I. Classification of speakers
In real life, the speakers commonly used in computers are all wooden or plastic speakers below 500 yuan, and the speakers used are mostly paper basin speakers. Common computer speakers are mainly divided into three categories: open, closed and inverted. The first open speaker has been eliminated and rarely seen in the market; The second kind of closed speakers can still be common in the market, such as some subwoofers and some small speakers used for surround sound. As for the third inverted speaker, it is the mainstream of computer speakers in the market, and seven out of ten computer speakers adopt this structure.
The so-called closed speaker, as its name implies, is that its box body is closed except for a hole for installing the speaker [although it is closed, there is actually a small leak in a certain part of the speaker to balance the air pressure inside and outside the speaker]. The advantage of using this loudspeaker is that it can obtain good low frequency performance. Generally, the inner wall of a closed speaker will be attached with a lot of fibrous sound-absorbing materials. Generally speaking, the more sound absorbing materials, the better. It's best to fill the box. The advantage of this is that it can absorb and weaken the reflection of sound waves and adjust the response at resonance frequency. In addition, it can also make the air in the box in an isothermal compression state, thus increasing the effective volume of the box. Closed speakers are generally used in high-end products of speakers, and their prices are generally more expensive.
Most computer speakers are inverted speakers, and there are many variants of inverted speakers, such as labyrinth, acoustic resistance, horn and so on. It is characterized in that there is an inverter hole or inverter tube on the box board of the sound box. Why do you need to add such an inverter hole or inverter tube? What is the use of it? The principle of the inverter speaker is that if the size and position of the inverter tube are reasonably designed, the sound wave emitted from the back of the original speaker can be inverted in a certain frequency band through the inverter hole, so that it can be superimposed with the sound wave emitted from the front of the speaker and become in-phase radiation, thus reducing the clutter in the box, increasing the low-frequency sound radiation effect and improving the working efficiency of the speaker. Compared with the closed speaker, the inverted speaker has the following advantages: it further expands the lower frequency limit of the speaker, which can generally reach 20Hz, and reduces the nonlinear distortion of sound waves at its lower limit. At the same time, due to the use of inverter tubes? The volume in the box is reduced and the efficiency is improved.
2. Talk about the frequency divider
Many speakers below 300 yuan are not equipped with treble or midrange units, so there is no need for frequency divider. The sound quality of this speaker without a midrange unit will not be as good as you think. Although some speakers around 300 yuan are equipped with treble or treble units, they usually adopt an extremely simple electronic frequency division method on the built-in volume control panel of the speakers, and only two or three capacitors are welded on it at most, which cannot achieve a good frequency division effect at all. As a qualified excellent speaker, the adoption of frequency divider is essential.
So what is a frequency divider and what does it do? We know that if there are two or more speakers [such as a treble and a bass] in the sound box, signals with different frequencies can be played back separately. Because the input audio signal is full-band, it is necessary to add a frequency division network to distribute the entire audio signal to each unit. Frequency division network is called frequency divider for short. The main function of the frequency divider is to separate each frequency band component in the audio signal, so that the low frequency component is only available to the low frequency unit and the high frequency component is only available to the high frequency unit. In this way, low-frequency units will not waste high-frequency energy, and vice versa.
Second, it can protect high and intermediate frequency speakers, because the diaphragm of high and intermediate frequency speakers is generally small, and with low frequency and large amplitude signals, it is easy to overload, distort or even damage. It has been said that knowing whether a multi-unit speaker is really equipped with a qualified frequency divider is the minimum standard for selecting a high-quality speaker. If there is no such thing, what about the stereo! If some low-end multi-unit speakers don't have a frequency divider, it's best to buy them and add them. The method is very simple. The sound quality of your computer speaker will definitely be greatly improved.
Step 3: Understand the horn
When it comes to speakers, you can't help but talk about speakers. It is the most important component in the speaker, its performance can determine the quality of the speaker, and its technical indicators can be said to represent the technical indicators of the speaker to a large extent. Understand clearly, then you can say that you have a basic understanding of the speaker. Also, when buying speakers, some merchants like to throw you some technical terms of speakers with their mouths open and their mouths closed, which makes you confused and speechless. In fact, strictly speaking, it should still be called the term of the speaker. After reading the following introduction, anyone who wants to cheat you with some "strange" speaker's technical terms in the future can't do it.
