First, the impact of indoor acoustic environment In the multi-channel sound system, currently the most representative of Dolby Pro Logic four channels, it is still the most popular multi-channel sound system. Because the surround track uses two surrounds The channel uses two surround speakers, so the system requires five speakers. Since the advent of the Dolby AC-3 digital multichannel system, the discrete 5.1 channel has quickly become the new multi-channel standard for home theater.
The indoor acoustic environment has a certain influence on the indoor sound field created by the multi-channel speaker. Different room sounds have different spatial acoustic characteristics. The multi-channel sound system uses multiple speakers to represent the sound image and create a surround sound effect. This is not an easy task. If there is no ideal indoor acoustic environment to match, then the comprehensive sound effect will not be good. According to the theory of acoustic psychology, the early reflection sound of less than 1ms in the interior is delayed. Significant interference with direct sound will make the sound become more turbid, which will affect the sound image localization. The early reflection sound between 1~30ms will have less interference to the direct sound, and it will be combined with the direct sound. It helps to increase the loudness, but it may change the tone of the direct sound. As for the reflected sound after 30ms, the human ear usually thinks it is a reverberation sound. For the above reasons, we must do a good job of sound absorption and diffusion in the audio-visual room. Acoustic processing such as sound insulation, otherwise, excessive reverberation will reduce the clarity and consistency of the sound and affect the playback sound.
In order to illuminate the grand stereo field of the theater, the room for audio-visual use should not be too small. If possible, sound-absorbing materials should be added.
Second, the speaker is placed on the premise of a good indoor acoustic environment, the more accurate the sound image is positioned, the more realistic the sound is, the more it can show the vivid effect of the sound and image. First look at the placement of the speakers in the theater. The picture below shows the speaker layout for each channel of the actual theater with surround sound.
The left and right channel front speakers are separated from each other by almost the same distance as the movie screen. The front speakers are usually discharged behind the movie screen, and they can pass the sound to the audience through the small gap of the screen. Therefore, this speaker can be placed at half the height of the screen.
The subwoofer is not necessarily placed in a symmetrical position in the front speaker cluster;
The standard theater has a lot of surround speakers, which together with the front speakers really "surround" the audience.
After referring to the above examples of speaker placement , let's go back and see how the speakers should be placed for the best sound. Here, we have to pay attention to the problem that the indoor play space we encounter may be much smaller than the real theater. Below, we will discuss the placement of three front (left, center, and right) speakers, then surround the sound box, and finally study the placement of the subwoofer.
1. The center speaker of the center channel speaker is placed as close as possible to the center of the image screen. The center channel speaker has the greatest influence on the sound quality of the movie dialogue, in order to ensure that the dialogue is accurately positioned in the center of the screen and the sound Clearly, you should use a separate speaker designed specifically for the center channel, instead of using an ordinary bookshelf speaker or a speaker inside the TV.
Most of the center channel speakers use a horizontal horizontal box, the best place for the top of the TV (if the front projection display screen is placed behind the screen), it should be as close as possible to the screen. If it is limited by the space of the room A more economical placement scheme can be used, that is, no center speaker is provided. However, the working mode of the AV amplifier should be placed in the "phantom" channel mode, so that the information of the center channel is from the left and right speakers. Balanced release, its sound is just in the center of the screen, which is suitable for small listening rooms. Of course, it is best to set up a center speaker.
2. The placement of the left and right channel main speakers has a certain relationship with the position of the center channel speakers. In order to ensure the smoothness of the left and right movement of the sound image, they should be placed on both sides of the center channel speaker, and the three speakers should be at the same distance from the position of the best listener in front of the screen. In general, the center speaker should be placed a little longer than the left and right speakers until the sound field can be completely combined to create a truly unified sound image. The distance of the back is related to the size of the space, the listening position and the speakers used, which can be determined by experiment. In addition, the vertical height of the left and right channel speakers is preferably not higher or lower than the center speaker's axis by 0.3m (preferably slightly lower), otherwise the left, middle and right three The height difference of the speakers is too large, and the front sound image gives a sound jump when it is laterally displaced. Generally, floor-standing speakers can meet the above requirements. If you use a bookshelf speaker for the left and right speakers, you should fix them on the speaker stand so that it meets the above requirements.
The distance between the left and right channel speakers leaving the screen is related to the size of the screen. If you use a large, medium-sized screen color TV in a small room, the left and right channel speakers can be placed close to the sides of the screen. If the screen is small, you can make them a little further away from the screen to get a wider stereo field. But don't go too far from the screen, so as not to give people a false feeling because the sound image position is too far from the picture. From this point of view, there is a shortage of "innate" - the environment is too small. In summary, the sound directivity of the left, middle and right three-channel speakers is heavier than the diffusivity, that is, the radiation angle range of the three channels should be oriented toward the optimal listening position. This reduces the effects of reflected sound from the floor, walls and roof, and properly ensures the clarity of the sound image.
3. Place the surround channel speakers
Surround speakers are used to create an atmosphere that also plays an important role in the entire speaker system.
A. Types of Surround Speakers Currently, there are two types of surround speakers, one is a common unipolar small speaker, which is usually placed on the speaker stand or hung on the wall. Another type of surround speaker is THX recommended dipole speakers, each with two back-to-back speakers installed, all connected in reverse phase. This kind of speaker only emits high-frequency sound to the front and rear and can not produce low-frequency sound (even Entering the low frequency signal and also not paying the bass due to the offset.) Why is this? Let's look at the working process of the dipole speaker. Two speakers are placed back to back in the speaker, and the two speakers are fed. In the opposite phase of the signal, the A speaker inputs a positive polarity signal, and the paper cassette moves forward, compressing the front air (increased density). At the same time, the B speaker inputs a negative polarity signal, and the low box moves backward, so that The air in front of it is sparse (reduced density), so the direction of the sound wave in front of the two speakers is opposite. If the two speakers feed in the full-band signal, the low-frequency is strong because of its long wavelength, so the low-frequency sound from the A speaker will Winding around The B-speaker is weakened (cancelled); while the medium-high frequency signal has a short diffractive power due to its short wavelength, the mid-high frequency sound on both sides of the speaker is small, so the offset effect in front of the speaker is not obvious, so two The speaker only emits low-frequency sounds in the middle and high-frequency sounds of the front and rear. The purpose of using the dipole-type speakers is to avoid excessive directionality.
For the audio industry, the dipole speaker is a very strange type. This kind of speaker needs to be developed to mature. This kind of speaker is not full frequency band, because the frequency below 100MHz has been cut off. Therefore, the speaker is used because it only sounds forward and backward at the same time and never sounds to the side where the listener is located, and the sound is heard before the listener is filled with the listening room, so that a hearing habit can be created. Surrounding sound.
