Loudspeaker is also known as "horn". Is a very commonly used electro-acoustic transducer device, in the sound of electronic and electrical equipment can be seen in it.
English name: Loudspeakers
Speakers are a kind of electrical signal into an acoustic signal transducer device, the performance of the speaker on the sound quality of the impact is great. Loudspeakers in audio equipment is one of the weakest devices, but for sound effects, it is one of the most important parts. There are many kinds of speakers, and the price varies greatly. Audio electrical energy through electromagnetic, piezoelectric or electrostatic effects, so that its paper cone or diaphragm vibration and with the surrounding air to produce *** vibration (*** sound) and sound.
Low-grade plastic speakers because of its thin box, can not overcome the resonance, no sound quality to speak of (there are some well-designed plastic speakers to be far better than poor-quality wooden speakers); wooden speakers to reduce the box resonance caused by the sound contamination, the sound quality is generally better than plastic speakers.
Often multimedia speakers are dual-unit bifurcated design, a smaller speaker is responsible for the output of the mid-range and high-frequency, while the other larger speaker is responsible for the bass and mid-range output.
Selection of speakers should consider the material of the two speakers: multimedia active speaker tweeter is now dominated by soft dome (in addition to titanium dome for analog audio sources, etc.), it is compatible with the digital audio source to reduce the rigidity of the high-frequency signals to give a person the feeling of tenderness, smoothness, finesse. Multimedia speakers are now better quality silk film and lower cost of PV film and other soft dome of the majority.
Bass unit it determines the characteristics of the sound of the speaker, the choice is relatively important, the most common are the following: paper cone, and there are glue paper basin, paper-based wool basin, tightly pressed basin and so on.
Common speakers
Paper cones sound natural, cheap, better rigidity, lighter material sensitivity, the disadvantage of poor moisture resistance, manufacturing consistency is difficult to control, but the top HiFi systems with paper cones abound, because the sound output is very average, good reproduction.
Anti-bounce cloth, a wider frequency response and lower distortion, is the first choice for those who love strong bass, the disadvantage is the high cost, complex production process, sensitivity is not high light music effect is not very good.
Wool braided pots, soft texture, it is soft music and light music performance is very good, but the bass effect is not good, lack of strength and shock.
PP (polypropylene) cone, it is widely popular in high-end speakers, good consistency and low distortion, all aspects of the performance is noteworthy. In addition there are like fiber diaphragms and composite diaphragms due to the high price is rarely used in popular speakers.
Speaker size is naturally the larger the better, large-diameter woofer can be in the low-frequency part of the better performance, which is in the purchase of the pick. Speakers made with high-performance speakers mean lower transient distortion and better sound quality. Ordinary multimedia speakers woofer speakers are mostly between 3 to 5 inches. Speakers made with high-performance speakers also mean lower transient distortion and better sound quality.
Our most common motorized cone speakers. Motorized conical speakers that we used to call them paper cone speakers, although in 2014 the diaphragm is still mainly paper cone, but at the same time there are a lot of polymer material diaphragm, metal diaphragm, with conical speakers to call it a real name. Tapered cone loudspeakers are largely composed of three major components: the magnetic circuit system (permanent magnets, core columns, magnetic guide plate), vibration system (paper cone, voice coil) and support auxiliary system (centering spars, cone frame, padded edge).
1. voice coil: voice coil is a conical cone speaker drive unit, it is a very fine copper wire wound in two layers on the paper tube, generally around dozens of circles, also known as the coil, placed in the magnetic core column and the magnetic guide plate formed by the magnetic suspect gap. Voice coil and paper cone fixed together, when the sound current signal into the voice coil, voice coil vibration driven by the paper cone vibration.
2. Paper cone: conical cone speaker cone diaphragm used in many types of materials, generally natural fibers and man-made fibers of two categories. Natural fibers are often used cotton, wood, wool, silk, etc., man-made fibers are used rayon, nylon, fiberglass, etc.. As the paper cone is the sound radiation device of the speaker, to a considerable extent determines the speaker's sound performance, so no matter which kind of paper cone, the requirements of both lightweight and good rigidity, can not be deformed due to changes in ambient temperature and humidity.
