1, the type of headphones
Headphones are classified according to their switching modes, mainly moving coil, electrostatic and isomagnetic. Separate from the structure, semi-open and closed. From the wearing form, there are earplugs, earhooks and headbands.
2, the difference between open and closed headphones
The open earphone's outer casing is open, and the open earphones are light in weight, natural in sound, and free from stress. Because it is open, the sound is leaked, and external noise will enter. Semi-open headphones means that the opening of the headphones is selective, that is, only certain frequencies are open to other frequencies, or are 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 details are rich, and the low frequency response is very good. For most people, the closed earphones are tightly sealed.
3. What is a high-fidelity headset?
The main performance of the International Electrotechnical Commission IEC581-10 standard high-fidelity headphones is: frequency sound is not lower than 50Hz to 12500Hz; the allowable error of typical frequency response is ±3dB; the slope of the frequency response curve does not exceed 9dB without octave at 250Hz-800Hz The difference between the average sound pressure level of the inner left and right units in the same octave bandwidth is not more than 2dB, and the harmonic distortion is not more than 1% when the sound pressure level is 94dB in the range of 100Hz-5000Hz, and not more than 3% at 100dB; The frequency response is allowed to decrease between 2KHz and 5KHz to improve transparency and space.
4. What is the frequency response range of the headphones?
Frequency Response (Frequency Response): The sensitivity value corresponding to the frequency is the frequency response. The image is the frequency response curve. The range of human hearing can reach 20Hz-20000Hz. The mature earphone technology has reached this level. Claim. The frequency response range refers to the width of the frequency band that the earphone can deliver. The excellent earphone frequency response width can reach 5Hz-40000Hz, while the human ear's hearing range is only 20Hz-20000Hz. It is worth noting that the criteria for defining the frequency response width are different, for example, 1/2 or lower than the average output amplitude, which is obviously different. The average manufacturer is to reduce the output amplitude by 1/2 to the standard measured frequency response width, which is to say -3dB as the standard, but because of the different test standards used, some products are measured at -10dB. This is actually equivalent to a standard measurement below 1/16 of the normal value. Therefore, the width of the frequency response is greatly widened. When purchasing, users should pay attention to the frequency response width of different brands of headphones may have different test standards.
5. What is the impedance of the headphones?
Impedance: Pay attention to the difference between the meaning of the resistance. 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 It also hinders the flow of current. This effect is called reactance, and the impedance we use everyday is the sum of the resistance and the reactance in the vector. On machines with headphone jack output such as desktop or amplifier, VCD, DVD TV, etc., it is generally suitable to use medium and high impedance headphones. If you use a low-impedance earphone, you must first turn down the volume and then plug in the earphone, then adjust the volume a little bit to prevent the headphone from overloading. The earphone is burnt out or the voice coil is deformed and misplaced to cause breakage. The impedance of the earphone is generally easier to push. Therefore, portable and power-saving machines such as Walkman should choose low-impedance headphones, but also pay attention to high sensitivity. Sensitivity indicators are more important for the Walkman.
6. What is the harmonic distortion of the headphones? The output of the device does not fully reproduce its input, resulting in distortion of the waveform or an increase or decrease in signal components. Harmonic distortion is a kind of waveform distortion, which is marked in the earphone index. The smaller the distortion, the better the sound quality.
7. What is the sensitivity of the headphones? Sensitivity: The sound pressure level that the earphone can emit when the input power of 1 mW is input to the earphone (the unit of sound pressure is decibel, the louder the sound pressure is, the higher the volume), so the higher the sensitivity, the smaller the impedance, the earphone The easier it is to sound, the easier it is to drive. Generally speaking, the sensitivity of the earphone refers to the amount of power that needs to be input in the same case here, and the higher the sensitivity, the smaller the input power required. For portable devices such as Walkman, sensitivity is a very important indicator. Of course, for desktops, this indicator is relatively less important.
8, the impact of wire on the sound of headphones. Most earphone cables are made of copper. The general purity (usually expressed by a few N, such as 4N, 6N??) is higher, the better the conductivity, the smaller the signal distortion, the common ones are: TPC (electrolytic copper): purity 99.5% OFC (oxygen-free copper): purity 99.995% LC-OFC (linear crystal oxygen-free copper or crystalline oxygen-free copper): purity above 99.995% OCC (single crystal oxygen free copper): highest purity at 99.996% Above, it is an indisputable fact that PC-OCC and UP-OCC wires are affected by the sound of headphones. In the HI-FI system, different signal lines and speakers obviously change the characteristics of the sound. The earphones are no exception. In recent years, several wires have been introduced abroad, which provide conditions for HD580 and 600 to change the wires. The famous wires are as Clou in Sweden and Kada in the United States.