According to its working principle, speakers can be divided into electric, electromagnetic, piezoelectric ceramics, capacitors, ions, etc., but the most widely used is the electric paper cone speaker. If speakers are divided according to audio frequency, they can be divided into full-band speakers [speakers that can play back all audio signals, such as double-basin speakers and coaxial speakers], low-frequency speakers, high-frequency speakers and intermediate-frequency speakers. In addition, there are so-called flat panel speakers, folding ring speakers and the like.
This paper mainly introduces the most widely used electric speakers, which are basically common speakers in our lives. Its basic working principle is to use the mutual driving force between magnetic field and current-carrying conductor to drive the surrounding air to vibrate and generate sound waves. We can mainly understand its performance indicators, including: nominal power, impedance, frequency response, sensitivity, distortion and so on. These indicators are also what everyone needs to know when purchasing speakers.
1. Nominal power
That is, the rated power, which is the normal working power of the horn. Under this condition, the horn will not be damaged if it works for a long time. This involves a maximum input peak power ratio [maximum allowable input power], which refers to the maximum power that the speaker can bear. Due to the different definitions and standards of power in different countries and major audio manufacturers, these values vary greatly. When purchasing, it should be noted that according to the regulations of our country, the maximum power of the speaker cannot exceed 1-2 times of its nominal power. However, some imported speakers are not necessarily like this. In addition, some manufacturers like to mark the peak power as the rated power on the speaker. Don't take it for granted Its "so-called" rated power values of 300W and 500W will be great if it can reach10 W. In addition, the nominal power value of the selected speaker cannot be seriously less than the output power of the sound card or power amplifier.
2. Impedance
The nominal impedance of a horn refers to the impedance presented at both ends of its voice coil at a certain operating frequency, and the maximum power can be obtained when the horn runs at this impedance. Common impedance values of speakers are 4, 5, 6, 8, 16 ohm, etc. It should be noted that the impedance value of the speaker should not be less than that of the sound card or power amplifier, and both should be equal to or greater than that of the sound card. If you don't know the output impedance value of the sound card, you can also choose a speaker with an impedance of 8 ohms, which is the most widely used.
3. Recording and playback amplitude-frequency response
When a constant voltage is applied to the input end of the horn, the relationship between sound pressure level and frequency at a certain point on the axis of the horn is called frequency response. It is an important indicator of speakers. If speakers are divided, the frequency range of low-frequency speakers is usually between 20 Hz and 3000 Hz. The frequency range of intermediate frequency horn is between 500 Hz and 5000 Hz, and the frequency range of high frequency horn is between 3000 Hz and 20000 Hz. But it doesn't mean that the loudspeaker can achieve such a frequency response, and the loudspeaker will have such a frequency response index, which has a great optical system with the quality of the loudspeaker, the workmanship of the loudspeaker and the materials used. Today, the frequency response range of an excellent speaker can generally reach 60 Hz-20,000 Hz. As for some low-end speakers, it is difficult to reach the above nominal value, so don't be credulous when buying.
Step 4 deform
Refers to nonlinear distortion. It can be divided into harmonic distortion, intermodulation distortion and transient intermodulation distortion. Among them, harmonic distortion refers to the distortion caused by adding higher harmonic components that the original signal does not have in sound playback, so harmonic distortion mainly occurs at low frequencies, especially at the vibration frequency of * * *. Intermodulation distortion mainly affects the tone of sound.
Transient intermodulation distortion refers to the introduction of compensation capacitor in low-frequency amplifier or power amplifier stage, which delays the negative feedback when the amplifier inputs pulse signals, makes the input stage instantly overloaded, produces transient intermodulation distortion, and seriously affects the quality of sound reproduction. Therefore, it is more important in loudspeakers and loudspeaker systems, and its index is closely related to the quality of loudspeakers. Often expressed as a percentage, the smaller the value, the smaller the distortion. The distortion of ordinary speakers should generally be less than 0.5%, and speakers such as subwoofers should be less than 5%.
5. Dynamic range
What is dynamic range? Refers to the sound pressure level difference between the strongest sound and the weakest sound emitted by the speaker under the condition of specified undistorted index, and its measurement unit is dB. The wider the dynamic range, the better, because if the dynamic range of your speaker is wider than that of others' speakers, then the details of music that you can't hear on others' speakers can be displayed in detail on your speaker. In the case of similar sound levels, it is an indisputable law that whoever has a large dynamic range of speakers will have good sound effects.