3. Folded ring: folded ring is to ensure that the axial movement of the paper cone along the speaker, limiting lateral movement and set up, and at the same time play a role in blocking the front and rear of the paper cone air dare circulation. Folding ring material in addition to commonly used paper cone material, but also the use of plastic, natural rubber, etc., after hot-pressing bonded to the paper cone.
4. centering support piece: centering support piece used to support the voice coil and paper cone of the combined parts, to ensure that it is vertical and not skewed. Centering support piece has a number of concentric rings, so that the voice coil in the magnetic gap is free to move up and down without lateral movement, to ensure that the voice coil does not touch with the magnetic guide plate. The dust cover on the centering spine is to prevent external dust from falling into the magnetic gap, avoiding the friction between the dust and the voice coil, and making the speaker produce abnormal sound.
Speaker structure 2
General speaker is composed of: magnet, frame, centering spars, molded ring cone type paper cone. As shown in Figure
Speaker construction
Basic features
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(1) speaker has two terminals (two leads), when a single speaker is used when the two pins are not divided into positive and negative polarity, more than one speaker is used at the same time when the polarity of the two pins are divided.
(2) The speaker has a paper cone, which is usually black in color, but also white.
(3) The shape of the loudspeaker is round, square and oval and other categories.
(4) the back of the speaker cone is a magnet, external magnetic speakers with a metal screwdriver to touch the magnet will feel the presence of magnetic; internal magnetic speakers do not have such a feeling, but there is a magnet inside the shell.
(5) speakers mounted on the machine panel or inside the speaker.
Main types
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There are many types of loudspeakers, according to its principle of energy transfer can be divided into electric (that is, moving coil), electrostatic (that is, capacitive), electromagnetic (that is, reed), piezoelectric (that is, crystalline) and so on, the latter two are used in the rural cable broadcasting network; frequency range can be divided into low-frequency speakers, mid-frequency speakers, high-frequency speakers. These are often used as a combination of speakers in the speaker.
According to the transducer mechanism and structure of moving-coil (electric), capacitive (electrostatic), piezoelectric (crystal or ceramic), electromagnetic (compression spring), electro-ionic and pneumatic loudspeakers, etc., electric loudspeakers have good electro-acoustic performance, solid structure, low cost, etc., are widely used;
Pressing the sound radiation material into paper cone, tube type, diaphragm type; according to the shape of the paper cone Round, oval, double paper cone and rubber folded ring; according to the working frequency of bass, midrange, treble, and some also divided into special tape recorders, special television sets, ordinary and high-fidelity speakers, etc.; according to the voice coil impedance low impedance and high impedance; according to the effect of sub-direct spokes and ambient sound and so on.
Speakers are divided into built-in speakers and external speakers, and external speakers are generally referred to as speakers. Built-in speaker means that the MP4 player has a built-in speaker, so that users can not only through the headphone jack can also be through the built-in speaker to listen to the MP4 player sound. MP4 players with built-in speakers can eliminate the need for external speakers and avoid the inconvenience of having to wear headphones for a long time.
(1) low-frequency speakers
For a variety of different speakers, the quality factor for low-frequency speakers - Q0 value requirements are different. For closed box and inverted box, Q0 value is generally best between 0.3 ~ 0.6. Generally speaking, the larger the caliber, magnet and voice coil diameter of the woofer, the better the low-frequency playback performance, transient characteristics, and the higher the sensitivity. Woofers structural form of cone, also
speakers
there are a small number of flat type. Woofers have a wide range of diaphragm, aluminum alloy diaphragm, aluminum-magnesium alloy diaphragm, ceramic diaphragm, carbon fiber diaphragm, bulletproof cloth diaphragm, glass fiber diaphragm, acrylic diaphragm, paper diaphragm and so on. Aluminum alloy diaphragm, fiberglass diaphragm woofer is generally smaller caliber, bear the power is relatively large, and the use of reinforced paper cone, fiberglass diaphragm woofer replay music tone is more accurate, the overall balance is good.