B. The arrangement of the surround speakers of the surround speakers should be different depending on the listening environment (room conditions) and the type of loop speakers. The speakers of the left and right surround channels should be more diffuse than the sound. Directionality, which is conducive to create a rich surrounding atmosphere. When placing dipole-type speakers , two factors should be considered: resonance and self-fading. The best anti-resonance is 20% indoor space from the ceiling (or ground). At the height (if the indoor height is 2.5m, the best position is 50cm above and below). In order to make the frequency response smoother, a new device called low frequency "trap" (absorbing low audio) can be added to eliminate the reflection that causes the sound to decay.
For direct-radiation loop speakers, there are many options to consider. For example: fixed on the walls on both sides and pointing them to the rear corner; fixed on the rear wall, making them open and upward in an inverted figure-eight shape and Towards the junction of the side wall and the ceiling; placed on the floor against the wall on both sides, pointing upwards to the junction of the wall and the ceiling, etc. Many other options can be designed according to the specific conditions of the room. The surround sound field of the home theater is mainly indoors. Each anti-sound is formed by the acoustic reflection and refraction of the surrounding speakers, and the room acoustic conditions of different rooms vary widely. As long as the patience test and careful comparison, the best placement plan will be found.
4. The subwoofer is usually placed near the corner of the front wall, preferably more than 1m from the corner, which can reduce the interference of standing waves. You can also put the subwoofer on both sides of the best listening position. Keep the proper distance, because the human ear is not sensitive to the directionality of the subwoofers from both sides, so the subwoofer will not interfere with the original sound image localization of the front three channels. Of course, the best pendulum The placement position should still be determined by experimentation.
The method described below may be helpful in finding the best placement of the subwoofer. Place the subwoofer in the best listening position (temporarily remove the nearby debris), connect its speaker cable and play a strong bass repeatedly. The effect of the music, then carefully around the room to listen. Listen, ask the ear to stick to the ground, roughly at the height of the subwoofer. When listening, find the most stable, deepest, clearest point of the bass, that is super The best placement of the subwoofer.
With the advent of the information age, the rapid development of computer multimedia technology, the universal application of network technology, the establishment of command and control centers, network management centers, small to temporary meetings, technical lectures, are eager to get a big picture. Multi-color, high brightness. High-resolution display, while traditional CRT displays are difficult to meet people's requirements. The rapid development of large-screen projector technology in recent years has become an effective way to solve large-color display of color, and the scope of application has been further expanded, and the market has become increasingly active due to the growth of demand. We will now introduce how to choose a projector.
First, the impact of indoor acoustic environment In the multi-channel sound system, currently the most representative of Dolby Pro Logic four channels, it is still the most popular multi-channel sound system. Because the surround track uses two surrounds The channel uses two surround speakers, so the system requires five speakers. Since the advent of the Dolby AC-3 digital multichannel system, the discrete 5.1 channel has quickly become the new multi-channel standard for home theater.
The indoor acoustic environment has a certain influence on the indoor sound field created by the multi-channel speaker. Different room sounds have different spatial acoustic characteristics. The multi-channel sound system uses multiple speakers to represent the sound image and create a surround sound effect. This is not an easy task. If there is no ideal indoor acoustic environment to match, then the comprehensive sound effect will not be good. According to the theory of acoustic psychology, the early reflection sound of less than 1ms in the interior is delayed. Significant interference with direct sound will make the sound become more turbid, which will affect the sound image localization. The early reflection sound between 1~30ms will have less interference to the direct sound, and it will be combined with the direct sound. It helps to increase the loudness, but it may change the tone of the direct sound. As for the reflected sound after 30ms, the human ear usually thinks it is a reverberation sound. For the above reasons, we must do a good job of sound absorption and diffusion in the audio-visual room. Acoustic processing such as sound insulation, otherwise, excessive reverberation will reduce the clarity and consistency of the sound and affect the playback sound.
In order to illuminate the grand stereo field of the theater, the room for audio-visual use should not be too small. If possible, sound-absorbing materials should be added.
Second, the speaker is placed on the premise of a good indoor acoustic environment, the more accurate the sound image is positioned, the more realistic the sound is, the more it can show the vivid effect of the sound and image. First look at the placement of the speakers in the theater. The picture below shows the speaker layout for each channel of the actual theater with surround sound.
The left and right channel front speakers are separated from each other by almost the same distance as the movie screen. The front speakers are usually discharged behind the movie screen, and they can pass the sound to the audience through the small gap of the screen. Therefore, this speaker can be placed at half the height of the screen.
The subwoofer is not necessarily placed in a symmetrical position in the front speaker cluster;
The standard theater has a lot of surround speakers, which together with the front speakers really "surround" the audience.
After referring to the above examples of speaker placement , let's go back and see how the speakers should be placed for the best sound. Here, we have to pay attention to the problem that the indoor play space we encounter may be much smaller than the real theater. Below, we will discuss the placement of three front (left, center, and right) speakers, then surround the sound box, and finally study the placement of the subwoofer.
1. The center speaker of the center channel speaker is placed as close as possible to the center of the image screen. The center channel speaker has the greatest influence on the sound quality of the movie dialogue, in order to ensure that the dialogue is accurately positioned in the center of the screen and the sound Clearly, you should use a separate speaker designed specifically for the center channel, instead of using an ordinary bookshelf speaker or a speaker inside the TV.
Most of the center channel speakers use a horizontal horizontal box, the best place for the top of the TV (if the front projection display screen is placed behind the screen), it should be as close as possible to the screen. If it is limited by the space of the room A more economical placement scheme can be used, that is, no center speaker is provided. However, the working mode of the AV amplifier should be placed in the "phantom" channel mode, so that the information of the center channel is from the left and right speakers. Balanced release, its sound is just in the center of the screen, which is suitable for small listening rooms. Of course, it is best to set up a center speaker.
2. The placement of the left and right channel main speakers has a certain relationship with the position of the center channel speakers. In order to ensure the smoothness of the left and right movement of the sound image, they should be placed on both sides of the center channel speaker, and the three speakers should be at the same distance from the position of the best listener in front of the screen. In general, the center speaker should be placed a little longer than the left and right speakers until the sound field can be completely combined to create a truly unified sound image. The distance of the back is related to the size of the space, the listening position and the speakers used, which can be determined by experiment. In addition, the vertical height of the left and right channel speakers is preferably not higher or lower than the center speaker's axis by 0.3m (preferably slightly lower), otherwise the left, middle and right three The height difference of the speakers is too large, and the front sound image gives a sound jump when it is laterally displaced. Generally, floor-standing speakers can meet the above requirements. If you use a bookshelf speaker for the left and right speakers, you should fix them on the speaker stand so that it meets the above requirements.