6. pure tone
Pure tone is also one of the important indicators to judge the quality of speakers. Pure tone refers to adding a positive signal with a certain frequency to the horn within the rated power and frequency range, and the horn should be free of mechanical noise, collision sound and garbage sound. Especially the speakers produced by small factories or workshops with rough workmanship, impure timbre is a common phenomenon. Pay attention when buying. The quality of speakers of this quality is definitely not good. The reason why the pure tone is not good is that the speaker works poorly, such as the blank holder of the paper basin, and the adhesion of the centering piece is not strong; The magnetic conduction plate of the basin frame is not firmly connected; Voice coil and dust cover are not firmly bonded; Voice coil is deformed and improperly placed; There are iron filings or dust in the magnetic gap.
7. Speaker materials
Finally, let's talk about the speaker's materials. Nowadays, the popular tweeter unit of computer speakers mainly adopts titanium dome and soft dome, each of which has its own advantages and disadvantages. In addition to the traditional paper basin, some woofers also use wool woven cloth, bullet-proof cloth, polypropylene PP film and so on as the material of the speaker. The materials used for the above speakers can only be said to have their own advantages, and the specific choice depends on your preferences. It's not bulletproof cloth touted by some newspapers. The speaker of wool woven basin is definitely superior to the speaker of paper basin in timbre. The author blows a cold wind here, which can only be said to be blind obedience, unless their ears are really "golden ears." As a consumer, you don't have to blindly follow the trend, you can choose according to your own needs.
Four. others
Above, we understand the classification of speakers, sound boxes and frequency dividers. Next, let's look at the box of the speaker. There are two common computer speakers on the market: plastic and wood. Plastics are mainly used for low-grade speakers with low requirements for listening effect, or win at low prices; Or get your "heart" with an ever-changing appearance. It is also a good choice to buy a cheap and beautiful plastic speaker for people who are not demanding.
But for wooden speakers, everyone should be careful. Since we chose the wooden speaker, we took a fancy to its excellent quality. At present, low-priced wooden speakers are mostly medium density boards, while high-priced ones are real pure boards. "You get what you pay for." Everyone should pay attention to the distinction when shopping. There are also some fake wooden speakers produced by "Y" factory, most of which are made of plywood or even cardboard. How to distinguish them? In addition to carefully looking at the differences in appearance, you can also use something useful, such as nails to gently cut off the exposed layer of the speaker. It is easy to distinguish the "prototype" of solid wood and plywood. Secondly, you can knock on the box by hand and listen to the sound it makes, and the difference in materials will be exposed. Finally, you can pick up the speaker and look at the bottom. This is the easiest place to "show your true colors" and the most easily overlooked detail by counterfeiters. The truth is clear at a glance. The last thing to do is to weigh the speaker. The heavier, the more real. This is the key.
Finally, talk about the power supply problem of the speaker. At present, most computer speakers are active speakers, and the quality of their built-in power supply is directly related to the quality of the speakers. The advantage of excellent audio equipment is that it is superior to power supply. Some audio manufacturers in Europe and America even think that the power supply cost of a good equipment accounts for about half of the whole equipment, which shows its importance. If the quality of the power transformer inside is too poor, if the inferior iron core transformer is used, the quality of the speaker will be seriously affected. The author believes that a good active speaker requires its power transformer to have sufficient power reserve and high response speed from transformer to filter circuit, so as to ensure sufficient energy for the power amplifier circuit and speaker to respond quickly.
Generally speaking, a high-grade speaker mostly adopts high-quality iron core transformer or "ring transformer" whose quality far exceeds that of iron core transformer. Buying a speaker can properly understand these situations.
How to Choose a Computer Speaker (2)
Five. Four-step selection of speakers
1. Consider
This is the first step in buying speakers. You can weigh the speaker with your hand. Generally speaking, the heavier the speakers of the same grade, the better the quality. This method can be widely used in the procurement of other audio products. The heavier the weight, the more authentic the speaker materials are, and there is no cutting corners. Imagine, from the wood used for speakers to speakers, amplifiers and power supplies, which one will achieve superior quality without adding two pounds? Do you think it is possible to produce beautiful music with that kind of speaker that feels light and "less than two pounds"?
