Briefly describe the types and characteristics of speakers and speakers
1. Types and characteristics of speakers
There are many types of speakers, which can be simply divided into cone speakers, dome speakers, horn speakers, flat speakers, piezoelectric speakers, and so on. Among the professional speakers are mainly paper cone speakers, dome speakers and horn speakers.
(1) Paper cone speaker The diaphragm of the paper cone speaker is cone-shaped, and most of the cone diaphragm is paper, so it is also called cone speaker. It is composed of three parts: diaphragm system, magnetic circuit system and auxiliary system.
The directivity of the paper cone speaker, because the cone can be regarded as piston vibration in the middle and low frequency bands, when the cone size is smaller than the wavelength, the sound radiation is non-directional; as the frequency increases, the directivity becomes more and more obvious , The smaller the diameter of the paper cone, the better the high-frequency directivity. The high-frequency directivity of the cone speaker is related to the half apex angle of the cone. The smaller the half apex angle, the deeper the depth of the cone, and the high frequency components radiated by the root of the cone will be limited to a very narrow angle. The directivity becomes sharp. In order to improve the high-frequency directivity, the half-angle is often made larger. In professional audio, we usually use the cone speaker as a low-frequency or mid-frequency unit.
(2) Dome speaker The diaphragm of the dome speaker is in the shape of a dome. This kind of loudspeaker has the characteristics of wide playback frequency, good directivity, good transient characteristics, good phase characteristics and low distortion; but the working efficiency of the loudspeaker is low, and it is difficult to make it larger from the structural point of view. The general dome-shaped loudspeaker The diaphragm is less than 5 inches. Because the diaphragm is small, its high frequency characteristics are better, and it is generally used for the tweeter or midrange unit of high-fidelity home audio or professional monitor speakers.
(3) Horn speaker The horn speaker radiates sound waves to the surrounding medium through a horn, which is a kind of indirect radiation. The horn loudspeaker includes a driving unit and a horn part. Its diaphragm has two types: spherical and anti-spherical. The vibration of the diaphragm is coupled with air through the horn to radiate sound energy. Its biggest advantage is its high efficiency. The nonlinear distortion is usually smaller than that of a cone speaker, and it has sharp directivity. The disadvantage is that the playback frequency is relatively narrow, which is suitable for the mid- and high-range units in professional audio.
2. Types and characteristics of speakers
(1) Airtight professional speaker The airtight professional speaker is a fully enclosed speaker. This kind of speakers is popular in Europe and America. It completely isolates the sound waves radiated from the back of the speaker in the speaker box, eliminating acoustic short circuit and interference. However, the vibration of the paper cone will compress and expand the air in the box. If the thickness of the speaker panel is not enough, it is easy to produce vibration and affect the sound clarity. The resonant frequency of a closed speaker is directly proportional to the resonant frequency of the speaker. To obtain lower frequency sound reproduction, it must be achieved by increasing the diameter of the speaker and reducing the resonant frequency of the speaker. At the same time, the size of the cabinet also directly affects the quality of the sound. The biggest advantage of the closed professional speaker is the simple structure of the cabinet, convenient debugging, easy design and production, and soft sound tone, which is suitable for high-fidelity speaker production. The disadvantage is that the cabinet is large and the use efficiency is low.
(2) Inverted professional speaker The inverted professional speaker is currently the more popular speaker. It uses the radiated sound wave from the back of the speaker to pass through 1 to 2 inverted holes on the cabinet, and reverse the phase of the sound wave by 180 degrees to realize the sound wave inversion. The superimposition of the phase and the sound radiated by the loudspeaker in the forward direction improves the low frequency use efficiency of the loudspeaker. Its characteristic is to increase the low-frequency radiation sound pressure and the lower limit frequency of low-frequency reproduction, and it also has the characteristics of small cabinet and low distortion. The disadvantage is that the design structure is complex and difficult to manufacture.
(3) Horn-type combination speaker The horn-type combination speaker is a horn-type speaker with wood or plastic added to the front of the speaker cone. The purpose of making horn-type professional speakers is to improve the directivity of the speakers, so that the speakers have a sufficiently large mixing radius, and the smaller the horn angle, the better the directivity. Strong directivity speakers are mainly used in the main sound reinforcement system of a large professional sound reinforcement system.