in the band.

11. Keyhole effect

Mono recording system using a microphone recording signals in a track, all the way to the amplifier is used for playback and a speaker, the sound source is a point source, like listening to through the door of the keyhole to listen to the Interior of the Symphony, this is the so-called Keyhole effect.

12. bathroom effect

Confront the bathroom there is a personal feel and the sound in the bathroom, the reverberation time is too long and too much, this phenomenon in the electroacoustic technology sound effect called bathroom in the description. When a low, intermediate frequency, resonance, exaggeration of the frequency response is flat, 300Hz lifting excess, bathroom effect.

13. the Doppler effect

Doppler effect reveals mobile sound for listening features: when the sound source and listen to the relative motion between, will feel a frequency determined by thesound of his voice changed when the sound source to listen who approached is frequency at a slightly higher pitched, when the sound source left is slightly lower tone frequency. The frequency of change called Doppler frequency shift. Closer to the sound source in listening to the same distance than does not move when the intensity is high, and remove the source of strength to smaller, often sound source to the direction of movement.

14. likai test

Likai test proves: two sound sources in phase contrast, sound like you can out of two sound sources, or even jump to listen.

Likai test also prompts, as long as proper control of two sound sources (left and right channel speakers) intensity, phase, you can access a wide range (rotation, depth) of the mobile field.