Detailed knowledge of HiFi headsets

1. How are headphones classified?
1. According to the principle of transducer (Transducer) points

Mainly there are two categories of dynamic and electrostatic (ElectrostaTIc) earphones. Although there are several types of equal magnetic type in addition to these two types, they have either been eliminated or used for professional purposes. The market share is very small. , Do not discuss here.

Principle of dynamic headset:

At present, most (approximately more than 99%) earphone earplugs are of this type. The principle is similar to that of ordinary speakers. The coil in a permanent magnetic field is connected to the diaphragm, and the coil drives the diaphragm to sound under the signal current.

Electrostatic headphones:

The diaphragm is in a changing electric field. The diaphragm is extremely thin and accurate to a few micrometers (currently the diaphragm of STAX's new generation of electrostatic earphones is accurate to 1.35 micrometers), and the coil drives the diaphragm to make sound under the electric field force.

2. According to the degree of openness

Mainly open, semi-open, closed (closed)

Open earphones: The general hearing is natural and comfortable to wear. HiFi earphones that are commonly appreciated at home, the sound can be leaked, and vice versa, the outside sound can also be heard. The earphones have less pressure on the ears.

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

Closed type: The earmuffs put a lot of pressure on the ears to prevent the sound from entering and exiting, and the sound is correctly positioned and clear. This is more common in the professional monitoring field. However, this type of headphones has a disadvantage of serious bass sound.

3. According to the purpose

Mainly home (Home), portable (Portable), monitor (Monitor), mixing (Mix), human head record (Binaural　Recording)

2. What are the meanings of some related parameters and sound quality terms of headphones?

1. Headphone related parameters

Impedance: Pay attention to the difference between resistance and 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 It 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.

Sensitivity (SensiTIvity): 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, the lower the impedance, the earphone The easier it is to make a sound, the easier it is to drive.

Frequency Response (FrequencyResponse): 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. The current mature earphone technology has reached this requirement. .

2. Sound quality evaluation terms

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

Sound dyeing: The opposite of the natural neutrality of music, that is, the sound has some characteristics that the program does not have. For example, the kind of sound obtained by speaking into a jar is a typical sound dyeing. Sound coloration indicates that some components are added (or reduced) in the reproduced signal, which is obviously a kind of distortion.

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 noise, often expressed in decibels. The higher the signal-to-noise ratio of the device, the less noise it produces.

Air: An acoustic term used to express the openness of the treble, or the space between the instruments in the sound field. At this time, the high frequency response can be extended to 15kHz-20kHz. Antonyms include "dull" and "thick".

Low frequency extension: Refers to the lowest frequency that audio equipment can reproduce. It is a scale used to determine how deep a sound system or speakers can dive when reproducing bass. For example, the low frequency of a small subwoofer can extend to 40Hz, while a large subwoofer can dive to 16Hz.

Bright: refers to highlight the high frequency range of 4kHz-8kHz, when the harmonics are relatively stronger than the fundamental wave. Brightness itself is not a problem. Live concerts all have bright sounds. The problem is that they are bright enough to be well controlled. Too bright (or even howling) is annoying.
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