Core reminder: Hearing is people's subjective response to sound. Any complex sound can be described by three physical quantities of sound: amplitude (sound intensity or sound pressure), frequency and phase. But for the perception of the human ear, sound is described by three other quantities, namely loudness, pitch and timbre. This is what we usually call the three elements of sound

 

What is pitch: pitch

 

The frequency of a sound is called pitch, which is one of the three main subjective attributes of sound, namely volume (loudness), pitch, and timbre (also called timbre). Indicates the degree to which human hearing distinguishes the pitch of a sound. The pitch is mainly determined by the frequency of the sound, but also related to the sound intensity. For a certain intensity of pure tones, the pitch rises and falls with the rise and fall of the frequency; for certain frequencies of pure tones and low-frequency pure tones, the pitch decreases with the increase in sound intensity, while the pitch of high-frequency pure tones rises with the increase in intensity.

 

Tone definition editing

 

The height of the sound is called the pitch, and the frequency determines the pitch. When the object vibrates fast, the pitch of the sound is high.

 

The slower the vibration, the lower the pitch of the sound. The effect of tone on hearing In addition, there are several effects in the human hearing characteristics. If you do not understand these, you will not know the physiological and psychoacoustic effects that people receive in the process of listening. In response to the various effects of human hearing, "New Life for Audio and Video" specially compiled and edited this article for your reference.

 

Subjective perception in the frequency domain Everyone knows that sound is produced by vibration. The so-called sound frequency is the vibration frequency of the sound source. The sound that nature and humans may produce ranges from 1 Hz to hundreds of thousands of Hz, but not all sound wave vibrations can be heard by the human ear.

 

Frequency is the physical characteristic of sound, and pitch is a subjective reflection of frequency. Generally, the pitch level is consistent with the frequency level. The frequency remains unchanged, and the change in intensity has a slight effect on the pitch. As the intensity increases, low-frequency tones appear lower, and high-frequency tones appear higher. For example, the tone of 8192Hz sound at 100dB intensity is higher than that at 80dB, and the tone produced by 128Hz at 100dB is lower than that at 70dB.

 

Subjective perception of the time domain If the duration of the sound exceeds about 300ms, the increase or decrease of the duration of the sound has no effect on the change of the auditory threshold. The perception of tone is also related to the duration of the sound. When the sound lasts for a short time, no tone can be heard, just a "click" sound. Only when the sound lasts for more than tens of milliseconds can the tone feel stable.

 

Another subjective sensory characteristic of the time domain is echo. The subjective perception of the spatial domain Human binaural listening has obvious advantages over monaural listening. It has high sensitivity, low listening valve, a sense of direction to the sound source, and strong anti-interference ability. Under stereo conditions, the sense of space obtained with speakers and stereo headphones is different. The sound heard by the former seems to be in the surrounding environment, while the sound heard by the latter is inside the head. In order to distinguish between the two The sense of space, the former is called orientation, and the latter is called positioning.

 

The hearing of the human ear is only related to the frequency and intensity of the partial tones in the sound, and has nothing to do with the phase between the partial tones. According to this law, the process of recording and playback in the audio system can be controlled without considering the phase relationship of the partial tones in the complex sound.

 

The human ear is a frequency analyzer, which can separate the harmonics in the polyphony. The human ear has a high sensitivity to frequency resolution. At this point, the human ear has a higher resolution than the eye, and the human eye cannot see all kinds of white light. Color light components.

 

Weber's Law of Hearing Weber's Law states that the subjective amount of human hearing sound is directly proportional to the logarithm of the objective stimulus. When the sound is smaller and the amplitude of the sound wave is increased, the subjectively perceived volume of the human ear increases by a larger amount; when the sound intensity is higher and the same sound wave amplitude is increased, the increase in the subjectively perceived volume of the human ear is smaller.

 

According to the above-mentioned listening characteristics of the human ear, it is required to use an exponential potentiometer as a volume controller when designing a volume control circuit, so that when the potentiometer handle is evenly rotated, the volume increases linearly.

 

Masking effect

 

Other sounds in the environment will reduce the listener's hearing of a certain sound, which is called masking. When the intensity of one sound is much greater than the other sound, and when the two sounds exist at the same time, people can only hear the sound of the loud one, but cannot detect the existence of the other sound. The amount of masking is related to the sound pressure of the masking sound. As the sound pressure level of the masking sound increases, the amount of masking increases. In addition, the masking range of low-frequency sounds is greater than that of high-frequency sounds. Experiments have proved that human hearing has preconceived characteristics. The Haas effect is discovered by Haas, and people cannot distinguish certain phenomena of delayed sound.

 

But when two sounds of equal intensity and one of them are delayed to reach the human ear: the delay time is less than 30ms, the sound is only from the undelayed sound source; the delay time is 30~50ms, and the two can already be felt The sound source exists, but the direction is still determined by the leader; when the delay time is >50ms, the delay sound cannot be covered, and the delay will be felt as a clear echo on the auditory. The Haas effect is also one of the foundations of stereo system orientation.

 

Xunweite’s hearing aid telephone series for the elderly are based on hearing aids. Hearing aid is determined by volume and tone. Xunweite Hearing Aid Series is designed for the elderly and the hearing impaired.

 

Main products: Telephone series: hearing aid phones for the elderly, remote smart phones for help, voice phones for the blind, remote hands-free phones for the disabled, and bluetooth phones for the elderly. Auxiliary devices: vibrating phone calls, electronic alarm clocks, wireless doorbell phones Ring amplifier, hearing aid dehumidification box, portable telephone amplifier