A: The subwoofer's English is Subwoofer. It is literally interpreted as having a "subwoofer" or "under the bass". It can also be said to be a "subwoofer" or a "lower" woofer. In Taiwan, Subwoofer has long been known as the "super" woofer. This is another explanation for "Sub", but it is also reasonable. After the popularity of the family cinema, the subwoofer in the audio industry was quickly smeared as "subwoofer." Honestly, from the literal point of view, it is really not easy to understand the meaning of "overweight"! For audio fans, we still call Subwoofer with a subwoofer!
What is the use of the Q subwoofer?
A: As part of the surround sound system of the home cinema, the subwoofer is responsible for reproducing the Low Frequency Effect in the movie sound. As a two-channel use (also known as a 3D satellite speaker system), the subwoofer is used to make up for the low-frequency, low-frequency, and extremely low-frequency areas of the two-channel speaker.
What kind of Q subwoofer can be divided into?
A: If you distinguish between built-in amplifiers, the subwoofer can be divided into active subwoofers with built-in amplifiers and passive subwoofers without built-in amplifiers. If it is distinguished by the box design, the subwoofer is the same as the general speaker, which can be divided into a sealed system (Sealed System), a bass reflex design (Ported System), a bandpass system (Bandpass System), and a transmission line design ( Transmission Line System) and so on. If it is distinguished by the direction of sounding, there are several kinds of sounds such as sounding toward the front, sounding toward the back, sounding toward the floor, sounding upwards, and making sounds on the left and right sides. If it is distinguished by the single action mode, there are two kinds of single push-pull type, two or three single-phase in-phase sounding type, one single-passive passive radiator composed of in-phase sounding type and the like.
The most advanced subwoofer is built-in amplifier, and also has a built-in bass equalization line, which can moderately attenuate indoor low-frequency standing waves to a certain extent, and achieve low frequency bands below 100Hz or 80Hz. Compare the flat frequency response curve. This subwoofer is ideal and the most expensive.
Q What is a closed subwoofer?
A: The box itself is sealed, there is no hole or gap in contact with the outside, and the woofer can be placed facing forward, rear, side or above. This kind of box is the simplest in manufacturing and easy to meet the quality requirements. Its advantage is that the transient reaction is fast, can withstand large power, and the volume of the box can be made smaller. The closed subwoofer is one of the subwoofers that are commonly seen on the market.
Q What is a bass reflex subwoofer?
A: The box itself has one or more bass reflex holes, so that the woofer back wave in the box can be transmitted out of the box through the bass reflex hole, and mixed with the positive wave of the woofer, thereby increasing the sense of low frequency. . Its advantage is that the distortion is relatively low and the power is relatively large. Compared to a closed cabinet, the lowest cutoff frequency of the bass reflex type can be lower (if the same woofer is used). However, its transient response is not as good as a closed cabinet. The bass reflex subwoofer is also one of the subwoofers that are commonly seen on the market.
Q What is a subwoofer with a general formula?
A: The belt-like box design usually consists of two separate box chambers, one hidden inside and one connected to the outside with a bass reflex hole. The box hidden inside is sealed, the woofer is mounted on the box, and the single diaphragm faces the outside of the box. The woofer is not visible from the appearance of the box. When the woofer moves, the air that drives the outer box passes through the bass reflex hole to form an Acoustic Filter, which produces a fourth-order (24dB attenuation per octave, also designed as a sixth-order) filter for a certain frequency band. . Its advantage is that the power can be the best among all the different types of cabinets, and the transient response is probably only inferior to the closed box. The ultra-low bass with a general formula is relatively rare on the market due to the high cost of manufacturing the cabinet.
Q What is a transmission line subwoofer?
A: Like the transmission line horn, it has a closed pipe with a large and small inside. The large one connects the back of the woofer and receives the back wave of the unit. The small one is the exit. The length of the pipe must be at least one quarter of the wavelength of the lowest cutoff frequency, and the inner wall of the pipe needs to be placed with appropriate sound absorbing material. The function of the pipeline is to use the back wave of the woofer to extend the low frequency cutoff frequency to achieve a lower frequency response. The advantage is that the low frequency can extend downwards even lower. The transmission subwoofer's cabinet manufacturing cost is the crown of all subwoofers, so it is even rarer on the market.
Q What is a passive subwoofer?