Q0: the quality factor of the speaker unit is the design and production of speakers must understand a very important parameter. In the impedance characteristic curve of the speaker unit it indicates that the impedance curve at the resonance frequency of the impedance peak of the sharpness of the degree to which it reflects the vibration of the speaker vibration system of the damping state, referred to as the Q0 value, the higher the quality factor of the speaker unit, the resonance frequency is more difficult to control. The low-frequency characteristics of the speaker is usually determined by the quality factor value of the speaker unit and the resonance frequency, where the size of the quality factor and the speaker unit at the resonance frequency of the output sound pressure is related to the low-frequency Q0 value is too low when the output sound pressure of the speaker has not been to the F0 place on the rapid decline, the speaker is in a state of over-damping, resulting in low-frequency attenuation of the excessive Q0 value is too high when the speaker is in the state of under-damping, low-frequency is over-enhanced. The larger the Q0 value, the steeper the peak. Therefore, we say that the quality factor of the loudspeaker can not be too high or too low, usually we take its critical damping value Q0 equal to 0.5-0.7 as the best range of values.
(2) mid-frequency speaker
Generally speaking, the mid-frequency speaker as long as the frequency response curve is flat, the effective frequency response range is greater than the width of the amplification band that it is responsible for in the system, the impedance and the sensitivity and the low-frequency unit can be consistent. Sometimes the power capacity of the midrange is not enough, you can also choose a higher sensitivity, and impedance higher than the bass unit of the midrange, thus reducing the actual input power of the midrange unit. The midrange unit generally have cone and dome two kinds. Only its size and power are larger than the tweeter and suitable for playback in the audio only. The diaphragm of the midrange unit is dominated by soft materials such as paper cones and silk membranes, and occasionally a small amount of alloy dome diaphragms.
(3) tweeter
Tweeter, as its name implies, is a speaker unit for playing back high-frequency sound. Its structural form of the main horn solution type, cone cone type, dome type and aluminum band type and other major categories.
R&D Products
Editorial
Electrostatic Loudspeaker
Over a hundred years ago, on February 14, 1876, Alexander Graham Bell filed one of the most important patents in history, the "telephone". This invention allowed the human voice to travel farther than a shout. Humans also learned about the relationship between sound and electricity, and have been enjoying it ever since.
In order to better play back recorded sound, in 1910, S. G. Brown separated the driver from the diaphragm and invented the 'armature' armature headphone.
Balanced headphones
And in 1910, Baldwin invented the 'balanced armature' balanced armature headphones. The armature is a movable piece of iron (armature) in the middle of a U-shaped magnet, when the current flows through the coil the armature will be magnetized and the magnet to produce repulsion phenomenon, and at the same time drive the diaphragm movement. This design was inexpensive and, although ineffective, was an epoch-making invention at the time, and the technology was mostly used in telephone handsets and small headphones.
In terms of sound-recording technology, Wente and Thuras designed the condenser microphone in 1917.
By the mid-1930s, the electrostatic loudspeaker, based on the principle of the condenser microphone, was introduced.
Loudspeakers
In the early 1950s, the 'constant charge' law was proposed by C. V. Bocciarelli in the U.S.A. P. Walker independently developed the same theory during the same period and applied it to the famous Quad electrostatic loudspeaker design.
The basic principle of electrostatic loudspeaker is Coulomb's law, which is usually a plastic diaphragm plus aluminum and other inductive materials vacuum vaporization process, two diaphragms placed face to face, when one of them is added to a positive current high pressure, the other one will induce a small current, by attracting and repulsing each other to push the air to be able to emit sound. Electrostatic monomer due to the light weight and vibration dispersion is small, so electrostatic speakers work in the middle and high frequency bands, the sound quality is light and detailed, rich in character, it is easy to get clear and transparent middle and high sound. But its efficiency is not high, low sound pressure output, dynamic small, more expensive cost is also its weakness.