The distance between the left and right channel speakers leaving the screen is related to the size of the screen. If you use a large, medium-sized screen color TV in a small room, the left and right channel speakers can be placed close to the sides of the screen. If the screen is small, you can make them a little further away from the screen to get a wider stereo field. But don't go too far from the screen, so as not to give people a false feeling because the sound image position is too far from the picture. From this point of view, there is a shortage of "innate" - the environment is too small. In summary, the sound directivity of the left, middle and right three-channel speakers is heavier than the diffusivity, that is, the radiation angle range of the three channels should be oriented toward the optimal listening position. This reduces the effects of reflected sound from the floor, walls and roof, and properly ensures the clarity of the sound image.
3. Place the surround channel speakers
Surround speakers are used to create an atmosphere that also plays an important role in the entire speaker system.
A. Types of Surround Speakers Currently, there are two types of surround speakers, one is a common unipolar small speaker, which is usually placed on the speaker stand or hung on the wall. Another type of surround speaker is THX recommended dipole speakers, each with two back-to-back speakers installed, all connected in reverse phase. This kind of speaker only emits high-frequency sound to the front and rear and can not produce low-frequency sound (even Entering the low frequency signal and also not paying the bass due to the offset.) Why is this? Let's look at the working process of the dipole speaker. Two speakers are placed back to back in the speaker, and the two speakers are fed. In the opposite phase of the signal, the A speaker inputs a positive polarity signal, and the paper cassette moves forward, compressing the front air (increased density). At the same time, the B speaker inputs a negative polarity signal, and the low box moves backward, so that The air in front of it is sparse (reduced density), so the direction of the sound wave in front of the two speakers is opposite. If the two speakers feed in the full-band signal, the low-frequency is strong because of its long wavelength, so the low-frequency sound from the A speaker will Winding around The B-speaker is weakened (cancelled); while the medium-high frequency signal has a short diffractive power due to its short wavelength, the mid-high frequency sound on both sides of the speaker is small, so the offset effect in front of the speaker is not obvious, so two The speaker only emits low-frequency sounds in the middle and high-frequency sounds of the front and rear. The purpose of using the dipole-type speakers is to avoid excessive directionality.
For the audio industry, the dipole speaker is a very strange type. This kind of speaker needs to be developed to mature. This kind of speaker is not full frequency band, because the frequency below 100MHz has been cut off. Therefore, the speaker is used because it only sounds forward and backward at the same time and never sounds to the side where the listener is located, and the sound is heard before the listener is filled with the listening room, so that a hearing habit can be created. Surrounding sound.
B. The arrangement of the surround speakers of the surround speakers should be different depending on the listening environment (room conditions) and the type of loop speakers. The speakers of the left and right surround channels should be more diffuse than the sound. Directionality, which is conducive to create a rich surrounding atmosphere. When placing dipole-type speakers , two factors should be considered: resonance and self-fading. The best anti-resonance is 20% indoor space from the ceiling (or ground). At the height (if the indoor height is 2.5m, the best position is 50cm above and below). In order to make the frequency response smoother, a new device called low frequency "trap" (absorbing low audio) can be added to eliminate the reflection that causes the sound to decay.
For direct-radiation loop speakers, there are many options to consider. For example: fixed on the walls on both sides and pointing them to the rear corner; fixed on the rear wall, making them open and upward in an inverted figure-eight shape and Towards the junction of the side wall and the ceiling; placed on the floor against the wall on both sides, pointing upwards to the junction of the wall and the ceiling, etc. Many other options can be designed according to the specific conditions of the room. The surround sound field of the home theater is mainly indoors. Each anti-sound is formed by the acoustic reflection and refraction of the surrounding speakers, and the room acoustic conditions of different rooms vary widely. As long as the patience test and careful comparison, the best placement plan will be found.
4. The subwoofer is usually placed near the corner of the front wall, preferably more than 1m from the corner, which can reduce the interference of standing waves. You can also put the subwoofer on both sides of the best listening position. Keep the proper distance, because the human ear is not sensitive to the directionality of the subwoofers from both sides, so the subwoofer will not interfere with the original sound image localization of the front three channels. Of course, the best pendulum The placement position should still be determined by experimentation.
The method described below may be helpful in finding the best placement of the subwoofer. Place the subwoofer in the best listening position (temporarily remove the nearby debris), connect its speaker cable and play a strong bass repeatedly. The effect of the music, then carefully around the room to listen. Listen, ask the ear to stick to the ground, roughly at the height of the subwoofer. When listening, find the most stable, deepest, clearest point of the bass, that is super The best placement of the subwoofer.
With the advent of the information age, the rapid development of computer multimedia technology, the universal application of network technology, the establishment of command and control centers, network management centers, small to temporary meetings, technical lectures, are eager to get a big picture. Multi-color, high brightness. High-resolution display, while traditional CRT displays are difficult to meet people's requirements. The rapid development of large-screen projector technology in recent years has become an effective way to solve large-color display of color, and the scope of application has been further expanded, and the market has become increasingly active due to the growth of demand. We will now introduce how to choose a projector.
First, the impact of indoor acoustic environment In the multi-channel sound system, currently the most representative of Dolby Pro Logic four channels, it is still the most popular multi-channel sound system. Because the surround track uses two surrounds The channel uses two surround speakers, so the system requires five speakers. Since the advent of the Dolby AC-3 digital multichannel system, the discrete 5.1 channel has quickly become the new multi-channel standard for home theater.
The indoor acoustic environment has a certain influence on the indoor sound field created by the multi-channel speaker. Different room sounds have different spatial acoustic characteristics. The multi-channel sound system uses multiple speakers to represent the sound image and create a surround sound effect. This is not an easy task. If there is no ideal indoor acoustic environment to match, then the comprehensive sound effect will not be good. According to the theory of acoustic psychology, the early reflection sound of less than 1ms in the interior is delayed. Significant interference with direct sound will make the sound become more turbid, which will affect the sound image localization. The early reflection sound between 1~30ms will have less interference to the direct sound, and it will be combined with the direct sound. It helps to increase the loudness, but it may change the tone of the direct sound. As for the reflected sound after 30ms, the human ear usually thinks it is a reverberation sound. For the above reasons, we must do a good job of sound absorption and diffusion in the audio-visual room. Acoustic processing such as sound insulation, otherwise, excessive reverberation will reduce the clarity and consistency of the sound and affect the playback sound.
In order to illuminate the grand stereo field of the theater, the room for audio-visual use should not be too small. If possible, sound-absorbing materials should be added.
Second, the speaker is placed on the premise of a good indoor acoustic environment, the more accurate the sound image is positioned, the more realistic the sound is, the more it can show the vivid effect of the sound and image. First look at the placement of the speakers in the theater. The picture below shows the speaker layout for each channel of the actual theater with surround sound.
The left and right channel front speakers are separated from each other by almost the same distance as the movie screen. The front speakers are usually discharged behind the movie screen, and they can pass the sound to the audience through the small gap of the screen. Therefore, this speaker can be placed at half the height of the screen.
The subwoofer is not necessarily placed in a symmetrical position in the front speaker cluster;
The standard theater has a lot of surround speakers, which together with the front speakers really "surround" the audience.