A: In the early days, there was no built-in amplifier for driving the speaker unit in the subwoofer. The box only had a passive crossover network responsible for frequency division. This subwoofer is called a passive subwoofer. The so-called "passive" noun is that the subwoofer itself has no kinetic energy and must be driven by an external amplifier. The passive subwoofer music signal is obtained from the speaker output of the latter stage, and itself has a set of signal output terminals for transmitting the music signal that has been split to the two-channel speaker. Since the two-channel speaker and the subwoofer are driven by the same rear stage, the variables of the latter stage are increased, and the driving force is also dispersed. Currently, this subwoofer is quite rare.
Q What is an active subwoofer?
A: After entering the family cinema era, due to the development of the surround multi-channel speaker system, the subwoofer must have a built-in amplifier for the drive unit, so the active subwoofer is immediately flooding the market. Thanks to the built-in amplifier, a low-level music signal (connected to the RCA terminal or XLR terminal) can be obtained from the subwoofer output of the AV surround amplifier. In addition, the general active subwoofer will also have a high-level input and output terminal, which is to use the speaker cable to connect.
In the use of a home theater, the subwoofer cannot be connected by a speaker cable, because the AV signal output is output via the low-level RCA terminal or the XLR terminal, whether it is an AV surround amplifier or an AV processing preamp. Not output from the speaker cable terminal. In the case of a two-channel speaker plus a subwoofer, the user can transmit the music signal to the subwoofer through the second output of the front stage, or connect the subwoofer to the speaker output of the subsequent stage. .
What amplification circuit does the built-in amplifier of the Q subwoofer use?
A: The vast majority of active subwoofers, the built-in amplifiers use Class D amplification lines, and now the more fashionable name is also called the digital amplifier. Why use Class D amplification lines? Because this kind of amplification line is very efficient, does not generate heat, the output power can easily reach hundreds of watts or even kilowatts, and the cost is low. Moreover, the bandwidth of the subwoofer is about 20 Hz-150 Hz, and the distortion of the class D amplifier is high, which is disadvantageous for the disadvantages of the middle band and the high band. Of course, there are also a few higher-level subwoofers that insist on using Class AB amplifiers. If you really work with Class AB amplification, the area of ​​the heat sink on the back of the subwoofer is bound to be quite large, because the output area of ​​hundreds of watts requires as much heat sink area as a hundreds of watts.
Which output terminals are required for the Q subwoofer?
A: In the case of an active subwoofer, the necessary input and output terminals include a low-level output terminal and an input terminal (some also have a Link).
Out, used to connect the second subwoofer), high-level speaker line input and output. Then there must be crossover adjustment, volume adjustment, phase adjustment or phase switching. A few subwoofers also have a high-pass output and a low-pass output. The so-called Qualcomm is to filter out the frequency band below the crossover point and let the frequency band above the crossover point pass. The so-called low pass is to filter out the frequency band above the crossover point and let the frequency band below the crossover point pass.
Q volume adjustment or crossover point adjustment is easy to understand, what is phase adjustment or phase switching?
A: The so-called phase adjustment is continuous or segmental adjustment from 0-270 degrees, and phase switching is only two phase switching of 0 degrees or 180 degrees. Why do you need phase adjustment? Simply put, when the low frequency emitted by the subwoofer is mixed with the low frequency emitted by other speakers, if the phases of the two are the same or close, the total low frequency sense is the sum of the two. Conversely, if the phases of the two are opposite or close to each other, the total low frequency sense will be subtracted. In theory, when the subwoofer is placed on the same horizontal line as the front, middle or two-channel speakers, the low-frequency phase should be the same or close to the front channel or left and right channels. The problem is that for a variety of reasons, the subwoofer cannot be placed on the same horizontal line between the left and right speakers, but at a corner or side, where the sound phase of the subwoofer and other phases The speakers will be different, so it is best to have a phase adjustment.
Generally, the phase adjustment on the subwoofer is divided into two types. The simpler one is the 0 degree and the 180 degree second level switching. The subwoofer is preferably placed between the corner or the front channel or the left and right speakers, even if it cannot be placed. Also try to be as close as possible to the front channel or left and right speakers. Another more precise adjustment is the 0-270 degree stepless or segmented adjustment. This phase adjustment has a higher selectivity and the position of the subwoofer can be more flexible.
