Dynamic earphones are divided into open, semi-open and closed earphones according to the degree of openness. Most earphone earplugs are moving coil earphones. The principle is similar to that of ordinary speakers. The coil in the permanent magnetic field is connected to the diaphragm, and the coil drives the diaphragm to sound under the signal current.
①Open earphones generally have a natural sense of hearing and are comfortable to wear. The hifi earphones that are commonly used at home can leak sound, and vice versa, the outside sound can also be heard. The earphones have less pressure on the ears.
②Semi-open: 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.
③Closed 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, which is more common in the professional monitoring field.
Impedance: 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 flow, capacitance and inductance 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: 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 earphone The easier it is to sound, the easier it is to drive.
Frequency response (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. Mature earphone technology has reached this requirement. .
Sound quality 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
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.
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 extend to 40hz, while a large subwoofer can extend to 16hz.
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.