After referring to the above examples of speaker placement , let's go back and see how the speakers should be placed for the best sound. Here, we have to pay attention to the problem that the indoor play space we encounter may be much smaller than the real theater. Below, we will discuss the placement of three front (left, center, and right) speakers, then surround the sound box, and finally study the placement of the subwoofer.
1. The center speaker of the center channel speaker is placed as close as possible to the center of the image screen. The center channel speaker has the greatest influence on the sound quality of the movie dialogue, in order to ensure that the dialogue is accurately positioned in the center of the screen and the sound Clearly, you should use a separate speaker designed specifically for the center channel, instead of using an ordinary bookshelf speaker or a speaker inside the TV.
Most of the center channel speakers use a horizontal horizontal box, the best place for the top of the TV (if the front projection display screen is placed behind the screen), it should be as close as possible to the screen. If it is limited by the space of the room A more economical placement scheme can be used, that is, no center speaker is provided. However, the working mode of the AV amplifier should be placed in the "phantom" channel mode, so that the information of the center channel is from the left and right speakers. Balanced release, its sound is just in the center of the screen, which is suitable for small listening rooms. Of course, it is best to set up a center speaker.
2. The placement of the left and right channel main speakers has a certain relationship with the position of the center channel speakers. In order to ensure the smoothness of the left and right movement of the sound image, they should be placed on both sides of the center channel speaker, and the three speakers should be at the same distance from the position of the best listener in front of the screen. In general, the center speaker should be placed a little longer than the left and right speakers until the sound field can be completely combined to create a truly unified sound image. The distance of the back is related to the size of the space, the listening position and the speakers used, which can be determined by experiment. In addition, the vertical height of the left and right channel speakers is preferably not higher or lower than the center speaker's axis by 0.3m (preferably slightly lower), otherwise the left, middle and right three The height difference of the speakers is too large, and the front sound image gives a sound jump when it is laterally displaced. Generally, floor-standing speakers can meet the above requirements. If you use a bookshelf speaker for the left and right speakers, you should fix them on the speaker stand so that it meets the above requirements.
The distance between the left and right channel speakers leaving the screen is related to the size of the screen. If you use a large, medium-sized screen color TV in a small room, the left and right channel speakers can be placed close to the sides of the screen. If the screen is small, you can make them a little further away from the screen to get a wider stereo field. But don't go too far from the screen, so as not to give people a false feeling because the sound image position is too far from the picture. From this point of view, there is a shortage of "innate" - the environment is too small. In summary, the sound directivity of the left, middle and right three-channel speakers is heavier than the diffusivity, that is, the radiation angle range of the three channels should be oriented toward the optimal listening position. This reduces the effects of reflected sound from the floor, walls and roof, and properly ensures the clarity of the sound image.
3. Place the surround channel speakers
Surround speakers are used to create an atmosphere that also plays an important role in the entire speaker system.
A. Types of Surround Speakers Currently, there are two types of surround speakers, one is a common unipolar small speaker, which is usually placed on the speaker stand or hung on the wall. Another type of surround speaker is THX recommended dipole speakers, each with two back-to-back speakers installed, all connected in reverse phase. This kind of speaker only emits high-frequency sound to the front and rear and can not produce low-frequency sound (even Entering the low frequency signal and also not paying the bass due to the offset.) Why is this? Let's look at the working process of the dipole speaker. Two speakers are placed back to back in the speaker, and the two speakers are fed. In the opposite phase of the signal, the A speaker inputs a positive polarity signal, and the paper cassette moves forward, compressing the front air (increased density). At the same time, the B speaker inputs a negative polarity signal, and the low box moves backward, so that The air in front of it is sparse (reduced density), so the direction of the sound wave in front of the two speakers is opposite. If the two speakers feed in the full-band signal, the low-frequency is strong because of its long wavelength, so the low-frequency sound from the A speaker will Winding around The B-speaker is weakened (cancelled); while the medium-high frequency signal has a short diffractive power due to its short wavelength, the mid-high frequency sound on both sides of the speaker is small, so the offset effect in front of the speaker is not obvious, so two The speaker only emits low-frequency sounds in the middle and high-frequency sounds of the front and rear. The purpose of using the dipole-type speakers is to avoid excessive directionality.
For the audio industry, the dipole speaker is a very strange type. This kind of speaker needs to be developed to mature. This kind of speaker is not full frequency band, because the frequency below 100MHz has been cut off. Therefore, the speaker is used because it only sounds forward and backward at the same time and never sounds to the side where the listener is located, and the sound is heard before the listener is filled with the listening room, so that a hearing habit can be created. Surrounding sound.
B. The arrangement of the surround speakers of the surround speakers should be different depending on the listening environment (room conditions) and the type of loop speakers. The speakers of the left and right surround channels should be more diffuse than the sound. Directionality, which is conducive to create a rich surrounding atmosphere. When placing dipole-type speakers , two factors should be considered: resonance and self-fading. The best anti-resonance is 20% indoor space from the ceiling (or ground). At the height (if the indoor height is 2.5m, the best position is 50cm above and below). In order to make the frequency response smoother, a new device called low frequency "trap" (absorbing low audio) can be added to eliminate the reflection that causes the sound to decay.
For direct-radiation loop speakers, there are many options to consider. For example: fixed on the walls on both sides and pointing them to the rear corner; fixed on the rear wall, making them open and upward in an inverted figure-eight shape and Towards the junction of the side wall and the ceiling; placed on the floor against the wall on both sides, pointing upwards to the junction of the wall and the ceiling, etc. Many other options can be designed according to the specific conditions of the room. The surround sound field of the home theater is mainly indoors. Each anti-sound is formed by the acoustic reflection and refraction of the surrounding speakers, and the room acoustic conditions of different rooms vary widely. As long as the patience test and careful comparison, the best placement plan will be found.
4. The subwoofer is usually placed near the corner of the front wall, preferably more than 1m from the corner, which can reduce the interference of standing waves. You can also put the subwoofer on both sides of the best listening position. Keep the proper distance, because the human ear is not sensitive to the directionality of the subwoofers from both sides, so the subwoofer will not interfere with the original sound image localization of the front three channels. Of course, the best pendulum The placement position should still be determined by experimentation.
The method described below may be helpful in finding the best placement of the subwoofer. Place the subwoofer in the best listening position (temporarily remove the nearby debris), connect its speaker cable and play a strong bass repeatedly. The effect of the music, then carefully around the room to listen. Listen, ask the ear to stick to the ground, roughly at the height of the subwoofer. When listening, find the most stable, deepest, clearest point of the bass, that is super The best placement of the subwoofer.
With the advent of the information age, the rapid development of computer multimedia technology, the universal application of network technology, the establishment of command and control centers, network management centers, small to temporary meetings, technical lectures, are eager to get a big picture. Multi-color, high brightness. High-resolution display, while traditional CRT displays are difficult to meet people's requirements. The rapid development of large-screen projector technology in recent years has become an effective way to solve large-color display of color, and the scope of application has been further expanded, and the market has become increasingly active due to the growth of demand. We will now introduce how to choose a projector.