How do you determine if the adjusted phase is correct? It's very simple, you just have to listen with your ears, and choose the one with the most low-frequency sense. Of course, you'd better have pink noise or multiple frequency test strips, broadcast the frequency range of 20Hz-150Hz on the test piece, or choose a single frequency (such as 60Hz) to listen, so you can hear the most abundant low-frequency sense. .
QWhen we choose the placement position of the subwoofer, what should we pay attention to?
A: Place the subwoofer as well as the left and right channel speakers, pay attention to the position, because the subwoofer will also be affected by the reflection of the adjacent wall or floor, and the enhancement will occur at certain frequencies (positive phase). The effect will also produce an offset (inverse phase) effect at certain frequencies. In addition, the low-frequency or low-frequency standing waves that are inevitable in the listening space also affect the performance of the subwoofer. So, when you choose the placement of the subwoofer, the first thing to consider is whether I need to increase the volume of the subwoofer by the low frequency enhancement of the corner. The second thing to consider is whether the standing wave (caused by the left and right channel speakers) that originally existed in the listening space will form an enhancement (positive phase) or offset (inverse phase) with the sound wave of the subwoofer. To put it more clearly, when we are placing the subwoofer, we must not only consider the opposite phase of the sound waves between the subwoofer and the left and right channel speakers, but also consider the subwoofer itself and the phase. The opposite phase problem caused by the adjacent floor and wall.
The positive phase and reverse phase problems caused between the subwoofer and the left and right channel speakers can be solved by the phase adjustment device attached to the subwoofer. As for the positive phase and reverse phase problems caused by the subwoofer itself and the wall, how to deal with it? Of course, it can only be handled by the position of the subwoofer. Seeing this, I think readers have come to realize that the seemingly simple subwoofer placement involves such complicated considerations.
Q In the end, how should the subwoofer be placed to solve the problem of positive and negative phase of sound waves formed between it and the adjacent wall?
A: To solve the problem of positive phase and reverse phase of sound waves, the best way is to keep the sound waves reflected by the adjacent wall and the sound waves regenerated by the woofer in the same phase, that is, they are in phase with each other. To be more precise, if you want to keep the four sound waves of the woofer, the floor, the side wall, and the back wall in a positive phase, the safest way is to keep the reflected sound waves and the woofer sound waves within 90 degrees. If the 90 degree phase is converted to a wavelength, it is within a quarter wavelength. However, since the sound wave will be reflected back from the wall and then reflected back, the path of travel is already twice, so we divide the quarter wavelength by two, that is, one eighth of the actual calculation. The wavelength is ok. Welcome to China Home Theater Network!
Perhaps this is a lot of people don't understand, let me give an example: If the subwoofer's selected crossover point is 100Hz, then we take the highest 100Hz wavelength to calculate (other lower frequencies are already covered). The 100 Hz wavelength is 340 meters (sound wave speed per second) divided by 100 Hz, equal to .3.4 meters, and the one-eighth wavelength of 3.4 meters is 42.5 cm. Therefore, we should place the subwoofer at a distance of less than 42.5 cm from the side wall, the back wall, and the floor, so that the sound waves reflected from the back wall, side wall and floor of the subwoofer can It maintains a positive relationship with the main sound wave emitted by the woofer. When all the reflected waves are in positive phase relationship with the main wave, it is the time when the low frequency sense is the most abundant. That's why the subwoofer is placed in the corner to get the most abundant low-frequency feel.
Seeing this, you may think of a problem: Since the subwoofer can be placed in the corner to get the most abundant low-frequency sense, then the left and right channel speakers are not the same in the corner to get the most abundant low-frequency sense? That's right! You can get the most abundant low-frequency sense, but don't forget that the left and right channel speakers are not only the bass, but also the midrange and tweeter. These monomers have a much higher frequency range than the bass. If you calculate according to the above formula, you will find that each monomer requires a different distance. It is easy to generate complex sound waves that mutually enhance or cancel each other, which is harmful. Therefore, in addition to the subwoofer, the general speaker is not suitable for being placed in the corner.
Another advantage of placing the subwoofer in the corner is that the low volume feels so you can turn the volume knob down. When the volume knob is turned low, it means that the amplifier does not have to output such a large amount of power, and the woofer does not have to move so violently, both of which contribute to the reduction of distortion.
Q In addition to the above-mentioned way of selecting the location of the subwoofer, is there any way to help the user find the most appropriate placement?
