How to make bamboo tube speaker

With the improvement of speaker quality, many high-power, small-caliber, wide-band high-quality speakers have been launched, which fundamentally improves the sound effect of small-volume speakers. The bamboo tube speaker I made is based on these advantages of speakers, and is designed and made according to the principle of bamboo musical instruments. Using bamboo tubes as the box body is not only convenient to obtain materials, but also low in cost, and the tools are simple, and the production process is even simpler.

1. Power and size of the speaker I use a bamboo tube with a diameter of 152mm and a length of 348mm, and a 5-inch bass speaker with a maximum power of 100W, to design and make a pair of main speakers, which are connected to a Qisheng amplifier. The actual listening effect is no less than that of a professionally made wooden Fidec speaker. In addition, I have also designed and made small bamboo tube speakers of different styles according to different needs, such as two-channel one-piece speakers for walkmans and multimedia, and the effect is good.

2. Selection of bamboo tube and fixing of speaker I selected bamboo tube according to the diameter of speaker. You can also select the speaker according to the diameter of bamboo tube, as long as the inner diameter of the bamboo tube is equal to or greater than the diameter of the speaker. Select "U"-shaped bamboo tube (i.e. bamboo section is naturally closed at one end), and install the speaker at the other end, which is convenient for making monophonic speakers. Select "H"-shaped bamboo tube (i.e. bamboo section is in the middle), so as to make dual-channel one-piece speakers, and install the speakers at both ends of the bamboo tube, with natural isolation in the middle. When selecting "U"-shaped bamboo tube, extend 100mm beyond the bamboo section, which is used to increase the length and weight of the box. Regarding the fixing of the speaker, if the inner diameter of the bamboo tube is not much smaller than the diameter of the speaker, you can remove a layer of the inner wall of the bamboo tube until the speaker is installed. If the inner diameter of the bamboo tube is not much larger than the diameter of the speaker, use hot melt glue to fix the speaker in the bamboo tube. If the outer diameter of the bamboo tube is equal to the diameter of the speaker, it is better to fix the speaker to the top of the bamboo tube with screws.

3. The inverted phase hole and the bracket setting The inverted phase of the bamboo tube speaker is different from other speakers. According to experiments, if a hole of different sizes is opened at different positions of the bamboo tube speaker, its sound effect will change significantly. The bamboo tube speaker I made is based on this inverted phase hole. After many experiments, the position and size of the inverted phase hole are: starting from the tail of the effective box, a rectangular hole with a length equal to the bamboo tube radius and a width equal to half of the bamboo tube radius is opened, and the purpose of inverted phase can be achieved. The bracket is a tripod used to support the speaker. Take a bamboo tube with the same diameter as the speaker and 150mm shorter than the speaker, cut it into two halves, and use one half to fix it back to back to one side of the speaker. The height and angle of the bracket can be made according to needs.

4. Sound-absorbing materials and weighting of the box. To deal with the sound-absorbing materials in the speaker and the weighting of the box, sound-absorbing materials (such as sponges) are placed in the effective box, and the quantity is adjusted according to the actual hearing. The bamboo tube speaker is small in size and light in weight, so it is easy to vibrate. In addition, the speaker is located at one end of the bamboo tube, and the overall weight is unbalanced. Appropriate weighting treatment is required. The method is to pour asphalt and stone into the extension of the tail of the speaker. For the two-channel one-piece speaker, pour it into the "bottom" of the left and right speakers respectively, and the weight is determined according to the needs. After production, apply two coats of clear paint to make the surface smoother and brighter.

Because bamboo tube speakers have the above-mentioned characteristics, especially the position of the bass reflex hole, the design size and the adjustment of the sound-absorbing material, they can effectively change the sound effect. As long as these "parameters" are adjusted properly, the best effect can be achieved.

Figure 1 is a schematic diagram of a single speaker. Figure 2 is a schematic diagram of a dual-channel one-piece speaker.