The indoor acoustic environment has a certain influence on the indoor sound field created by the multi-channel speaker. Different room sounds have different spatial acoustic characteristics. The multi-channel sound system uses multiple speakers to represent the sound image and create a surround sound effect. This is not an easy task. If there is no ideal indoor acoustic environment to match, then the comprehensive sound effect will not be good. According to the theory of acoustic psychology, the early reflection sound of less than 1ms in the interior is delayed. Significant interference with direct sound will make the sound become more turbid, which will affect the sound image localization. The early reflection sound between 1~30ms will have less interference to the direct sound, and it will be combined with the direct sound. It helps to increase the loudness, but it may change the tone of the direct sound. As for the reflected sound after 30ms, the human ear usually thinks it is a reverberation sound. For the above reasons, we must do a good job of sound absorption and diffusion in the audio-visual room. Acoustic processing such as sound insulation, otherwise, excessive reverberation will reduce the clarity and consistency of the sound and affect the playback sound.
In order to illuminate the grand stereo field of the theater, the room for audio-visual use should not be too small. If possible, sound-absorbing materials should be added.
Second, the speaker is placed on the premise of a good indoor acoustic environment, the more accurate the sound image is positioned, the more realistic the sound is, the more it can show the vivid effect of the sound and image. First look at the placement of the speakers in the theater. The picture below shows the speaker layout for each channel of the actual theater with surround sound.
The left and right channel front speakers are separated from each other by almost the same distance as the movie screen. The front speakers are usually discharged behind the movie screen, and they can pass the sound to the audience through the small gap of the screen. Therefore, this speaker can be placed at half the height of the screen.
The subwoofer is not necessarily placed in a symmetrical position in the front speaker cluster;
The standard theater has a lot of surround speakers, which together with the front speakers really "surround" the audience.
After referring to the above examples of speaker placement , let's go back and see how the speakers should be placed for the best sound. Here, we have to pay attention to the problem that the indoor play space we encounter may be much smaller than the real theater. Below, we will discuss the placement of three front (left, center, and right) speakers, then surround the sound box, and finally study the placement of the subwoofer.
1. The center speaker of the center channel speaker is placed as close as possible to the center of the image screen. The center channel speaker has the greatest influence on the sound quality of the movie dialogue, in order to ensure that the dialogue is accurately positioned in the center of the screen and the sound Clearly, you should use a separate speaker designed specifically for the center channel, instead of using an ordinary bookshelf speaker or a speaker inside the TV.
Most of the center channel speakers use a horizontal horizontal box, the best place for the top of the TV (if the front projection display screen is placed behind the screen), it should be as close as possible to the screen. If it is limited by the space of the room A more economical placement scheme can be used, that is, no center speaker is provided. However, the working mode of the AV amplifier should be placed in the "phantom" channel mode, so that the information of the center channel is from the left and right speakers. Balanced release, its sound is just in the center of the screen, which is suitable for small listening rooms. Of course, it is best to set up a center speaker.
2. The placement of the left and right channel main speakers has a certain relationship with the position of the center channel speakers. In order to ensure the smoothness of the left and right movement of the sound image, they should be placed on both sides of the center channel speaker, and the three speakers should be at the same distance from the position of the best listener in front of the screen. In general, the center speaker should be placed a little longer than the left and right speakers until the sound field can be completely combined to create a truly unified sound image. The distance of the back is related to the size of the space, the listening position and the speakers used, which can be determined by experiment. In addition, the vertical height of the left and right channel speakers is preferably not higher or lower than the center speaker's axis by 0.3m (preferably slightly lower), otherwise the left, middle and right three The height difference of the speakers is too large, and the front sound image gives a sound jump when it is laterally displaced. Generally, floor-standing speakers can meet the above requirements. If you use a bookshelf speaker for the left and right speakers, you should fix them on the speaker stand so that it meets the above requirements.
The distance between the left and right channel speakers leaving the screen is related to the size of the screen. If you use a large, medium-sized screen color TV in a small room, the left and right channel speakers can be placed close to the sides of the screen. If the screen is small, you can make them a little further away from the screen to get a wider stereo field. But don't go too far from the screen, so as not to give people a false feeling because the sound image position is too far from the picture. From this point of view, there is a shortage of "innate" - the environment is too small. In summary, the sound directivity of the left, middle and right three-channel speakers is heavier than the diffusivity, that is, the radiation angle range of the three channels should be oriented toward the optimal listening position. This reduces the effects of reflected sound from the floor, walls and roof, and properly ensures the clarity of the sound image.
3. Place the surround channel speakers
Surround speakers are used to create an atmosphere that also plays an important role in the entire speaker system.
A. Types of Surround Speakers Currently, there are two types of surround speakers, one is a common unipolar small speaker, which is usually placed on the speaker stand or hung on the wall. Another type of surround speaker is THX recommended dipole speakers, each with two back-to-back speakers installed, all connected in reverse phase. This kind of speaker only emits high-frequency sound to the front and rear and can not produce low-frequency sound (even Entering the low frequency signal and also not paying the bass due to the offset.) Why is this? Let's look at the working process of the dipole speaker. Two speakers are placed back to back in the speaker, and the two speakers are fed. In the opposite phase of the signal, the A speaker inputs a positive polarity signal, and the paper cassette moves forward, compressing the front air (increased density). At the same time, the B speaker inputs a negative polarity signal, and the low box moves backward, so that The air in front of it is sparse (reduced density), so the direction of the sound wave in front of the two speakers is opposite. If the two speakers feed in the full-band signal, the low-frequency is strong because of its long wavelength, so the low-frequency sound from the A speaker will Winding around The B-speaker is weakened (cancelled); while the medium-high frequency signal has a short diffractive power due to its short wavelength, the mid-high frequency sound on both sides of the speaker is small, so the offset effect in front of the speaker is not obvious, so two The speaker only emits low-frequency sounds in the middle and high-frequency sounds of the front and rear. The purpose of using the dipole-type speakers is to avoid excessive directionality.
For the audio industry, the dipole speaker is a very strange type. This kind of speaker needs to be developed to mature. This kind of speaker is not full frequency band, because the frequency below 100MHz has been cut off. Therefore, the speaker is used because it only sounds forward and backward at the same time and never sounds to the side where the listener is located, and the sound is heard before the listener is filled with the listening room, so that a hearing habit can be created. Surrounding sound.
B. The arrangement of the surround speakers of the surround speakers should be different depending on the listening environment (room conditions) and the type of loop speakers. The speakers of the left and right surround channels should be more diffuse than the sound. Directionality, which is conducive to create a rich surrounding atmosphere. When placing dipole-type speakers , two factors should be considered: resonance and self-fading. The best anti-resonance is 20% indoor space from the ceiling (or ground). At the height (if the indoor height is 2.5m, the best position is 50cm above and below). In order to make the frequency response smoother, a new device called low frequency "trap" (absorbing low audio) can be added to eliminate the reflection that causes the sound to decay.