A: There is another method that is commonly used by ordinary people. It is to play the familiar music software while trying to change the position of the subwoofer. This method is also an effective method, but you must be sure of the music software you play, and determine how the low-frequency effect should behave correctly. In addition, you must also have a correct understanding of the low-frequency performance of the instrument, know how much low-frequency sense, what kind of low-frequency texture is correct. If you have the above capabilities, it is an effective way to repeatedly try the position of the subwoofer by listening.
Can the Q subwoofer be placed in front of the listening position and used as a coffee table?
A: The general situation is not suitable for the front of the listening position, because this position is not easy to get the same phase with the left and right channel speakers. In addition, because it is too close to the listener, the low frequencies emitted by the subwoofer are not easily mixed with the left and right channel speakers. If the subwoofer's crossover point is set low (60Hz), you may not hear the low frequency coming from the subwoofer while listening to some music. In short, this is not a good subwoofer placement.
Can the Q subwoofer be placed behind the listening position?
A: If it is close to the listening position, the same problem will occur when the phase and the low frequency cannot be mixed. It is easy to make people hear that the low frequency band is emitted from the rear subwoofer. If there is a distance from the listening position, then the phase problem must be considered.
Can the Q subwoofer be placed on the side of the listening position?
A: If you try to get close to the side of the left and right channel speakers, the problem is not very big. After the phase adjustment, you can still get the perfect low-frequency mixing feeling. You can't hear the low frequency is sent from the subwoofer alone. If the subwoofer is placed on the side next to the listening position, it is not an ideal position. Unless it is two subwoofers, and the crossover point is low enough, plus proper phase adjustment.
Q Some people say that because the low frequency has no directionality, so the subwoofer can be placed at random?
A: To discuss the problem that the low frequency has no directivity, first of all, it must be determined at what frequency the low frequency has no directivity. After determining the specific frequency, it is also necessary to test whether there is directionality in the outdoor or non-sounding room.
However, it is certain that in the cinema, the 10 Hz extreme low frequency is not directional, because the cinema is using such a low frequency plus super power to create the realistic effect of the earthquake.
Returning to the general listening space, it is assumed that the low frequency below 40 Hz has no directionality, but because the general space is not large enough, it will inevitably produce the third harmonic of the second harmonic of 40 Hz, so the sound wave we hear is not a single 40 Hz. Instead, mix the frequencies of 80Hz, 120H or even 160Hz. At this point we can hear the directionality of the low frequency.
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It can be said that because the listening space of ordinary people is not big enough, the low frequency will be affected by the wall reflection, and the low frequency is really difficult to reproduce, so it is easy to hear the directionality of the low frequency. Therefore, the position of the subwoofer must be tried repeatedly to find the best placement.
Can Q small spaces hear very low frequencies?
A: Many people have vowed to say that they can hear the 20Hz organ sound in the space of Sipingda and Wuping. In fact, this is a "beautiful mistake." According to the law of acoustics, in a confined space, the reproduction of the frequency has an absolute relationship with the distance of the longest side in the space. If the distance is not long enough, the low frequency that can be regenerated is limited. It is defined as: To regenerate a certain frequency, the length of the room must be at least equal to or greater than one-half of the wavelength of the frequency. For example, to regenerate a 20 Hz frequency, the longest distance in the room must be at least half the 20 Hz wavelength (about 17 meters), which is 8.5 meters long.
In this case, why do so many people think that they can hear such a low frequency in their small space? Because they don't hear the true 20Hz, but the 2nd, 3rd, 4th, and 5th harmonics of 20Hz, and these harmonics are misunderstood by 20Hz.
Can the Q subwoofer use two?
A: Yes! When you use two subwoofers, be sure to place them symmetrically. Do not make asymmetric placements. In other words, you can place one left and right symmetrical or symmetrical positions, not one in the right corner, and the other in the center of the rear of the listening position.
Q What is the difference between using a subwoofer and two subwoofers?
A: In addition to the increase in bass energy, one more problem to consider is the acoustic phase problem between each other. If the two subwoofers are placed at the two corners of the same wall, it may be caused by the sound waves canceling each other (in this case, the opposite phase is reversed) to eliminate or reduce the accumulation of sound waves on the left and right walls. Standing wave, this is a positive help for the low frequency frequency response curve. So, when you want to use two subwoofers, it's best to place them in the two corners behind the left and right channel speakers.