9. Under what circumstances should I equip my headphones with an amplifier? There are three kinds of situations for the ear amplifier. One is the sound source used. For example, there is no earphone dedicated output jack on the CD/DVD player. At this time, a headphone amplifier can be equipped to output from the audio line of the CD/DVD player (LINE OUT). Use two signal wires to connect to the audio input jack of the amplifier. In the second case, a low-sensitivity, high-impedance earphone, if you can't push it with an existing audio source such as a Walkman, you should also purchase a headphone amplifier. The third case is a medium-to-high-end earphone. The introduction of such an earphone with the existing headphone jack can not exert the potential of the earphone. Adding a headphone amplifier can further improve the sound quality. In this case, we should consider adding A high quality headphone amplifier.
10, tube tube headphone amplifier cargo transistor headphone amplifier how to buy? At present, the tube amplifier power amplification on the market uses a female output device as the final power amplifier. This type of circuit structure should be said to be very reasonable. Therefore, it is adopted by most manufacturers. However, this circuit has a high output impedance and can only be used with headphones of 200 or more ohms, and the higher the impedance, the smaller the distortion. The final stage of the power amplifier of the transistor earphone adopts an OTL circuit, and the impedance requirement is not strict, and the lower the impedance, the larger the output current and the greater the power. Therefore, the transistor power amplifier is high, medium and low impedance, but it is better to push the medium and low impedance headphones.
11, the sound characteristics of the headphones Everyone is more familiar with eating than the headset, then we start from eating. Sichuan flavor is spicy, Cantonese tastes light and fresh, and Shanxi people are sour. What are the three flavors that taste the best? I am afraid that different people have different opinions. The characteristics of the headphones are the same. European headphones such as Baia, Sennheiser, AKG, roughly similar sound, true, clear, light as water. American headphones such as Gauss, Alice, and Goethe make people feel passionate, human, and energetic. Japanese headphones have the aesthetic characteristics of the East, beautiful voice, warm voice, high and low frequency extension, some people describe the sound like LS 3/5a What music do you like, what headphones, you are young or middle-aged, what character, hobby You decide, from the characteristics of the sound, the above three types have only different characteristics, and there is no difference between good and bad.
12. Headphone sound quality evaluation terminology: The range between the highest and lowest sounds of a musical instrument or human voice. Tone: Also known as a sound, one of the basic attributes of sound, such as erhu and pipa, is a different tone. Sound Dye: The opposite of the natural neutrality of music, that is, the sound is dyed with some features that the program itself does not have. For example, the sound that is heard in a jar is a typical sound. The sound dye indicates that some of the components are added (or reduced) in the reproduced signal, which is obviously a distortion. Distortion: The output of the device cannot fully reproduce its input, resulting in distortion of the waveform or an increase or decrease in signal components. Dynamic: Allows you to record the ratio of the largest message to the smallest message. Transient response: The ability of the equipment to follow burst signals in music. The equipment with good transient response should respond immediately when the signal comes, and the signal will stop when it stops, and it will never drag the water. (Typical instrument: piano) Signal-to-noise ratio: Also known as the signal-to-noise ratio, the useful components of the signal are compared with the strength of the noise, often expressed in decibels. The higher the signal-to-noise ratio of the device, the less noise it produces. Air Sense: An acoustic term used to indicate the treble or the spatial separation between instruments in the sound field. At this time, the high frequency response can be extended to 15 kHz to 20 kHz. The antonyms are "dull" and "thick". • Low frequency extension: refers to the lowest frequency that audio equipment can reproduce. It is used to determine the extent to which the sound system or speaker can dive when replaying the bass. For example, a small subwoofer can have a low frequency extension of 40 Hz, while a large subwoofer dive to 16 Hz. Bright: refers to highlighting the high frequency range of 4kHz-8kHz, where the harmonics are relatively stronger than the fundamental. There is nothing wrong with the brightness itself. The live concerts have bright sounds. The problem is that the brightness is well controlled, and the brightness is too bright (or even whistling).
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