Hi-Fi is the abbreviation of English High-Fidelity, literally translated as "high fidelity", and its definition is: a replayed sound that is highly similar to the original sound. So what kind of audio equipment's playback sound is Hi-Fi? So far it is still difficult to draw a definite conclusion. Professionals in the audio industry rely on various instruments and various means to detect various indicators to determine the level of Hi-Fi equipment, while audio enthusiasts often use their ears to determine whether the equipment meets the Hi-Fi in mind. . To judge the high-fidelity of the reproduced sound, not only high-performance equipment and software, but also a good listening environment are required. Therefore, how to correctly measure the Hi-Fi level of audio equipment, there is still a difference between objective testing and subjective evaluation.
HiFi headset hifi headset
Hi-Fi = high fidelity. Hi-Fi systems in the mouth of enthusiasts generally refer to audio equipment with higher technical indicators. Hi-Fi is endless.
Pay attention to the difference between the meaning of 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 hindering current, capacitance and inductance also hinder current. Flow, this effect is called reactance, and what we call impedance is the sum of resistance and reactance in a vector.
The sound pressure level that the earphone can emit when the power of 1 milliwatt is input to the earphone (the unit of sound pressure is decibels, the greater the sound pressure, the greater the volume), so generally the higher the sensitivity and the lower the impedance, the easier the earphone will produce. The easier it is to drive.
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. Nowadays, mature earphone technology has reached this requirement.
Most of the earphone cables are made of copper, and the general purity (usually expressed by a few N, such as 4N, 6N...) the higher the conductivity, the lower the signal distortion, and the common ones are:
TPC (Electrolytic Copper): 99.5% purity
OFC (oxygen free copper): 99.995% purity
LC-OFC (linear crystalline oxygen-free copper or crystalline oxygen-free copper): purity above 99.995%
OCC (Single Crystal Oxygen-Free Copper): The highest purity, above 99.996%, is divided into PC-OCC and UP-OCC
1. The sound bottom is pure, without any unpleasant "hiss", "weng", "cock" sound. 2. Good balance, the sound is not too cold or too warm, the high, middle and low frequency energy is evenly distributed, and the fusion between frequency bands is naturally smooth. 3, the high frequency is extended well, delicate and supple. 4. Good low frequency response, clean and full, full of flexibility and strength, without any feeling of hypertrophy. 5. The intermediate frequency distortion is very small, full and warm, the human voice is kind and natural, thick and not exaggerated. 6. Good resolution, rich details, and small signals can be reproduced well. 7. Good sound field description ability, wide sound field, accurate and stable instrument positioning, enough information in the sound field, no feeling of hollowness. 8. There is no obvious compression in the dynamics, with a good sense of speed, no distortion or very little distortion at high volume.
Sound quality evaluation
Range: the range between the highest and lowest notes that an instrument or human voice can reach
Tone: also known as timbre, one of the basic properties of sound, such as erhu and pipa are different timbres
Distortion: The output of the device cannot fully reproduce its input, resulting in distortion of the waveform or increase or decrease of signal components.
Dynamic: Allow to record the ratio of the largest information to the smallest information
Transient response: the ability of the equipment to follow the sudden signal in music. The equipment with good transient response should respond immediately as soon as the signal comes, and stop abruptly when the signal stops. (Typical musical instrument: piano)
Signal-to-noise ratio: also known as signal-to-noise ratio, the contrast between the useful components of the signal and the strength of the noise, often expressed in decibels. The higher the signal-to-noise ratio of the device, the less noise it produces.
Airy: An acoustic term used to express the ethereal and openness of the treble, or the space between the instruments in the sound field. The high frequency performance is good, as ethereal as ice water, as if surrounded by air, it feels empty and distant. At this time, the high frequency response can be extended to 15khz-20khz.
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 speakers can be extended when reproducing bass. For example, the low frequency of a small subwoofer can be extended to 40hz, while the large subwoofer can be extended to 16hz.
There are mainly two categories of dynamic and electrostatic headphones.
According to purpose
Mainly home (Home), portable (Portable), monitor (Monitor), mixing (Mix), human head record (Binaural Recording)
According to openness
Mainly open, semi-open, closed (closed).
(1) Open style: Generally speaking, it has a natural sense of hearing and is comfortable to wear. The HIFI earphones commonly used for home appreciation can leak the sound, and vice versa, the outside sound can also be heard. The earphones exert less pressure on the ears.
(2) Semi-open type: There are no strict regulations, and the sound can only enter but not exit, or only exit but not enter, and make corresponding adjustments according to needs.
(3) Closed type: The earmuffs put a lot of pressure on the ears to prevent the sound from entering and exiting, and the sound is positioned correctly. This is more common in the field of professional monitoring. However, this type of headphones has a disadvantage that the bass is severely stained. W100 is an obvious example .