Q small space plus subwoofer effect?
A: In a small space, if the low frequency is not enough, adding a subwoofer is still a effective way to solve the problem. However, in the small space, it is easy to generate serious low-frequency standing waves, so you must try repeatedly when selecting the crossover point and adjusting the volume. In addition, the placement of the subwoofer should be tried in an attempt to minimize the negative effects of the mid-low frequency standing wave.
Q In the use of the two-channel speaker plus subwoofer, how do we determine the subwoofer's crossover point selection and volume is correct?
A: I ask you! This problem is the two most critical issues after finding the right position. In my experience, when the crossover point is too high, the mid-low frequency sounds easy to swell, and the real low frequency and extreme low frequency sound like it can't sink. On the other hand, if the crossover point is chosen too low, the full-maintenance of the low-frequency will not be enough, and the low-frequency will appear too soft. Therefore, the correctness of the crossover point will affect the overall concert hall. My suggestion is: with 70Hz as the midpoint, you can set the crossover point to 80Hz, or you can set the crossover point to 60Hz. Focus on the firepower and try these three frequencies repeatedly to find the best two for you. Channel speakers and those who listen to space conditions. Crossovers below 60 Hz or above 80 Hz usually do not have a very good effect.
As for the volume, you must rely on your correct understanding of the instrument. For example, what is the volume of the Jazz Bass playing, and how is the instrument textured? What is the volume when playing Bass? What is the texture of the instrument? How strong is the snoring of the foot drum? How soft? More Q? How heavy? These must be done on your own, so that you can adjust the optimal volume. It can be said that if the snoring of the foot drum is too soft, it is possible that the low frequency is excessive. If the Jazz Bass sound is too soft, it also means that the low frequency is excessive. Because these two instruments are not too soft when listening to the scene.
In addition to the above instruments, the piano can also be used to detect whether the low-frequency sense is moderate. The focus of the observation is on the performance of the bass keys. If the bass keys sound heavy but turbid, the string vibration is not clear enough, and the overall sound is not enough, it means low frequency excess. On the other hand, if the bass key does not have enough weight, the overall piano sounds thin and has no authority, which means that the low frequency is not enough. Only the bass keys sound loud, the sense of scale is large and clear, the overall piano sound is flexible and weighty, that is the correct low-frequency volume.
Perhaps you have to ask: Is the organ suitable for use as a material for testing crossovers and volume? My answer is: If you only want to test the ability of low frequency sinking, the organ's bass level performance can be used as test material. However, since the organ's bass-level performance rarely involves transient reactions and complex scale changes, it is mostly a slow-paced long line, so it is impossible to test the performance of the subwoofer in terms of "dynamics". The conclusion is: As the crossover point and volume adjustment of the test subwoofer, the practicality of organ music is not as good as Bass, foot drum and piano. As for the Western drums or the Japanese drums and the Chinese drums, I don't know the size of the drum used in the recording, and I am not familiar with the energy from the drum when playing, so I don't think it is suitable as a test software. In general, the frequency of Chinese drums or Japanese drums is not too low, but the energy is amazing. Do you know how amazing the energy of the Chinese drum or Japanese drum playing indoors? I have personally experienced it, it will make your eardrum feel a lot of pressure, the body begins to feel uncomfortable, such a huge energy I have not heard on the sound system.
Q What is the meaning of the so-called subwoofer and the low frequency of the left and right channel speakers?
A: The low frequency can't be connected with two meanings. The first meaning is to clearly hear two kinds of low frequencies that cannot be mixed, one from the left and right channel speakers and the other from the subwoofer. The second meaning room hears only a low frequency, but this low frequency does not give the overall sound the best balance. Welcome to China Home Theater Network!
Most of the former problems are caused by poor placement of the subwoofer. If you want to improve, you must find the most suitable position. The latter problem mostly lies in the fact that there is no subwoofer selected. Although how to adjust the crossover point and volume, it does not sound like the low frequency is not enough, the sound is hard and not flexible; that is, the low frequency feels too much, it sounds slim and fat. What's more, I feel that the transient reaction and speed are not right. In this case, if the subwoofer position is still ineffective, then the subwoofer has to be replaced.
Q Most people will consider adding a subwoofer when using a small speaker. I am using a floor-standing speaker. Is it also suitable for adding a subwoofer?
