What is the principle of sound box?

The sound box consists of several main structures, such as box, sound box, frequency divider, conduit and sound-absorbing cotton. Here are the functions of each part:

Box:

The main function of the box is not to fix the horn, nor is it for beauty. When the horn vibrates, the front will emit sound, and the back will emit the same amount but opposite in phase. If the horn exists alone, the sound with opposite phase before and after will bypass the edge of the horn and produce a short circuit. The most direct consequence is that the sound becomes very small, with almost no low frequency. So we need a structure to isolate the sound before and after the speaker, which is the biggest function of the box. Designing a sound box is a complicated task. First, the shape should minimize the multiple reflections of the sound inside, so that the three sides (length, width and height) of the speaker cannot be the same length. In addition, according to the vibration characteristics of the box, in order to make the speaker play its best role, it is necessary to have a reasonable volume. Of course, there are many others that I won't introduce one by one.

Horn:

The loudspeaker is a sound generating unit, which is responsible for converting electrical signals into sound signals and transmitting them. Speakers are divided into treble, treble, alto, bass and subwoofer. There are two speakers on our common speaker, usually a tweeter and a woofer. The structure of the horn and the material of the diaphragm (metal, paper, silk, ceramics, etc.). ) determines the timbre of the speaker. The metal diaphragm is crisp and clean, and the silk diaphragm is soft and smooth (there are exceptions in general).

Frequency divider:

Because there is more than one speaker in the sound box, each speaker is responsible for different frequency playback, then there must be a circuit to separate the frequencies, that is, the frequency divider. The frequency divider uses the frequency characteristics of capacitance and inductance to divide frequency cooperatively, and there will also be resistors in the frequency divider, which are mostly used for attenuation (speakers with the same power have different output capabilities, so one of them must be attenuated). In the process of technological progress, active frequency division has also appeared (the frequency division circuit is designed in the front stage of the power amplifier), because it is not the internal structure of the speaker, so I won't go into details.

Guide sleeve:

Speakers can be divided into two types: enclosed speakers and phase-guided speakers. Phase-guided loudspeaker can export part of the sound inside the loudspeaker to increase the power of the loudspeaker and improve the low-frequency effect. The design of the conduit is also troublesome, because its position, thickness, length and shape have great influence on the sound, so it can be adjusted gradually in the process of designing the speaker to achieve the best effect.

Acoustic cotton:

The sound-absorbing cotton in the sound box is not used to destroy the sound, but to reflect the sound. Because the box volume of some speakers can't meet the required volume of speakers, we need to find ways to effectively expand the volume. This is what sound-absorbing cotton is used for. The sound signal is reflected between the fibers of the sound-absorbing cotton, and increasing the reflection distance can effectively increase the volume of the box, so the smaller the speaker is designed (according to the equivalent volume of the speaker), the more sound-absorbing cotton needs to be added.

There is also a dustproof net to prevent dust, which will also reduce the sharpness of the horn. Terminals are used for wiring, and internal wires are used to connect terminals, frequency dividers and speakers.

The above is the most basic structure of a speaker, just a brief introduction, hoping to provide you with some help.

Family statement, for reference only.

This problem seems simple, but it is actually very big! There used to be a saying that "the speaker is inconclusive"! In other words, there is no set of theories to determine how speakers should be manufactured and tested ... so the speakers on the market are really varied and strange, and the speaker design is exaggerated. Finally, it depends on feelings! Some people like a little more bass, and some people like a little more treble, but in general, I think, language category: the bass is weaker, so you can hear it clearly; Music: Like a cello solo. You should give it more bass to make it sound better.

About the principle of the speaker, my understanding is that it mainly plays the role of bass. The simplest speaker is to install a speaker on a wooden board. When the loudspeaker plays, it drives the wooden board to vibrate to form a * * * sound and amplify the bass. The design and manufacture of various speakers are inseparable from this original intention! Of course, the speaker has another function, which is to suppress high notes. Some speakers need to be lined with a layer of sound-absorbing material to better attenuate high notes! What I don't understand is that the speakers on the market are basically installed on the same speaker as the bass speaker! This is really a contradiction!

Let's get a preliminary understanding of the principle of the speaker. By the way, the sound transmission characteristics: the sound frequency that the human ear can hear is 20 to 20000 h z, and the transmission characteristics of bass and treble are different. It will be helpful to know the use of the speaker.

High notes have a strong propagation direction. Listening from the front of the speaker is completely different from listening from the back. Therefore, some speakers are made into horns, which are divided into several small squares in different directions to spread the sound more widely. Another feature of treble is that its transmission range is shorter than that of bass. Therefore, if we want to turn down the volume of high notes when we are listening to music and near the speakers, on the contrary, we can turn up the volume.

Well, I can't say that much, just a little experience and opinion, and discuss it with interested friends.

I think your clear problem is the working principle of the speaker, not the sound system. Let me answer this question briefly.

The speaker is the box of the speaker, and the problem is coming. Why put the speaker in the box when it can speak by itself? There is a direct and simple problem, that is, the electro-acoustic components of the speaker have poor mechanical characteristics, which are easy to be damaged and unsightly when used directly.

Another indirect reason is very important, that is, any speaker has a resonance peak at the lower end of the low frequency (the size of the speaker is generally between 20 and 200). The technical term in this peak manufacturer's manual is called resonance frequency. If used directly, when the low-frequency components in the audio are the same as the resonant frequency of the speaker, it will emit much louder sound. In this way, the original sound will be out of shape, and the excessive resonance sound may lead to the damage of the speaker. So be sure to put it in a carefully designed and calculated box.

The key point is to design and calculate carefully, and decompose the single resonance peak pressure of that natural frequency into a smooth small bimodal (similar to bimodal, the flatter the bimodal, the better)! However, the design and calculation of this electro-acoustic analogy is relatively complicated and the error is large. Therefore, after the design and calculation, a lot of model debugging and measurement are needed.

This answers another potential question, why can't craftsmen with high woodworking skills make good speakers? The answer is that you have no debugging equipment, no debugging theory and no debugging technology. There is no debugging site! No wonder the famous brand speakers of famous factories are tens of thousands, hundreds of thousands or even millions.

So it's so expensive that I don't even have the interest to play with speakers. Mr. Bao Jiu, a supporter of Mei School in Peking Opera, is playing the French Jinlang speaker. It's worth millions, not a person with a lot of money, so who wants to buy it? Therefore, ordinary enthusiasts have to settle for the second best. Just buy what you like and listen to what you like.

Fever is endless, as long as you like it. But this kind of good thing is very learned. If you want to have a set of high-value speakers with good quality and low price, don't be fooled by the so-called bass woodwork box produced by that woodwork factory, except for one of 1% luck, that is, 99% study!

Audio probably includes a set of power amplifier, peripheral equipment, speaker (speaker, speaker) mixer, microphone, display equipment, etc., and the principles generated in sound production are very rich. Let's follow the pace of learning and understand the principle of vocalization!