What's wrong with acoustics -Ten Questions and Ten Answers about Acoustics

Stereos are usually placed on both sides of the TV in the living room, but I don't think it looks good, and it feels easy to fall off, especially when children touch and bump. Now I want to make another TV cabinet, especially an audio cabinet to put the audio in, but the audio seller says no, which will affect the effect. I wonder if you have any better design methods. The TV is wall-mounted and the stereo is bookshelf-style. What is the definition of bookshelf speakers? Small enough to put on a bookshelf? In fact, the bookcase box should have been placed on a strong enough iron shelf, which can be purchased. If it's a fever-grade iron shelf, a pair of 2K won't stop at all. It can also be made by itself, or quartz sand can be filled in the hollow tube to increase the weight and stability. It is generally believed that when the speaker is connected to a tripod, nails are more likely to conduct harmful vibration, and rubber pads can also be simply considered. The most obvious thing after wearing a good tripod is that the sound is more stable and the low frequency is clearer.

It's on display! If it is the sound of a guide hole (airflow hole), you should pay attention. If the hole faces forward, there is no problem. If you are facing back, the distance from the back wall is very important. The closer to the low frequency, the stronger it will be. This will achieve a balance. There are so many low frequencies in the bookcase at most. Deliberate enhancement can only lead to low frequency confusion, and only moderate enhancement is right. One more thing: the farther away any sound is from the back wall, the deeper the sound field will be, the better!

The distance between the sound and the side wall is usually equal to ensure the balance between the left and right sounds. Different sound designs have different distances from the side walls, so they should be adjusted according to their actual situation.

If the concave angle is inward, a clearer imaging force can be obtained in a small environment, so that the emperor is located behind the intersection of axes. Appropriately outward (to the maximum extent) can obtain a wider sound field.

And most basically, in a rectangular room, it is best to put the stereo on the narrow side.

How to install, debug and maintain the audio equipment of high-end karaoke bars, including software, hardware and network? Daily maintenance and use of audio equipment Scientific maintenance of audio equipment is the key to extend its life. The following are some basic knowledge of daily maintenance:

1, and the normal working temperature of audio equipment should be 18℃ ~ 45℃. Too low temperature will reduce the sensitivity of some machines (such as electron tube machines); If it is too high, it is easy to burn out the components or make the components age prematurely. In summer, we should pay special attention to cooling and keep the air circulating.

2, audio equipment to avoid direct sunlight, but also to avoid close to heat sources, such as heaters.

3. After using the audio equipment, the function keys should be reset. If the function key is not reset for a long time, its pull button spring will be in a stressed state for a long time, which is easy to cause dysfunction.

4. Before turning on the audio power supply, adjust the volume potentiometer of the power amplifier to the minimum, which is one of the most effective protection means for the power amplifier and speakers. At this time, the power amplification of the power amplifier is almost zero, at least in the case of misoperation, it will not cause harm to the speaker.

5. Turn on the CD player from front to back, that is, turn on the CD player first, then turn on the front stage and the back stage, and adjust the volume potentiometer of the power amplifier to the minimum when turning on. Turn off the power amplifier first and then turn it off, so that the amplification function of the power amplifier is completely turned off. At this point, when you turn off the front-end equipment again, no matter how big the surge current is, it will not affect the power amplifier and speakers. Similarly, when turning off the power amplifier, set the volume potentiometer to the minimum, and turn it off or put it back before turning it off.

6, the machine should be commonly used. Commonly used can prolong the life of the machine, such as some parts with motors (recording stand, CD player, CD player, etc.). ). If you don't turn for a long time, some parts will be deformed.

7. Start the machine regularly. In the case of long-term non-use, especially in humid and high-temperature seasons, it is best to electrify for half an hour every day. In this way, the heat generated by the components in the machine can be used to drive away moisture, internal coils, speaker voice coils, transformers and so on. It can be prevented from being damaged by moisture.

8. Every once in a while, wipe the machine surface with clean and moist soft cotton cloth; When not in use, cover the machine with a dust cover or cloth to prevent dust from entering.