A: Whether it is a bookshelf type small speaker or a floor-standing speaker, as long as you feel that the low-frequency sense is not enough, after trying other methods, you can add a subwoofer to achieve the balance of high, medium and low frequency. Sex. Here I want to emphasize that when listening to music, we do not need excessive low-frequency sense, but need a low-frequency sense that can balance with the high frequency band and the middle frequency band. Therefore, when you install a subwoofer, the volume does not need to be increased too much, so you can achieve the balance of high, medium and low frequency balance. Because of this, when we choose to listen to the subwoofer for music, the first consideration is not how much sound pressure it can emit, but its response is not flexible enough, the control is not good enough, the sound quality is not enough. .
Q There are some subwoofers on the market that are small in size. Is it comparable to a large subwoofer?
A: When designing the subwoofer, it must take into account the structure of the cabinet, the choice of the unit, the design of the crossover, and the expansion of the thrust of the machine. It is necessary to achieve a reasonable balance between these parameters before it can produce a high quality subwoofer. . Some subwoofers have a very small cabinet. This is not a design error. Instead, the cabinet can be used to make up for its shortcomings. For example, a large amount of sound absorbing material is arranged in the box body, and its function is equal to increasing the air volume in the box body, and generally can increase the volume of the box body by up to 40%.
In addition, increasing the power of the amplifier is also a way to compensate for the small size of the cabinet, which is why small cabinet subwoofers often have built-in hundreds of watts of power amplifiers. Finally, some small-volume subwoofers use two woofers for push-pull action. This action can effectively reduce the odd-order harmonic distortion of the individual and increase the sound pressure, which is also an effective way to compensate for the small box.
If the subwoofer is too small due to a design error, the subwoofer's ability to sink down is bound to be limited, and the higher frequency band will expand. In this way, it is not a high quality subwoofer.
Can the effect of a small volume subwoofer be worse than a large subwoofer? The answer to this question is "not necessarily". As mentioned above, the small-volume design and the large-volume design each have their own focus, and it is not possible to determine the advantages and disadvantages of the volume alone. However, it can be affirmed that a large-volume subwoofer can usually obtain a relatively low frequency, while a small-volume subwoofer tends to have a relatively low frequency.
Q Is the subwoofer required to listen to music different from the subwoofer required to watch movie sounds?
A: When listening to music, the performance of the bass instrument is higher, and the subtle volume changes are also highly demanding. Therefore, the subwoofer required for listening to music has higher requirements on the transient response and distortion of the single element. On the contrary, the subwoofer required to watch the movie sound is more focused on the strong impact and volume requirements, so the power requirement for the built-in amplifier is greater, and the robustness of the speaker unit is also higher.
Generally, the subwoofer designed for movie sound has a single diaphragm that is thick and thick, and the single suspension is thick and strong. On the other hand, for the subwoofer designed for listening to music, the single diaphragm tends to be hard and light, and the single suspension is soft and flexible. In my experience, the subwoofer for movie sound can be smaller, but for the subwoofer that you need to listen to music, the size may be larger.
Q How do I choose a subwoofer?
A: First of all, we must first understand the size and needs of our space. If the space is quite large (for example, 10 ping or more), you should use a floor-standing speaker. In this case, you should use a larger subwoofer. Because these speakers are usually designed to listen to music. In addition, the larger subwoofer has a low frequency, and the low frequency characteristics of this type can be compared with the floor-standing speakers.
If the space is not large, you will also use a small bookshelf speaker. At this time, you don't have to choose a large subwoofer. The small volume subwoofer should be more affordable. why? Because the space is small, the real extremely low frequency cannot be regenerated. At this time, the left and right channel speakers do not need a very low extremely low frequency, but need to complement the low frequency between 60Hz and 100Hz. As long as you can make up the low frequency, the scale of the music will become bigger and the overall sound will be solid.
Q When buying a subwoofer, pay attention to the mix of sound quality and speed response?
A: Since most of the subwoofers are responsible for the frequency band between 20Hz and 125Hz, the most frequently occurring frequency band can be reduced to between 40Hz and 80Hz, so the requirements for the matching of sound quality are not demanding. Moreover, in this frequency band, the subwoofer sound you hear cannot judge the sound quality of the sound quality. What's important is that the subwoofer's transient response and speed are fast enough and flexible enough. In other words, the transient response speed must be at least consistent with the left and right channel speakers, so that the combination of the two will succeed.
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