48 views Yuda Electronic (HK) Technology Co.,Limited. 2019-03-29
Relevant medical data show that when the volume heard by the human ear exceeds 85 decibels, the longer time can cause hearing fatigue; when the volume is above 110 decibels, it is enough to cause the hair cells of the human ear to die. It can even cause irreversible hearing loss. The volume output of the headphones is generally around 84 decibels, and some high frequency ranges can reach 120 decibels. This volume has a great stimulating effect on the ear nerves, causing hearing loss for a long time, and severe deafness and neurasthenia.
First appeared is the high frequency hearing loss, and the language frequency used in our daily communication has not been affected, so it is often overlooked in the early days. Only when the hearing loss extends to the low frequency and the hearing loss reaches a certain level, the hearing impairment will occur, which will affect the language communication and social activities. Therefore, the impact of using headphones can usually be manifested after many years.
The difference between open headphones and closed headphones
The open sports earphone’s outer casing is open, and the open earphones are light in weight, natural in sound and non-pressure. Because it is open, the sound is leaked, and outside noise will enter.
Semi-open headphones means that the opening of the headphones is selective, open only to certain frequencies, closed to other frequencies, or open in a certain direction and closed in other directions.
The outer casing of the enclosed earphone is closed to prevent external sound from entering, and the sound leakage is reduced, which is used in professional monitoring. The sound is generally very clear, the low frequency response is very good, for most people, closed headphones have a good texture.
What is the frequency response range of the headphones?
Frequency response: The sensitivity value corresponding to the frequency is the frequency response. The image is the frequency response curve. The range that human hearing can reach is about 20Hz-20000Hz. The production process of the mature phone headset production suppliers has reached this requirement.
What is a high fidelity headset?
The frequency response is not less than 50Hz to 12500Hz; the allowable error of the typical frequency response is ±3dB;
The frequency response curve of two headphones (such as stereo) corresponds to the difference between the average sound pressure level of each frequency (the center frequency is in the range of 250~~8000Hz) and the bandwidth should not be greater than 2dB;
In the range of 100Hz-5000Hz, when the sound pressure level is 94dB (based on 20uPa), the harmonic distortion does not exceed 1%, and does not exceed 3% at 100dB;
The frequency response of the headphones is allowed to drop between 2KHz and 5KHz to improve transparency and space.
What is the impedance of the headphones?
Impedance: Pay attention to the difference between the meaning of the resistor. In the world of direct current (DC), the effect of the object on the current obstruction is called resistance, but in the field of alternating current (AC), in addition to the resistance will block the current, the capacitance and inductance will also hinder. The flow of current, this effect is called reactance, and our daily impedance is the sum of the resistance and the reactance in the vector.
What is the harmonic distortion of the headphones?
Harmonic distortion is a kind of waveform distortion, which is marked in the earphone index. The smaller the distortion, the better the sound quality.
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