9. According to the principle of electronics, any electronic equipment should not be connected or disconnected with other equipment when it is working live. I think all my friends can understand that it is very dangerous for active devices to plug and play with electricity. Even passive devices like microphones do not advocate plug and play with electricity. Need to be reminded, never turn on the power amplifier to connect the speaker wire, because the terminals of the speaker are generally very close, and the speaker wires are two closely parallel. When wiring, the speaker cable is often accidentally short-circuited, and the consequence is that the power amplifier will be burned out quickly. Although some power amplifiers are equipped with protection circuits, some HI-FI pure power amplifiers often omit this part of protection measures in order to improve the sound quality and reduce unnecessary sound pollution. Therefore, the phrase "turn off the power and reconnect" has long been a rule that enthusiasts must abide by.

10, some exquisite enthusiasts will not turn up the volume and play some pop music when the power amplifier is turned on. The reason is that the power amplifier element is in a cold state when it is just turned on, so it will shorten its life if it works with high current. Therefore, some enthusiasts just play some light music within half an hour of starting the machine, listen to the music at a moderate volume, and then turn up the volume to enjoy it after the machine is warmed up.

What is Dolby Audio? In the past, we knew that a hi-fi system had two speakers. This system can make people feel a kind of stereo sound in the left and right directions, but it is only flat stereo sound, which can't produce sound changes before and after.

In order to produce stereo sound with different shades, two surround speakers are added at the back, and some signals are taken out from the left and right channels through circuit changes, and then released through the rear surround speakers after processing.

Another higher level surround sound is dolby surround (also known as Dolby Stereo). This kind of surround sound was introduced by Dolby Laboratories in America. Five speakers need to be equipped in front, left, middle and right, and left and right behind. * * * produces information of four channels: left, middle, right and surround, in which the two speakers at the back are just a parallel mono signal, and there is no distinction between left and right surround.

The address of Dolby surround is the same as Dolby stereo, but it emphasizes the sound different from other ways. But what is Dolby directional logic? In fact, it is not a new Dolby stereo system, and the directional logic is aimed at decoding technology.

Dolby stereo is a kind of digital stereo with coding technology, and the decoding technology adopts a direction identification circuit or a direction logic circuit, so any sound using Dolby company circuit technology is called Dolby direction logic sound; A decoder with specific decoding technology proprietary to Dolby Company is called Dolby Directional Logic Decoder.

Of course, only when you use the AV amplifier with Dolby logic function to play the software recorded by dolby pro logic can you hear the true hi-fi digital stereo effect.

What's the difference between a speaker and a stereo? How to define. Now the computer speakers. Some targets are multimedia active speakers, and some are multimedia active audio. And merchants will say that the sound is better than the speaker. What is the difference? My friend, to put it simply, the current home audio system (high-definition audio playback system) is generally composed of CD players (VCD, DVD, MD, card stand, etc.). ), high-quality power amplifier (referred to as power amplifier, including preamplifier, post amplifier, combined amplifier, electron tube amplifier, AV amplifier, etc. ) and advanced speakers.

Obviously, the speaker is a part of the sound system. In the stereo, it can't be sold separately, but in sets. In the advanced sound combination, it can be bought and sold as a single item.

At present, the speakers used in computers are generally called multimedia speakers, but there are no multimedia speakers because they can't reach the index elements of audio high-fidelity restoration and playback. Labeling like that is his business, just like selling ordinary active speakers into advanced audio; A dozen square meters of pavement dare to weigh? Center; Dare to call a shop of more than 20 square meters? Commercial city, to name a few, is a joke, but you have to experience it yourself.

The sound restored by multimedia speakers is far from the sound. A good set of music or AV speakers and their combinations cost nearly 10,000 yuan or more, which is beyond the reach of multimedia speakers with several hundred yuan.

Active speaker refers to the speaker's own power amplifier (most 2. 1 speakers set the power amplifier in the bass speaker, and the power protection of the 2.0 speaker is set in one of them), so that the speaker can play when connected with the input audio signal.

A good stereo will never be like this. It needs a good amplifier to match it. A good amplifier is more than several thousand yuan. Of course, the multimedia speakers of regular manufacturers are used as computers, and most of them are still good.

The sound quality of speakers can't be judged only by the price. You should listen and compare more, or find someone who knows the ropes to help you choose, mainly because you like it, and you must not just listen to the merchants. From the experience, it is for reference only.

Is it appropriate to listen to disco music with KTV stereo? What stereo is suitable for listening to disco? KTV audio and stage audio are quasi-professional or professional audio. In contrast, it is a home stereo.