Electric
At the same time as Bell, a different type of loudspeaker was proposed. As a hobby, Ernst W. Siemens (founder of Siemens & Halske) patented a prototype electrodynamic loudspeaker on January 20, 1874, which placed a voice coil with a support system in a magnetic field in order to keep the vibrating system in axial motion. At the time, it was used primarily in the relay rather than the loudspeaker field.
On December 14, 1877, Siemens patented the horn, which served as a sound radiator by attaching a parchment to the top of a moving voice coil, which could be made in the shape of an exponential cone; this was the first solid type of horn of the phonograph era.
In 1898, Oliver Lodge patented the first practical motorized loudspeaker, placing the voice coil in motion in a magnetic gap between an inner and outer circular pole plate, and like many inventions, at the time this great invention was too far ahead of its time. This invention determined the structure of 99% of modern moving coil speakers in 2014.
A full 25 years later, in the 1920s, radio broadcasting came along, and C. W. Rice and E. W. Kellogg published the groundbreaking paper 'A New Kind of Non-Horned Unit' detailing the direct radiating loudspeaker, and utilizing the theory to design the $250 Radiola 104 loudspeaker that took the U.S. by storm.
The basic principles of motorized loudspeakers have remained unchanged over the past fifty years, with only improved design details and components. Frequency response range dynamic range and other aspects of the old product has made great progress. Motorized speakers with simple structure, excellent sound quality, low cost, dynamic has become the mainstream of the market in 2014.
Motorized speakers are the most widely used, it is divided into paper cone, horn and dome three. Only the first two are introduced here.
Various speakers
1, paper cone speakers
Paper cone speakers are also known as moving coil speakers.
It consists of three parts: ① vibration system, including conical cone, voice coil and centering support piece, etc.; ② magnetic circuit system, including permanent magnet, magnetic plate and field center column, etc.; ③ auxiliary system, including the cone frame, junction plate, crimp and dust cover. When the voice coil in the magnetic field has audio current through, it produces a magnetic field that varies with the audio current, and this magnetic field interacts with the magnetic field of the permanent magnet, causing the voice coil to vibrate along the axial direction, due to the simple structure of the loudspeaker, full-bodied bass, soft sound quality, wide frequency band, but with lower efficiency.
2, horn-type speaker
The structure of the horn-type speaker, which consists of two parts of the vibration system (tweeter head) and the horn. Vibration system is similar to the paper cone speaker, the difference is that its diaphragm is not a paper cone, but a dome-shaped diaphragm. The vibration of the diaphragm radiates sound waves into the air through the horn (after two reflections). Its high frequency, high volume, commonly used in outdoor and square sound reinforcement.
The horn-type
The horn-type loudspeaker has its origins in the phonograph, and in 1928 Wente and Thuras produced their highly efficient horn-type loudspeaker receivers. The principle of the horn loudspeaker is that the diaphragm pushes the air located at the bottom of the horn and works. Because of the high acoustic resistance, the efficiency is very high, but it is not easy to reproduce the low frequencies because the shape and length of the horn affects the tone. Today, high-efficiency horns are mainly used in professional sound reinforcement.
Ribbon
During the period when the loudspeaker technology described above was taking shape, it became clear that the ideal transducer should use a thin sheet of vibrating membrane that could pass an electric current, and people began to conceive of the ribbon loudspeaker.
In January 1923, Schottky and Gerlach of Siemens Halske patented the first ribbon loudspeaker. It mounted a horizontally wavy pure-aluminum booklet membrane between the poles of a magnet. The wavy pure-aluminum membrane reduced the longitudinal stiffness and lowered the resonant frequency.
In 1931, Olson and Massa produced a ribbon microphone.
The ribbon loudspeaker is mainly used in the mid- to high-frequency range, where it is easy to form a linear source because of its flat frequency response curve and very high upper high-frequency limit, which has very good transient effects.
While the history of human electroacoustics is so convoluted and complex, there are indeed many excellent and innovative electroacoustic loudspeakers emerging today, and in fact many of the best electroacoustic scientists of the last century have been left scratching their heads over these innovative loudspeaker designs.