For direct-radiation loop speakers, there are many options to consider. For example: fixed on the walls on both sides and pointing them to the rear corner; fixed on the rear wall, making them open and upward in an inverted figure-eight shape and Towards the junction of the side wall and the ceiling; placed on the floor against the wall on both sides, pointing upwards to the junction of the wall and the ceiling, etc. Many other options can be designed according to the specific conditions of the room. The surround sound field of the home theater is mainly indoors. Each anti-sound is formed by the acoustic reflection and refraction of the surrounding speakers, and the room acoustic conditions of different rooms vary widely. As long as the patience test and careful comparison, the best placement plan will be found.
4. The subwoofer is usually placed near the corner of the front wall, preferably more than 1m from the corner, which can reduce the interference of standing waves. You can also put the subwoofer on both sides of the best listening position. Keep the proper distance, because the human ear is not sensitive to the directionality of the subwoofers from both sides, so the subwoofer will not interfere with the original sound image localization of the front three channels. Of course, the best pendulum The placement position should still be determined by experimentation.
The method described below may be helpful in finding the best placement of the subwoofer. Place the subwoofer in the best listening position (temporarily remove the nearby debris), connect its speaker cable and play a strong bass repeatedly. The effect of the music, then carefully around the room to listen. Listen, ask the ear to stick to the ground, roughly at the height of the subwoofer. When listening, find the most stable, deepest, clearest point of the bass, that is super The best placement of the subwoofer.
With the advent of the information age, the rapid development of computer multimedia technology, the universal application of network technology, the establishment of command and control centers, network management centers, small to temporary meetings, technical lectures, are eager to get a big picture. Multi-color, high brightness. High-resolution display, while traditional CRT displays are difficult to meet people's requirements. The rapid development of large-screen projector technology in recent years has become an effective way to solve large-color display of color, and the scope of application has been further expanded, and the market has become increasingly active due to the growth of demand. We will now introduce how to choose a projector.
First, the impact of indoor acoustic environment In the multi-channel sound system, currently the most representative of Dolby Pro Logic four channels, it is still the most popular multi-channel sound system. Because the surround track uses two surrounds The channel uses two surround speakers, so the system requires five speakers. Since the advent of the Dolby AC-3 digital multichannel system, the discrete 5.1 channel has quickly become the new multi-channel standard for home theater.
The indoor acoustic environment has a certain influence on the indoor sound field created by the multi-channel speaker. Different room sounds have different spatial acoustic characteristics. The multi-channel sound system uses multiple speakers to represent the sound image and create a surround sound effect. This is not an easy task. If there is no ideal indoor acoustic environment to match, then the comprehensive sound effect will not be good. According to the theory of acoustic psychology, the early reflection sound of less than 1ms in the interior is delayed. Significant interference with direct sound will make the sound become more turbid, which will affect the sound image localization. The early reflection sound between 1~30ms will have less interference to the direct sound, and it will be combined with the direct sound. It helps to increase the loudness, but it may change the tone of the direct sound. As for the reflected sound after 30ms, the human ear usually thinks it is a reverberation sound. For the above reasons, we must do a good job of sound absorption and diffusion in the audio-visual room. Acoustic processing such as sound insulation, otherwise, excessive reverberation will reduce the clarity and consistency of the sound and affect the playback sound.
In order to illuminate the grand stereo field of the theater, the room for audio-visual use should not be too small. If possible, sound-absorbing materials should be added.
Second, the speaker is placed on the premise of a good indoor acoustic environment, the more accurate the sound image is positioned, the more realistic the sound is, the more it can show the vivid effect of the sound and image. First look at the placement of the speakers in the theater. The picture below shows the speaker layout for each channel of the actual theater with surround sound.
The left and right channel front speakers are separated from each other by almost the same distance as the movie screen. The front speakers are usually discharged behind the movie screen, and they can pass the sound to the audience through the small gap of the screen. Therefore, this speaker can be placed at half the height of the screen.
The subwoofer is not necessarily placed in a symmetrical position in the front speaker cluster;
The standard theater has a lot of surround speakers, which together with the front speakers really "surround" the audience.
After referring to the above examples of speaker placement , let's go back and see how the speakers should be placed for the best sound. Here, we have to pay attention to the problem that the indoor play space we encounter may be much smaller than the real theater. Below, we will discuss the placement of three front (left, center, and right) speakers, then surround the sound box, and finally study the placement of the subwoofer.
1. The center speaker of the center channel speaker is placed as close as possible to the center of the image screen. The center channel speaker has the greatest influence on the sound quality of the movie dialogue, in order to ensure that the dialogue is accurately positioned in the center of the screen and the sound Clearly, you should use a separate speaker designed specifically for the center channel, instead of using an ordinary bookshelf speaker or a speaker inside the TV.
Most of the center channel speakers use a horizontal horizontal box, the best place for the top of the TV (if the front projection display screen is placed behind the screen), it should be as close as possible to the screen. If it is limited by the space of the room A more economical placement scheme can be used, that is, no center speaker is provided. However, the working mode of the AV amplifier should be placed in the "phantom" channel mode, so that the information of the center channel is from the left and right speakers. Balanced release, its sound is just in the center of the screen, which is suitable for small listening rooms. Of course, it is best to set up a center speaker.
2. The placement of the left and right channel main speakers has a certain relationship with the position of the center channel speakers. In order to ensure the smoothness of the left and right movement of the sound image, they should be placed on both sides of the center channel speaker, and the three speakers should be at the same distance from the position of the best listener in front of the screen. In general, the center speaker should be placed a little longer than the left and right speakers until the sound field can be completely combined to create a truly unified sound image. The distance of the back is related to the size of the space, the listening position and the speakers used, which can be determined by experiment. In addition, the vertical height of the left and right channel speakers is preferably not higher or lower than the center speaker's axis by 0.3m (preferably slightly lower), otherwise the left, middle and right three The height difference of the speakers is too large, and the front sound image gives a sound jump when it is laterally displaced. Generally, floor-standing speakers can meet the above requirements. If you use a bookshelf speaker for the left and right speakers, you should fix them on the speaker stand so that it meets the above requirements.
The distance between the left and right channel speakers leaving the screen is related to the size of the screen. If you use a large, medium-sized screen color TV in a small room, the left and right channel speakers can be placed close to the sides of the screen. If the screen is small, you can make them a little further away from the screen to get a wider stereo field. But don't go too far from the screen, so as not to give people a false feeling because the sound image position is too far from the picture. From this point of view, there is a shortage of "innate" - the environment is too small. In summary, the sound directivity of the left, middle and right three-channel speakers is heavier than the diffusivity, that is, the radiation angle range of the three channels should be oriented toward the optimal listening position. This reduces the effects of reflected sound from the floor, walls and roof, and properly ensures the clarity of the sound image.