Look at the appearance
This is also an important step. First, you can see whether you are satisfied with the overall shape of the box, and then carefully look at the outer layer of the speaker, whether there are obvious bubbles, scratches and roughness in the layer; Secondly, carefully check whether the combination between the lower box plates is tight and tidy. In addition, you can take off the dust-proof veil on the front panel and carefully check whether the material, material and specifications of the tweeter are consistent with the instructions. In addition, you can focus on checking whether the tweeter, inverter tube and box are firmly and tightly fixed. Finally, we can see if the fastening screw on the speaker is a hexagon screw, which is a detail. Most low-grade or fake products use ordinary self-tapping screws.
3. Understand the performance indicators
First of all, choose the well-known speakers in the market. We can't say miscellaneous brands here, because all the performance indicators given in its manual are definitely false and not credible at all. Although we can't believe all the performance index data given in the manual of a brand speaker, we can't believe some things completely. It is still necessary for reference when purchasing. Besides knowing whether the weight, appearance size and accessories of the speaker are roughly equivalent to the nominal ones, you can also know the nominal power, impedance, frequency response, distortion, dynamic range and so on. The authenticity and exaggeration of the speaker, and whether its speaker is an anti-magnetic speaker, etc.
4. Listening is believing
When choosing speakers, you can also choose several brand speakers of different brands or grades to audition. Because the places where speakers are usually sold are very noisy, everyone should pay attention. Of course, it is best to go to a speaker store or an agent store with an audition room, which can generally provide you with more comprehensive services, and the quality of its speakers is generally more authentic than that of some grocery stores. In most places where there is no such environmental condition, you can bring your usual music CDs to listen to, and you can generally know which speaker has better expressive force. Of course, if you really can't count, you can also go directly to the agency to choose the famous products with good reputation and trust in the market.
The above is mainly used for people who have certain requirements for speakers. For those people and places that don't have high requirements for speakers, such as game halls and internet cafes, it is enough to choose a cheap small plastic speaker, but some experiences in this paper are also helpful for you to choose low-grade speakers. After all, there will be a positive "Y" difference in low-end speakers! We also spend 30 yuan to sell a small plastic speaker, some of which can play well, others will be miserable, and they will give you "squeaking" all day, which will make you upset.
Overview of intransitive verbs market
At present, the most popular private computer speakers in the computer market are mostly brand speakers in 300 yuan or around 300 yuan, and the speakers with higher prices are only used by a few computer enthusiasts or music enthusiasts. This article will not be introduced here. As long as you buy it properly, there are many good things in the speakers around 300 yuan or even lower.
1. Light cavalry series
In Runbao's light cavalry series, M 1, M2, M3, etc. are common low-priced positions in the market now. M2 adopts TDA7269, the power amplifier block of SGS company, and M3 adopts TDA2030, with good quality. The market price of M2 is about 180 yuan, while the market price of M3 is only about 240-260 yuan. The power of M3 is 2X9.5W, the frequency response range is 70Hz-20KHz, and the impedance is 8Ω. The high-pitched unit adopts soft dome, and the low-pitched unit adopts wool paper basin. The whole speaker weighs about 5Kg.
2. rambler series
The common low-priced speakers in the rambler market mainly include 800TC and 1000TC and so on. They are all anti-magnetic designs, and the prices are all within 200 yuan, which is more suitable for ordinary consumers to buy. For example, the frequency response of 800TC is 85Hz- 16KHz, the power is 2X7W, and the impedance is 8ω. The bass unit is a 4.5-inch full-range speaker with foam edges, and the treble unit is made of PP synthetic material.
3. Shock wave series
Shock wave series mainly include WAV500Q, WAV 1000A, etc. Its price is not expensive. For example, WAV 1000, power 2X 15W, frequency response 45HZ-20KHZ, and impedance 8ω. Its high-pitched unit adopts 1 inch PV membrane dome, and its low-pitched unit adopts 4-inch corrugated basin.
The above is just a brief introduction to three popular low-cost and high-performance computer speakers on the market. In fact, in addition to the speakers at this price, there are many computer speakers with good cost performance and many speaker brands such as Sannuo, Guomin, Supersonic, Fenda, Innovation, Iron, etc., all around 200-700 yuan, which are suitable for mass consumers to buy. Finally, I wish everyone can buy a good speaker with satisfaction.