Car audio
The horn (loudspeaker), generally known as the Horn of Africa, is an indispensable piece of equipment for an audio system. Everything from the "trumpet" people, listen to music and enjoy. Because of the quality of the electrical energy that goes into the "sound energy", the only equipment and the horn, the sound of the entire sound system, the characteristics play a decisive role.
Horn in the car appears more prominent sound system. In order to demonstrate a good tone and direction in the sense that some of the speakers and their layout is very important criteria. Speakers and effects: in the field of car audio, people have been pursuing such effects: in the car like to sit in front of the stage is that all the sound used in the windshield, hair, eyes, like the feeling of being at a concert. The sound of each instrument, you can achieve the best effect of playback. This is often called professional Hi-Fi (High Fidelity High Definition). The key to the ideal Hi-Fi effect is to synchronize the sound source and amplify the signal in the same frequency band. Home audio is not difficult. Since the home stereo frequency and high-mid units in the same fixed frame and all of the music signals are amplified by the same amplifier, the reduction ratio is consistent and relatively easy to achieve a good balance of sound quality. However, due to the limitations of different car audio installation locations, the woofer unit can usually only be installed in the luggage compartment, the bass general unit can only be installed in the front of the car, the tweeter is usually installed near the A-pillar. This effect may just come to listen to the treble and bass from the back to compare with the same month, Alto part is relatively weak. In addition, for different module and power amplification requirements, in a typical car stereo can only take multiple amplifiers to drive the speakers (many designs have a low frequency section that needs to be amplified by multiple amplifiers), so tonal balance is difficult to achieve at a satisfactory level. There are a number of factors involved in meeting these challenges, and the number of speakers and mounting arrangements is one of the keys. Number of speakers
Speaker volume can be determined by assigning the sound pointing to the fine, small roughness more. Advanced than the average number of car speakers speakers in the average vehicle. The installation position of the speakers often car stereo sound effect of the impact of speakers in different installation positions of the same two companies will have a different impact on the installation position of the speakers of the mid-advanced sedan stereo must be subjected to a variety of tests to determine it...
The number of speakers through the correct number of speakers with the right sound pointing fine. Through the number of speakers along with the correct installation experience and skills to cope with different bandwidth speakers installation position, maintain a good direction, compatible with the technology to adjust the power amplifier, and ultimately achieve good results. Installation layout has a direct impact on the Hi-Fi effect from a professional point of view, with an excellent balance of hi-fi sound quality through the front soundstage effect (sound effect feel front), the location of the soundstage (the impact of different sources in the field can be localized with precision), the spatial sense (about the spatial acoustic effect feel the bass response), the playback effect (reproduction of the hi-fi acoustic effect), (voice, tone and image quality) of the audiovisual effect, respectively. results) of the audiovisual effects, respectively. Good hydroacoustic localization (staging) depends to a large extent on the setup of the tweeter in front of the cab and the midrange unit setup around the cab. Because the human auditory system is mainly in the audio part of the sound waves arrive successively in the left and right ear rate sound source location. Nearby a tweeter and speaker installed in front of the door pillar only installed to achieve a coordinated and frequently matched midpoint can form a consistent, coordinated sound source. Taking into account the audience's left and right audio angle also depends on the position of the audio speakers, repeat the calculation to adjust precisely in order to make the car stereo to achieve a good sound field positioning. Therefore, for car stereo effect car speaker layout is very important.
