Nowadays,it is unthinkable to have no speakers in computers. The speaker has become an indispensable configuration in the multimedia computer, but with the speaker, if the Mini Speaker is with a poor quality, it just emits some noisy sound all day long, and you will have to bear it and you will not be satisfied! How to choose a speaker that you are satisfied with is a problem that many beginners do not understand. They often think that as long as they can make sound, they will look beautiful. Actually, otherwise, mini speakers are the most difficult to choose among all kinds of computer accessories, and the knowledge of choosing speakers is the biggest! Although many computer newspapers and magazines have introduced how to choose speakers, I still feel that it is necessary to repeat it. After all, choosing speakers is a difficult point. The author starts with the basic knowledge of the speaker, and takes you to recognize it.
& Classification of speakers
In actual life, the speakers used in general computers are all wooden or plastic speakers under 500 yuan. Most of the speakers used are paper cone speakers. Common computer speakers are mainly divided into three types: open, closed and inverted. The first open type speaker has been eliminated, and it is rarely seen on the market; the second type of closed speaker is still common on the market, such as some subwoofers and some small speakers used for surround sound, etc .; for the third Inverted speakers are the mainstream of computer speakers on the market, and seven or eight computer speakers use this structure.
The so-called enclosed speaker, as the name suggests, is that its box is sealed except for the hole of the horn. [Although it is sealed, in fact, there is usually a small part of the speaker. Leakage hole, its role is to equalize the atmospheric pressure inside and outside the speaker]. The advantage of using this kind of speaker is that it can get very good low frequency performance. There are many fibrous sound-absorbing materials on the inner wall of the enclosed speaker. Generally speaking, the more sound-absorbing materials, the better. It is better to fill the box. The advantage of this is that it can be absorbed and weakened. The reflection of the sound wave adjusts the response at the resonance frequency; in addition, the air in the box can be placed in an isothermal compression state, thereby increasing the effective volume of the box. Enclosed speakers are generally used in high-end speakers, and their prices are generally more expensive.
Most computer speakers are inverting speakers, and there are many variations of inverting speakers, such as labyrinth, acoustic resistance, horn and so on. Its characteristic is that there is a phase inversion hole or phase inversion tube on the box plate of the speaker. Why add such an inverting hole or inverter tube? What is it used for? The principle of the inverting sound box is that if the size and position of the inverting tube are properly designed, the sound wave emitted from the back of the original horn basin can be inverted in a certain frequency band through the inverting hole to make it and the sound wave emitted in front of the horn When added together, it becomes in-phase radiation, which reduces the clutter inside the box, increases the low-frequency sound radiation effect, and improves the working efficiency of the speaker. Inverted speakers have the following advantages compared to enclosed speakers. It further extends the lower limit of the low frequency of the speaker, which can generally reach 20Hz, and reduces the nonlinear distortion of the sound wave at the lower limit. At the same time, the use of the inverter tube also reduces the volume in the box, improving efficiency.
& Talk about the crossover
Among the speakers of less than three hundred yuan, many of them do not have a treble or midrange unit [speaker] installed, and no crossover is used. This kind of speaker that does not even have a high midrange unit has the sound quality you do n`t want. It will be better there. Although some speakers of about three hundred yuan are equipped with a treble or high midrange unit, they generally use the extremely simple electronic frequency division method of the volume control board built in the speaker box. Two or three capacitors just don't have a very good crossover effect. As a qualified and excellent speaker, the use of crossover is essential.
So what is a crossover and what does it do? We know that if there are two or more speakers [such as a treble and a bass] in the speaker, they can separately reproduce signals of different frequencies. 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. The frequency division network is simply referred to as a frequency divider. The main function of the frequency divider is to separate the various frequency band components in the audio signal, and let the low-frequency components only for low-frequency units, and the high-frequency components only for high-frequency units. In this way, the low-frequency unit will not consume high-frequency energy in vain, and vice versa.
The second is to protect the high and intermediate frequency speakers. Because the diaphragm is generally high, the diaphragm of the intermediate frequency speaker is small. When low-frequency and large-amplitude signals are added, it is easy to produce overload and distortion, or even damage. It has been said that knowing whether a multi-unit speaker is really equipped with a qualified crossover is the minimum standard for buying a high-quality speaker. If it is even there, there is no talk about stereo! If there is no crossover for some low-end multi-unit speakers, it is best to buy them and add them. The method is very simple. After adding them, the sound quality of your computer speakers will definitely be greatly improved.
& Understanding the speakers
When it comes to speakers, you have to talk about speakers [speakers]. It is the most important part of the speaker. Its performance can determine the quality of the speaker. Its technical indicators can be said to be a large part of the technical indicators of the speaker. If you understand it clearly, then you can basically understand the speaker. Also, when buying speakers, some merchants like to open their mouths and throw away some of the professional terminology of the speakers. You can hear you in the fog and speechless. In fact, strictly speaking, the term should be called a speaker. You read the introduction below, and whoever wants to lie to you with some "strange" speaker terminology in the future will not work.
Speakers can be divided into electric type, electromagnetic type, piezoelectric ceramic type, capacitive type, ion type, etc. according to their working principles, but the most used one is the electric paper cone speaker. If it is divided according to the audio frequency of the speaker, it can be divided into full-band speakers [speakers that can reproduce all audio signals, common are two-basin speakers and coaxial speakers], low-frequency speakers, high-frequency speakers and intermediate frequency speaker. In addition, there are so-called flat panel speakers, folding ring speakers and the like.