3. Place the surround channel speakers
Surround speakers are used to create an atmosphere that also plays an important role in the entire speaker system.
A. Types of Surround Speakers Currently, there are two types of surround speakers, one is a common unipolar small speaker, which is usually placed on the speaker stand or hung on the wall. Another type of surround speaker is THX recommended dipole speakers, each with two back-to-back speakers installed, all connected in reverse phase. This kind of speaker only emits high-frequency sound to the front and rear and can not produce low-frequency sound (even Entering the low frequency signal and also not paying the bass due to the offset.) Why is this? Let's look at the working process of the dipole speaker. Two speakers are placed back to back in the speaker, and the two speakers are fed. In the opposite phase of the signal, the A speaker inputs a positive polarity signal, and the paper cassette moves forward, compressing the front air (increased density). At the same time, the B speaker inputs a negative polarity signal, and the low box moves backward, so that The air in front of it is sparse (reduced density), so the direction of the sound wave in front of the two speakers is opposite. If the two speakers feed in the full-band signal, the low-frequency is strong because of its long wavelength, so the low-frequency sound from the A speaker will Winding around The B-speaker is weakened (cancelled); while the medium-high frequency signal has a short diffractive power due to its short wavelength, the mid-high frequency sound on both sides of the speaker is small, so the offset effect in front of the speaker is not obvious, so two The speaker only emits low-frequency sounds in the middle and high-frequency sounds of the front and rear. The purpose of using the dipole-type speakers is to avoid excessive directionality.
For the audio industry, the dipole speaker is a very strange type. This kind of speaker needs to be developed to mature. This kind of speaker is not full frequency band, because the frequency below 100MHz has been cut off. Therefore, the speaker is used because it only sounds forward and backward at the same time and never sounds to the side where the listener is located, and the sound is heard before the listener is filled with the listening room, so that a hearing habit can be created. Surrounding sound.
B. The arrangement of the surround speakers of the surround speakers should be different depending on the listening environment (room conditions) and the type of loop speakers. The speakers of the left and right surround channels should be more diffuse than the sound. Directionality, which is conducive to create a rich surrounding atmosphere. When placing dipole-type speakers , two factors should be considered: resonance and self-fading. The best anti-resonance is 20% indoor space from the ceiling (or ground). At the height (if the indoor height is 2.5m, the best position is 50cm above and below). In order to make the frequency response smoother, a new device called low frequency "trap" (absorbing low audio) can be added to eliminate the reflection that causes the sound to decay.
For direct-radiation loop speakers, there are many options to consider. For example: fixed on the walls on both sides and pointing them to the rear corner; fixed on the rear wall, making them open and upward in an inverted figure-eight shape and Towards the junction of the side wall and the ceiling; placed on the floor against the wall on both sides, pointing upwards to the junction of the wall and the ceiling, etc. Many other options can be designed according to the specific conditions of the room. The surround sound field of the home theater is mainly indoors. Each anti-sound is formed by the acoustic reflection and refraction of the surrounding speakers, and the room acoustic conditions of different rooms vary widely. As long as the patience test and careful comparison, the best placement plan will be found.
4. The subwoofer is usually placed near the corner of the front wall, preferably more than 1m from the corner, which can reduce the interference of standing waves. You can also put the subwoofer on both sides of the best listening position. Keep the proper distance, because the human ear is not sensitive to the directionality of the subwoofers from both sides, so the subwoofer will not interfere with the original sound image localization of the front three channels. Of course, the best pendulum The placement position should still be determined by experimentation.
The method described below may be helpful in finding the best placement of the subwoofer. Place the subwoofer in the best listening position (temporarily remove the nearby debris), connect its speaker cable and play a strong bass repeatedly. The effect of the music, then carefully around the room to listen. Listen, ask the ear to stick to the ground, roughly at the height of the subwoofer. When listening, find the most stable, deepest, clearest point of the bass, that is super The best placement of the subwoofer.
With the advent of the information age, the rapid development of computer multimedia technology, the universal application of network technology, the establishment of command and control centers, network management centers, small to temporary meetings, technical lectures, are eager to get a big picture. Multi-color, high brightness. High-resolution display, while traditional CRT displays are difficult to meet people's requirements. The rapid development of large-screen projector technology in recent years has become an effective way to solve large-color display of color, and the scope of application has been further expanded, and the market has become increasingly active due to the growth of demand. We will now introduce how to choose a projector.
First, the impact of indoor acoustic environment In the multi-channel sound system, currently the most representative of Dolby Pro Logic four channels, it is still the most popular multi-channel sound system. Because the surround track uses two surrounds The channel uses two surround speakers, so the system requires five speakers. Since the advent of the Dolby AC-3 digital multichannel system, the discrete 5.1 channel has quickly become the new multi-channel standard for home theater.
The indoor acoustic environment has a certain influence on the indoor sound field created by the multi-channel speaker. Different room sounds have different spatial acoustic characteristics. The multi-channel sound system uses multiple speakers to represent the sound image and create a surround sound effect. This is not an easy task. If there is no ideal indoor acoustic environment to match, then the comprehensive sound effect will not be good. According to the theory of acoustic psychology, the early reflection sound of less than 1ms in the interior is delayed. Significant interference with direct sound will make the sound become more turbid, which will affect the sound image localization. The early reflection sound between 1~30ms will have less interference to the direct sound, and it will be combined with the direct sound. It helps to increase the loudness, but it may change the tone of the direct sound. As for the reflected sound after 30ms, the human ear usually thinks it is a reverberation sound. For the above reasons, we must do a good job of sound absorption and diffusion in the audio-visual room. Acoustic processing such as sound insulation, otherwise, excessive reverberation will reduce the clarity and consistency of the sound and affect the playback sound.
In order to illuminate the grand stereo field of the theater, the room for audio-visual use should not be too small. If possible, sound-absorbing materials should be added.
Second, the speaker is placed on the premise of a good indoor acoustic environment, the more accurate the sound image is positioned, the more realistic the sound is, the more it can show the vivid effect of the sound and image. First look at the placement of the speakers in the theater. The picture below shows the speaker layout for each channel of the actual theater with surround sound.
The left and right channel front speakers are separated from each other by almost the same distance as the movie screen. The front speakers are usually discharged behind the movie screen, and they can pass the sound to the audience through the small gap of the screen. Therefore, this speaker can be placed at half the height of the screen.
The subwoofer is not necessarily placed in a symmetrical position in the front speaker cluster;
The standard theater has a lot of surround speakers, which together with the front speakers really "surround" the audience.
After referring to the above examples of speaker placement , let's go back and see how the speakers should be placed for the best sound. Here, we have to pay attention to the problem that the indoor play space we encounter may be much smaller than the real theater. Below, we will discuss the placement of three front (left, center, and right) speakers, then surround the sound box, and finally study the placement of the subwoofer.
