Working principle: electromagnetic (reed), piezoelectric (crystal or ceramic), electrostatic (capacitive) speakers, electric (moving coil).
Effective Frequency: Bass, Middle, Treble, full-range and so on.
Diaphragm structure: cone, dome-shaped, flat-shaped Young.
Extension efforts, the high frequency top of the application of small-caliber lightweight diaphragm means to get a better solution, but the low frequency the lower end of the replay still need the help of heavy box cavity. Can promote heavy burst of sound pressure level of the loudspeaker diaphragm in the low frequency end of the volume of air volumetric flow rate is the product of the diaphragm radiation speed and area, so the smaller diaphragm if the movement distance of the longer --- - stroke, the same available to the large cone low-frequency sound pressure level, issued by the deep and powerful bass. To get the best bass performance, low-frequency speaker With a box to work properly. Speaker appearance varied, the most common is a rectangular box structure, the main categories of closed boxes, boxes of reflection, transmission lines, passive radiator, coupled cavity and horn.
The closed Speaker (Closed Enclosure) is the most simple structure of the speaker system, 1923 Frederick proposed by the speaker unit installed in the constitute a full sealed boxes, which will be the speakers before the sound waves to the radiation and backward radiation sound waves completely isolated, but Due to the existence of the sealed box, the rigidity of the loudspeaker moving mass resonance, so that the lowest resonance frequency of the speaker rose. Feast of the closed Speaker is some deep, but bass analytical, use the speaker of the ordinary hard-fold ring, in order to get satisfactory bass playback, you need a large volume of a large box, use of new types of closed speaker enclosed in the box the elasticity of the compressed air quality, although the speaker is installed in a smaller box, cone behind the cushion will cone to exert anti-driving force, so this small sealed speaker, also known as air cushion speaker.
The bass reflex enclosure (Bass-Reflex Enclosure), also known as phase inversion type speaker (Acoustical Phase Inverter), in 1930 Thuras invention, load one out loud mouth opening in a panel on the box, opening the position and shape, but most of them in the hole also equipped with a sound conduit. Contents of the box plot harmony catheter holes, according to the Helmholtz resonance principle, the resonance at a specific frequency, said anti-resonance frequency. Speaker to the radiation of sound waves down by the catheter, the radiation out loud mouth to the front with the front of the speaker to the radiated acoustic phase stack, it can provide a wider bandwidth than the closed Speaker, has a higher sensitivity, smaller The distortion Ideally, the lower limit than the low frequency playback frequency of the speaker resonance frequency as much as 20%. This speaker with a smaller box will be able to re-release of rich bass, is currently the most widely used type.
Acoustic impedance speakers (Acoustic resistance Enclosure) is essentially an inverted phase-speaker distortion, it aloud port catheter filled with sound-absorbing material or structure, inverting the role of control as a semi-closed chamber so that buffer to Reducing the anti-resonance frequency the broadening bass replay band.
Transmission line speakers (the Labyrinth Enclosure) is named by the classical electrical theory of transmission lines, the speaker behind a wall made of acoustic properties of sound catheter, its length is required to enhance the low-frequency sound wavelength of the fourth or eighth one. In theory attenuation of sound waves by a cone behind, and prevent its reflection to the open end to affect the sound radiation of the subwoofer. In fact, the speaker of the transmission line has mild damping tuning effect, an increase of the speakers near or below the resonance frequency of the acoustic output, and at the same time enhance the bass output to reduce stroke volume. The catheter is usually the sound of this speaker most of the folding was a maze-like, also known as a maze or labyrinth.
The passive radiator speakers (drone Cone, Enclosure) is a branch of the bass reflex enclosure, also known as the empty cone speaker. 1954 Olson and Preston released its opening out loud mouth replaced by a magnetic circuit and voice coil of the empty cone (passive cone), the radiated sound and the front of the speaker cone vibration of the passive acoustic radiation in the same phase working state, the formation of resonance enhanced bass cabinets air and passive cone supporting elements together form the composite sound of cis and passive cone quality. The main advantage of this speaker is to avoid the instability of the sound generated by the reflection aloud Kong, even if the volume can get a good sound radiation effects, so the sensitivity is high, can effectively reduce the magnitude of the speakers are working, standing wave impact, sound clear and transparent.
The coupled-cavity speakers between a sealed and bass reflex cabinet structure, U.S. Henry Lang, published in 1953, its output side of the cone-driven out loud Kong output, the cone on the other side with a closed box coupling. The advantage of this speaker for the low-frequency speakers driven air large increase in low frequency re-coupled cavity tuning system, the cone movement is restricted, out loud output port does not exceed the separate cone of sound output, the exhibition wide put range, so the distortion decreases, to withstand the power increases. 1969, River Island, Japan Lo-D, Yukihiko A, S. W (Acoustic Super Woofer) the speaker is a coupled-cavity type speakers, suitable for small-caliber long-throw speaker distortion replay bass.
Drum sound (Horn type Enclosure) in terms of household type, multi-folded horn (Folded Horn) form, the bell of the horn in the mouth with a larger air load coupling, small diameter drive end, the back of this speaker sealed box cavity pressure to the back of the speaker cone. Maintain a balance, for the protection cone pressure before and after phase inversion horn installed on the speaker front. The folded horn speaker is a derivative of the phase inversion type speaker, the sound is better than a sealed speaker and bass reflex enclosure.