What we mainly introduce here is the most widely used electric speakers. The speakers we commonly use in life are basically this kind of speakers. Its basic working principle is to use the mutual driving force between the magnetic field and the current-carrying conductor to drive the vibration of the surrounding air to generate sound waves. It can be mainly understood about its performance indicators, mainly including: nominal power, impedance, frequency response, sensitivity, and distortion, etc. These indicators are also what you must understand when buying speakers.
1. Nominal power
Namely rated power, it is the normal working power of the horn. The horn will not be damaged only if it works for a long time under this condition. And this involves a problem of maximum input peak power [maximum allowable input power], which refers to the maximum power that the speaker can withstand. Due to the different definitions and standards of power in various countries and major audio manufacturers, these values are very different. Everyone should pay attention when purchasing. According to China's regulations, the maximum power of the speaker cannot exceed 1-2 of its nominal power. Times. However, some imported speakers are not necessarily like this. Also, some manufacturers like to mark the peak power as the rated power on the speaker. Don't believe it. The "pronounced" rated power of 300W and 500W, if it can reach 10W, it is great. Also, the nominal power value of the selected speaker should not be less than the output power of the sound card or amplifier.
2. Impedance
The nominal impedance of the horn refers to the impedance value that the horn presents at both ends of its voice coil at a certain operating frequency. The horn can obtain the maximum power when operating on this impedance value. The common impedance values of the speakers are mainly 4, 5, 6, 8, 16 and so on. When purchasing, pay attention to the impedance value of the speaker is not less than the impedance value of the sound card or amplifier, the two should be the same or greater than 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 has the widest adaptability.
3. Frequency response
When a constant voltage is applied to the input end of the horn, the relationship between the sound pressure level at a certain point of the horn axis and the frequency change is called the frequency response. It is an important indicator of the speaker. If divided by speaker, the frequency range of low-frequency speakers is usually between 20Hz-3000Hz; the frequency range of mid-frequency speakers is between 500Hz-5000Hz, and the frequency range of high-frequency speakers is 3000Hz- Between 20000Hz. But it does not mean that the speaker can achieve such a frequency response, the speaker will have such a frequency response index, which has a great light system with the quality of the speaker, the workmanship and materials of the speaker. The frequency range of an excellent speaker today is generally between 60Hz and 20,000Hz. As for some low-end speakers, it is difficult to achieve the above nominal value, so don't believe it when buying.
4. Distortion
Refers to nonlinear distortion. It is divided into three categories: harmonic distortion, intermodulation distortion and transient intermodulation distortion. Among them, harmonic distortion refers to the distortion caused by adding higher harmonic components that are not in the original signal during sound playback. Therefore, harmonic distortion mainly occurs at low frequencies, especially at the resonance frequency. Intermodulation distortion mainly affects the pitch of the sound.
Transient intermodulation distortion refers to the compensation capacitor introduced in the low-frequency amplification or power amplifier stage. When the amplifier inputs the pulse signal, the negative feedback is delayed due to this capacitance, thereby causing the transient overload of the input stage and transient intermodulation distortion Seriously affect the sound reproduction quality. Therefore, it is more important in the speaker and speaker system, and its indicators are closely related to the quality of the speaker. Usually expressed as a percentage, the smaller the value, the lower the distortion. The distortion of ordinary speakers should generally be less than 0.5%, while speakers such as subwoofers should be less than 5%.
5. Dynamic range
What is dynamic range? It refers to the difference in sound pressure level between the strongest sound and the weakest sound emitted by the speaker under the specified undistorted index, and its unit of measurement is dB. The wider the dynamic range, the better, because if your speaker's dynamic range is wider than others 'speakers, then the details of music that cannot be heard on others' speakers can be meticulously expressed on your speakers. When the sound level is almost the same, who has a wide dynamic range of speakers, who has a good sound effect, this is an indisputable law.
6. Pure tone
Pure tone is also one of the important indicators to judge the quality of the speaker. Pure tone refers to adding a positive frequency signal of a certain frequency to the horn within the rated power and rated frequency range. The horn should be free of mechanical noise, ringing noise and garbage sound. Especially for the speakers produced by small factories or small workshops with rough workmanship, it is a common phenomenon to produce impure sound. Everyone should pay attention when purchasing. The quality of the speakers with this quality must be poor. . The reason for the poor pure tone is that the workmanship of the speaker is not good, such as the edge of the paper cone, the bonding of the centering support piece is not strong; the connection of the magnetic plate of the basin frame is not strong; the adhesion of the voice coil and the dust cover is not strong; , Placed incorrectly; there are iron filings or dust in the magnetic gap, etc.
7. Materials for speakers
Finally, let's talk about the materials used for the speakers. The tweeters popular in computer speakers today mainly use titanium membrane domes and soft domes, each with advantages and disadvantages. In addition to the traditional paper cone as the material for the woofer, some also use wool woven cloth, bulletproof cloth, polypropylene PP film, etc. as the material of the speaker. The above materials used as speakers can only be said to have their own advantages. The specific choice depends on your preferences. It is not like the bulletproof cloth used by some newspapers and periodicals. The sound of the speakers using paper cones is better than first-class. The author blows a cold wind here, which can only be said to be a personal blind obedience, unless their ears are really "gold ears". As consumers do not have to blindly follow suit, they can purchase according to their own needs