1. The center speaker of the center channel speaker is placed as close as possible to the center of the image screen. The center channel speaker has the greatest influence on the sound quality of the movie dialogue, in order to ensure that the dialogue is accurately positioned in the center of the screen and the sound Clearly, you should use a separate speaker designed specifically for the center channel, instead of using an ordinary bookshelf speaker or a speaker inside the TV.
Most of the center channel speakers use a horizontal horizontal box, the best place for the top of the TV (if the front projection display screen is placed behind the screen), it should be as close as possible to the screen. If it is limited by the space of the room A more economical placement scheme can be used, that is, no center speaker is provided. However, the working mode of the AV amplifier should be placed in the "phantom" channel mode, so that the information of the center channel is from the left and right speakers. Balanced release, its sound is just in the center of the screen, which is suitable for small listening rooms. Of course, it is best to set up a center speaker.
2. The placement of the left and right channel main speakers has a certain relationship with the position of the center channel speakers. In order to ensure the smoothness of the left and right movement of the sound image, they should be placed on both sides of the center channel speaker, and the three speakers should be at the same distance from the position of the best listener in front of the screen. In general, the center speaker should be placed a little longer than the left and right speakers until the sound field can be completely combined to create a truly unified sound image. The distance of the back is related to the size of the space, the listening position and the speakers used, which can be determined by experiment. In addition, the vertical height of the left and right channel speakers is preferably not higher or lower than the center speaker's axis by 0.3m (preferably slightly lower), otherwise the left, middle and right three The height difference of the speakers is too large, and the front sound image gives a sound jump when it is laterally displaced. Generally, floor-standing speakers can meet the above requirements. If you use a bookshelf speaker for the left and right speakers, you should fix them on the speaker stand so that it meets the above requirements.
The distance between the left and right channel speakers leaving the screen is related to the size of the screen. If you use a large, medium-sized screen color TV in a small room, the left and right channel speakers can be placed close to the sides of the screen. If the screen is small, you can make them a little further away from the screen to get a wider stereo field. But don't go too far from the screen, so as not to give people a false feeling because the sound image position is too far from the picture. From this point of view, there is a shortage of "innate" - the environment is too small. In summary, the sound directivity of the left, middle and right three-channel speakers is heavier than the diffusivity, that is, the radiation angle range of the three channels should be oriented toward the optimal listening position. This reduces the effects of reflected sound from the floor, walls and roof, and properly ensures the clarity of the sound image.
3. Place the surround channel speakers
Surround speakers are used to create an atmosphere that also plays an important role in the entire speaker system.
A. Types of Surround Speakers Currently, there are two types of surround speakers, one is a common unipolar small speaker, which is usually placed on the speaker stand or hung on the wall. Another type of surround speaker is THX recommended dipole speakers, each with two back-to-back speakers installed, all connected in reverse phase. This kind of speaker only emits high-frequency sound to the front and rear and can not produce low-frequency sound (even Entering the low frequency signal and also not paying the bass due to the offset.) Why is this? Let's look at the working process of the dipole speaker. Two speakers are placed back to back in the speaker, and the two speakers are fed. In the opposite phase of the signal, the A speaker inputs a positive polarity signal, and the paper cassette moves forward, compressing the front air (increased density). At the same time, the B speaker inputs a negative polarity signal, and the low box moves backward, so that The air in front of it is sparse (reduced density), so the direction of the sound wave in front of the two speakers is opposite. If the two speakers feed in the full-band signal, the low-frequency is strong because of its long wavelength, so the low-frequency sound from the A speaker will Winding around The B-speaker is weakened (cancelled); while the medium-high frequency signal has a short diffractive power due to its short wavelength, the mid-high frequency sound on both sides of the speaker is small, so the offset effect in front of the speaker is not obvious, so two The speaker only emits low-frequency sounds in the middle and high-frequency sounds of the front and rear. The purpose of using the dipole-type speakers is to avoid excessive directionality.
For the audio industry, the dipole speaker is a very strange type. This kind of speaker needs to be developed to mature. This kind of speaker is not full frequency band, because the frequency below 100MHz has been cut off. Therefore, the speaker is used because it only sounds forward and backward at the same time and never sounds to the side where the listener is located, and the sound is heard before the listener is filled with the listening room, so that a hearing habit can be created. Surrounding sound.
B. The arrangement of the surround speakers of the surround speakers should be different depending on the listening environment (room conditions) and the type of loop speakers. The speakers of the left and right surround channels should be more diffuse than the sound. Directionality, which is conducive to create a rich surrounding atmosphere. When placing dipole-type speakers , two factors should be considered: resonance and self-fading. The best anti-resonance is 20% indoor space from the ceiling (or ground). At the height (if the indoor height is 2.5m, the best position is 50cm above and below). In order to make the frequency response smoother, a new device called low frequency "trap" (absorbing low audio) can be added to eliminate the reflection that causes the sound to decay.
For direct-radiation loop speakers, there are many options to consider. For example: fixed on the walls on both sides and pointing them to the rear corner; fixed on the rear wall, making them open and upward in an inverted figure-eight shape and Towards the junction of the side wall and the ceiling; placed on the floor against the wall on both sides, pointing upwards to the junction of the wall and the ceiling, etc. Many other options can be designed according to the specific conditions of the room. The surround sound field of the home theater is mainly indoors. Each anti-sound is formed by the acoustic reflection and refraction of the surrounding speakers, and the room acoustic conditions of different rooms vary widely. As long as the patience test and careful comparison, the best placement plan will be found.
4. The subwoofer is usually placed near the corner of the front wall, preferably more than 1m from the corner, which can reduce the interference of standing waves. You can also put the subwoofer on both sides of the best listening position. Keep the proper distance, because the human ear is not sensitive to the directionality of the subwoofers from both sides, so the subwoofer will not interfere with the original sound image localization of the front three channels. Of course, the best pendulum The placement position should still be determined by experimentation.
The method described below may be helpful in finding the best placement of the subwoofer. Place the subwoofer in the best listening position (temporarily remove the nearby debris), connect its speaker cable and play a strong bass repeatedly. The effect of the music, then carefully around the room to listen. Listen, ask the ear to stick to the ground, roughly at the height of the subwoofer. When listening, find the most stable, deepest, clearest point of the bass, that is super The best placement of the subwoofer.
With the advent of the information age, the rapid development of computer multimedia technology, the universal application of network technology, the establishment of command and control centers, network management centers, small to temporary meetings, technical lectures, are eager to get a big picture. Multi-color, high brightness. High-resolution display, while traditional CRT displays are difficult to meet people's requirements. The rapid development of large-screen projector technology in recent years has become an effective way to solve large-color display of color, and the scope of application has been further expanded, and the market has become increasingly active due to the growth of demand. We will now introduce how to choose a projector.
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