The main characteristics of professional audio are high power, perfect internal protection circuit and adaptability to long working hours and harsh working environment. As far as sound quality is concerned, professional audio is not necessarily better than home audio. Profession does not mean high-grade, nor does it mean good sound quality.

It's not bad to listen to Qu Di with KTV stereo. Qu Di mainly emphasizes an atmosphere, and high and low voices need to be strong, which is the strength of KTV audio. The power of the stage stereo will be higher. I don't think I need it if I listen to it myself. The sound pressure provided by the stage stereo is enough to open a nightclub.

Recently, I bought a pair of domestic ones because I like singing. But I don't know if the stereo is good. If you want to know whether the stereo you bought is good or not, you can weigh it yourself. Generally speaking, professional audio can be seen from the weight compared with ordinary audio. Professional audio speakers are heavier than ordinary audio speakers because of their large watts and large magnetic columns. Professional speakers have a large number of tiles and great vibration, so the quality of speakers is heavier than ordinary ones, the plates are good, and the sound insulation and design are very elegant. The above is only from the appearance and other aspects of observation. For reference only, it needs to be determined according to other characteristics of the speaker and personal preference for timbre.

As for power amplifier, built-in and external have their own advantages.

Built-in does not take up space, and the connecting line with the speaker is short and the resistance is small, but the built-in heat dissipation is insufficient, because the power amplifier circuit board is mostly installed near the sound guide hole, which will interfere with the sound emitted by the audio and cause slight distortion of the sound. Secondly, because it is installed in a sound box, the circuit board will be smaller than the external one, so the power is not as good as the external one. The tuning is not as satisfactory as that of the external player.

External type has the characteristics of good heat dissipation, high power and accurate tuning because it will not limit the volume too much. In domestic household external power amplifier, its disadvantage is that it takes up a lot of space. Generally speaking, these two power amplifiers have their own advantages. Personally, I think it's better to be external!

There is no qualitative difference between turning up the volume on the computer and the stereo. Just pay attention to the following questions:

◎ If you choose to adjust mainly on the computer.

Suitable for watching movies, listening to music and other things that can easily adjust the volume in the current window.

Suitable for stereo with volume adjustment button on the back.

It is suitable for the case that the volume adjustment key is located on the back of the stereo, but there is a volume adjustment key on the keyboard.

Don't turn the volume adjustment button to the maximum, because it seems that you can get the maximum volume adjustment range, but the problem is that on many speakers, the maximum scale is already within the overload range of the amplifier. If you input a large dynamic, it is likely to burn out the speaker. Moreover, the power amplifier circuit only works well in a range, and it has been seriously distorted at the maximum power.

◎ If you choose to give priority to audio adjustment.

Suitable for playing games and other situations where the current window has no volume adjustment settings and needs to be adjusted in the options.

The volume knob is located on the front or side of the stereo.

There is no volume adjustment key on the keyboard.

Use a remote control with stereo.

Therefore, which mode to choose mainly depends on your own specific situation. Generally speaking, if you choose the computer-based mode, the sound should not exceed 70%. If you choose a combination of the two, turn it down by about 50%.

Second, about distortion.

In fact, the problem of distortion, we must first know what distortion is. Distortion is the difference between the amplified signal and the original signal, which is called distortion. Its unit is percentage. That is, the degree of "sound staining" of the speaker to the signal.

For multimedia speakers, some distortion is not a bad thing, but it should be within a reasonable range. Generally speaking, the distortion of multimedia speakers should not be greater than 1%, and the subwoofer is special, and 5% is enough.

From this point of view, distortion is closely related to sound quality. For a certain sound, the louder the volume, that is? Signal amplification? The louder the noise, the greater the distortion.

From this point of view, it is not recommended to turn the volume of the speaker very loud, and the adjustment of the computer is very small. If the old speakers are too troublesome, it is suggested to combine them, for example, the speaker volume is 40% to 50%, and then the computer volume is between 70% and 100%.

Finally, for the protection of speakers, we should also pay attention to two points. One is not to turn the volume too fast, especially when it is turned up. The other is that it is best to adjust the volume of the speaker to the minimum before turning off the stereo every time, and then adjust it to the appropriate position after turning it on every time, otherwise the influence on the speaker will be too great.