How to make a speaker box?

If you want to sit at home and enjoy beautiful music, you must have the most basic audio equipment. So how to make a speaker box? For example, if you have a cassette recorder or CD player as the signal source, an audio power amplifier and a pair of speakers, as well as audio signal lines and speaker cables, you can form the most basic audio equipment. In the audio equipment, there are CD players and power amplifiers with complex structures, as well as speakers without complicated structures. But in the audio equipment, the most personality, the greatest impact on the playback of music, is the seemingly simple speaker box.

For music lovers who are not well-off and want to get fun and knowledge from their own hands, the most convenient self-made audio equipment is speaker box. As long as you know some regular things in the design and production of speaker boxes, you can make a pair of speaker box that satisfy your own needs.

Materials for making a loudspeaker box

Steps of making a sound box

Then choose the size of the loudspeaker box and the splitter according to the size of the loudspeaker box

Materials needed to make a speaker box

1. Speaker unit

2. Frequency divider

3. Phase-inverted tube

4. Medium and high density board and skeleton wood

5. Sound absorbing cotton

6. White latex

7. Screw

8. Junction box and terminal

9. Speaker cable

10. Speaker pad

Wood veneer or paint is required

Tools needed

1. Plate cutting tools such as circular saw, curve saw

2. Tapper, such as aircraft tapper, fixed tapper

3. Screw driver

4. Electric soldering iron and solder wire

5. Lacquer brush

A scraper may also be required for veneering

Production process of self-made speaker

Select the loudspeaker unit

Loudspeaker unit, commonly known as loudspeaker, is the key part of sound box. Only with the help of loudspeaker unit, people can convert the audio signal from CD machine and power amplifier into audible sound signal.

Speaker units are generally divided into three categories: treble, midrange and bass. Basically, it belongs to the scope of their respective duties. For the production of fine small caliber subwoofer, they can generally take into account the role of the midrange speaker; and for a high-end unit with excellent design and enough power to bear, it can also take into account the role of part of the midrange speaker. Therefore, in the small bookshelf type or floor type speaker box, it is very common to use only one high and two low speaker units. The following is a specific talk about the selection of the speaker unit.

1. How to select treble

The tweeter, as the name suggests, is a loudspeaker unit for reproducing high-frequency sound. The structure of the treble unit mainly includes horn type, cone basin type, ball top type and aluminum belt type.

Because of its strong directivity, the horn type tweeter can hear powerful treble in the front of the horn. It is mostly used for high-power sound reinforcement, conference speakers and a small number of monitoring speakers.

There are aluminum alloy, titanium alloy, titanium alloy composite film, glass film, diamond film and so on. Hard ball top treble unit repeats the treble, the timbre is bright, has the metallic feeling. Suitable for playing pop music, movie music and effect music. Excellent aluminum alloy film, titanium alloy composite film dome treble, can also better performance of classical music and voice.

There are several kinds of diaphragm materials for soft top treble, such as silk film, silk film, rubber film and bulletproof cloth film. When the soft ball top treble unit replays the music, it is dexterous, relaxed and has a good natural expression. In the performance of classical music, vocal music and other music with the concept of standard listening, it is particularly handy. It is an ideal choice for manufacturing medium and high-grade household speakers and small monitoring speakers. Especially in recent years, the upper limit frequency of rebroadcasting on silk and silk film has reached 40000 Hz. Theoretically speaking, the upper limit frequency of the tweeter should be at least 20000 Hz, the higher the better. But the high frequency upper limit excellent unit, its price also wants to be expensive.

The ball top tweeter is playing music. When playing music, the horizontal radiation angle is smaller, but the timbre is pure and the power is larger. Just because of its structural factors, it is not easy to make its upper limit frequency high enough and power large enough, so it is not easy to popularize it.

The top grade aluminum ribbon tweeter has a maximum frequency of over 30000hz and a power capacity of more than 150W. If you are a classical music lover and have strict requirements on the timbre, you may as well choose a soft ball top tweeter such as silk film.

If your speaker needs to consider both karaoke and movies in use, it's better to choose a hard top unit. Of course, this is not absolute, because the sound reproduction of the speaker is not only related to the selected unit, but also related to the design of the frequency divider and the production of the box.

 

2. The structure of the midrange unit

Generally speaking, there are only two kinds of midrange units: cone and dome. It's just that it's bigger in size and power than the treble unit, and it's more suitable for playing audio. The diaphragm of the middle tone unit is mainly composed of soft materials such as paper basin and silk film, and occasionally a small amount of alloy ball top diaphragm.

3. How to choose woofer unit

The structure of bass unit is mostly cone basin type, and a few are flat plate type.

There are many kinds of diaphragm for bass unit, including aluminum alloy diaphragm, aluminum magnesium alloy diaphragm, ceramic diaphragm, carbon fiber diaphragm, bulletproof cloth diaphragm, glass fiber diaphragm, propylene diaphragm, paper diaphragm, etc.

