1. Types of earphones: earphones are classified according to their energy conversion methods, mainly including dynamic, electrostatic and other magnetic types. Separate from the structure, semi-open and closed. In terms of wearing style, there are earplug style, ear hanging style and headband style.
2. The difference between open and closed earphones: the shell of the open earphone is open, and the open earphone is light in weight, natural sound, and no pressure. Because it is open, the sound leaks out, and the outside noise also enters. Semi-open earphone means that the earphone is open selectively, that is, it is only open to certain frequencies and closed to other frequencies, or it is open in a certain direction and closed in other directions. The shell of the closed earphone is closed to prevent outside sound from entering, and the sound leakage is reduced. It is used a lot in professional monitoring. The sound is generally very clear, rich in details, and low frequency response is very good. For most people, closed headphones have a sense of airtightness.
3. High-fidelity headset: The main performance of the International Electrotechnical Commission IEC581-10 standard high-fidelity headset is: the frequency response is not less than 50Hz to 12500Hz; the allowable error of the typical frequency response is ±3dB; the slope of the frequency response curve does not exceed no frequency The difference between the average sound pressure level of the unit within the same octave bandwidth within the range of 9dB within 250Hz-800Hz does not exceed 2dB. Within the range of 100Hz-5000Hz, when the sound pressure level is 94dB, the harmonic distortion does not exceed 1%, and it does not exceed 100dB. More than 3%; the frequency response of the earphone is allowed to decrease between 2KHz-5KHz to improve transparency and sense of space.
4. The frequency response range of the earphone: Frequency Response: The sensitivity value corresponding to the frequency is the frequency response, and the graph is the frequency response curve. The range that human hearing can reach is about 20Hz-20000Hz, which is currently mature Headphone technology has reached this requirement. The frequency response range refers to the width of the frequency band that the earphone can send. The frequency response width of an excellent earphone can reach 5Hz-40000Hz, while the hearing range of the human ear is only 20Hz-20000Hz. It is worth noting that the standards for defining the width of the frequency response are different, for example, it is less than 1/2 of the average output amplitude as the standard or less than 1/4 as the standard, which is obviously different. The general manufacturer measures the frequency response width with the output amplitude reduced by 1/2 as the standard, which means that the -3dB is the standard, but due to the different test standards used, some products are measured with -10dB. This is actually a standard measurement equal to 1/16 lower than the normal value. Therefore, the frequency response width is greatly expanded. When purchasing, users should note that the frequency response width of headphones of different brands may have different test standards.
5. Headphone impedance: Impedance: pay attention to the difference with resistance. In the world of direct current (DC), the effect of objects on the current is called resistance, but in the field of alternating current (AC), in addition to resistance, it will hinder In addition to current, capacitance and inductance will also hinder the flow of current, this effect is called reactance, and what we call impedance is the sum of resistance and reactance in a vector. On desktop computers or power amplifiers, VCDs, DVD TVs and other machines with headphone jack output, it is generally appropriate to use medium and high impedance headphones. If you use low-impedance earphones, you must first turn down the volume before plugging in the earphones, and then turn the volume up a little bit to prevent the earphones from being overloaded and the earphones are burned out or the voice coil is deformed and misplaced, causing the sound to break. The impedance earphones are generally easier to push Therefore, portable and power-saving devices such as Walkman should choose low-impedance earphones. At the same time, attention should be paid to high sensitivity. Sensitivity index is more important for Walkman.