Active directional
In 2014, the second session of the fair, Fudan University scientists said that they have successfully invented a square dance noise "stopping artifacts" - active directional loudspeakers. [1]
Active directional loudspeakers can be used in the car stereo, but they can also be used in the car stereo. [1]
Ordinary loudspeakers emit sound that spreads in all directions, and to achieve orientation, the diameter of the speaker must be made very large. Different from the principle of traditional speakers, active directional speakers first low-frequency sound signals contained in a highly directional high-frequency signals, and then amplified, emitted into the air, and then the air will be the high-frequency signals quickly filtered out, the audible sound signals will be naturally filtered out, and to achieve the directional propagation of the laser-like. [1]
Active directional loudspeakers are able to control sound waves in a specific area, in which they are strong, and out of which they are weak or even absent. If square dancers use this kind of speakers to play music, its nuisance 'embarrassment' can be solved." Ma Jianmin said. In addition to the square dance noise as a "forced stop artifact", active directional loudspeakers can also be used in advertising exhibitions, waiting rooms, bus stops and other scenarios, to achieve the sound of a specific group of people for the directional broadcast. [1]
In 2014, the domestic market has not yet formed the product, the "magic weapon" is expected to be officially unveiled at the end of this year. Optimists believe that if a large number of market, this may be able to solve the plague of square dance noise nuisance problem. [1]
Computer speakers
Win7 system speakers are always automatically deactivated
1, in the "computer" icon on the right button, select "Properties".
2, switch to the "Hardware" tab, select the sound card device in the device manager, right-click to remove the device, find the menu bar operation, scanning changes, the system will pop up the sound card is being installed prompt, wait about 1 minute can be normal;
3, in addition, it may also be caused by the driver deactivation. It is recommended that you go into the device manager to find and right-click on the audio device, choose to uninstall, including removing the driver, and then scan the hardware to allow the system to install the driver on its own. [2]
Performance Comparison
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Phase Judgment
Speaker phase refers to the connection of positive and negative poles of the speakers when they are used in series and parallel: when using more than two speakers, try to ensure the consistency of the direction of the audio currents flowing through the speakers, so that the direction of vibration of the speakers' paper cones can be kept - the same, and the energy of the air vibration is not canceled out. Air vibration energy is canceled out, not to reduce the effect of sound. In order to achieve this requirement requires the series use of a speaker's positive electrode connected to the negative electrode of another speaker connected in turn; parallel use, the positive electrode of each speaker is connected to the positive electrode, the negative electrode is connected to the negative electrode, that is to say, to achieve the requirements of the same phase.
But some speakers in its pins are not labeled positive, negative, which affects the use of series, parallel, for which we have to determine the positive and negative polarity of the speaker. The method is as follows:
1) the multimeter placed in the DC current block of the lowest block, the two pens were connected to the speaker's two pins, and then lightly and quickly pressed the fingers of the speaker's paper cone, and in time to watch the direction of the multimeter's pointer swing, such as the pointer swings to the right, the provisions of the red pen connected to the positive pole, the black pen connected to the negative pole; such as the pointer swings to the left, the provisions of the red pen connected to the negative pole, the black pen connected to the negative pole, the black pen connected to the positive pole, the positive pole, the negative pole, the negative pole, the negative pole, the positive pole, the positive pole, the negative pole, the black pen connected to the negative pole, the negative pole, the negative pole. If the pointer swings to the left, specify that the red pen is connected to the negative pole and the black pen is connected to the positive pole. With the same method and the polarity of the provisions to detect other speakers and well labeled, so that the positive pole, negative series, parallel use can be achieved after the same phase.
2) with a section or two batteries (in series), the positive and negative poles of the battery are connected to the speaker's two pins, in the moment the power supply is connected to pay attention to timely observation of the vibration of the speaker's cone direction, if the cone of paper to the direction of the movement near the magnet, the negative end of the battery at this time is connected to the speaker's positive pins. Alternate battery connected to the speaker's two pins, the paper cone outward movement, the positive pole of the battery is the positive pole of the speaker contact.
Types of speakers and working principle
There are many types of speakers used in 2014. According to their working principle, they can be categorized as electromagnetic, electric, piezoelectric, electrostatic, ionic, airflow converter, airflow modulator and so on. However, the speakers used to play sound in hi-fi systems in 2014 are mainly motorized speakers. So far, the loudspeaker is still the weakest link in the hi-fi sound amplification system. Therefore, to get excellent sound playback effect, how to choose speakers is very important. And want to choose the right speaker, the working principle of the various speakers