The paper diaphragm is also known as loudspeaker paper basin. Paper diaphragm can be divided into paper basin, press paper basin, paper based wool basin, reinforced paper basin and so on. Generally speaking, the bass unit with aluminum alloy and aluminum magnesium alloy diaphragm has a smaller diameter and larger bearing power, while the bass unit with reinforced paper basin and glass fiber diaphragm has accurate timbre and good overall flat density.

When selecting the loudspeaker unit, the bearing power of the treble unit is generally no less than one tenth of that of the bass unit; if the speaker is made of two frequency division and two unit, the bearing power of the tweeter is still higher.

In the production of three frequency speaker, the power of the midrange unit can only reach one third of that of the bass speaker.

When selecting the loudspeaker unit, it is better to choose the same impedance. The common low impedance loudspeaker units are generally divided into 4 Ω and 8 Ω. In general, the sensitivity of 86dbm should be selected for the same level. The speaker with less than 84dB is called low sensitivity speaker, and that higher than 90dB is called high sensitivity speaker.

Of course, the lower limit frequency of the treble unit is lower than 2KHz, and the upper limit frequency of the bass unit is higher than 4kHz, which will bring a lot of convenience to adjust the speaker.

Selection and manufacture of frequency divider

When you have selected the speaker unit, then it is necessary to select and make a frequency divider. Frequency divider is divided into two categories: ordinary frequency divider and electronic frequency divider.

Electronic frequency divider is to transmit the small audio signal from the signal source directly into the electronic frequency divider. The full band (from bass to treble) signals are divided into treble and bass signals by electronic frequency division, which are respectively transmitted to the corresponding power amplifier for amplification, and then the corresponding loudspeaker unit is pushed to emit sound, as shown in Figure 1. Electronic frequency division is a relatively complex music replay system, but it has good replay effect. In addition to the frequency divider, an audio power amplifier with four channels is needed in the electronic frequency division system. Electronic three frequency division system needs six channel power amplifier, while electronic four frequency division needs eight independent channel power amplifier. The advantages of electronic frequency division are good reproduction tone, easy adjustment of balance between different frequency bands, but high production cost.

Speaker box processing

In the production process of the speaker, the processing of the speaker box is a crucial link.

In the box processing, the most important only two points, one is the box processing size accuracy to be high; the other is the box material selection is accurate. Among the materials used to make speakers, there are high-grade logs, high-strength multilayer boards, synthetic materials, plexiglass and stone materials. The so-called high-grade log, not only refers to the wood itself high-grade, precious, the most important thing is that the wood itself has to go through many years of drying and aging treatment. Only in this way can we ensure that the box is not cracked and deformed.

After many years of practice, the materials used to make speaker box are multilayer boards with sufficient thickness and high-grade logs. The timbre is the best, but the price is also the most expensive. The overall feeling of plexiglass box is also good; medium density board is the most affordable material for speaker box.

In the processing of the speaker box, there are several methods as follows:

The bending method is shown in Fig. 4. This method is to make a sound box by opening V-shaped groove on the calculated long medium density board pasted with PVC fabric, then bending and gluing. This method is often used in large-scale speaker production.

See Fig. 5 for the method of inlay reinforcement. In the self-made speaker, the sheet material is cut according to the drawing, and then the glued wood strip is added at the interface of the board for reinforcement. This method is suitable for making speaker by hand.

The assembly method is shown in Figure 6. This is a new technology of speaker making. There are 45 ° and 90 ° inclined planes and notches around the speaker board with precision machining machine. When the speaker box is made by hand, the sound box with high machining precision, strong and beautiful appearance can be obtained through the self positioning effect of 90 ° notch of sound box plate and the long inclined plane of 45 ° as long as enough adhesive is applied at the interface, and the rope is used for fastening after assembly.

After the sound box is finished, as long as the surface of the box is painted and pasted with wood veneer, it will be finished.

Assembly and debugging of self-made speaker

In the final assembly and debugging of self-made speaker, the following problems need to be paid attention to:

First, the connection between frequency divider and loudspeaker unit +, - must not be connected wrong. If the connection is wrong, the sound of the speaker can't be adjusted properly.

Second, when installing the speaker unit, the tightness of each fixing screw should be consistent. Otherwise, when the speaker works, it is easy to produce unexpected resonance.

Third, the length of the inverted phase tube and the number of sound-absorbing materials in the box should be appropriate, otherwise it will affect the performance of the replayed music. In particular, the length of the inverter has a direct impact on the low end of the test frequency response of the speaker.

Through our hard work, we can not only harvest the speaker, but also increase the talent in speaker production. We can save part of the money to buy the finished speaker and use it for other purposes. Therefore, it is a good thing with multiple benefits. That is the method of how to make a speaker box!