[Making a Mini Subwoofer] How a Mini Subwoofer Works
How a Mini Subwoofer Does a Small Speaker
The production of speakers is very familiar to many electronic enthusiasts, and many newspapers and magazines have published related production articles, but under amateur conditions, it is necessary to produce a Active speakers are actually not an easy task, especially when you want to make a beautiful work, it is even more troublesome to find a suitable shell. The company has launched a mini subwoofer production kit, which can fulfill the dream of electronic enthusiasts in making speakers. This production uses the LM386 integrated amplifier circuit as the core component. When designing the circuit, the bass part is mainly processed to achieve heavy The effect of bass. This production kit not only trains the practical ability of the producer, but also serves as a tool for enjoying music after the completion of the work, which really kills two birds with one stone. In addition to entertaining yourself, this kit has a reasonable design and requires a moderate number of components, so it is also very suitable for electronic colleges, vocational schools, etc. as a supporting teaching material for electronic training to improve students’ hands-on ability in electronic production!
The production method of the mini subwoofer speaker
The working principle of the mini subwoofer: LM386 is an integrated power amplifier circuit, and the mains is stepped down by a transformer , After bridge rectification and capacitor filtering, a DC voltage is formed. After being stabilized by the three-terminal voltage regulator integrated circuit 7909, a stable -9V DC voltage is output as the working power supply of the whole machine. LED1 is the power indicator light, and the light will light up when the switch is turned on. After the audio signal passes through the volume potentiometer, it is input to the non-inverting input terminal of IC2. After internal amplification, the amplified audio signal is output from pin 5 to drive the speaker to sound. Pin 1 is connected to a feedback circuit. Since the feedback to the low-frequency part is small, the whole circuit has a strong amplifying ability to the low-frequency part to achieve the purpose of circuit design.
Installation and debugging
When installing the circuit, as long as it is installed according to the symbols marked on the circuit board, it can generally be successful at one time. The key is that some mechanical installations need to be paid attention to. The following is the installation The easy-to-occur problems are explained in order to avoid problems during production:
1. When installing C2, it must be installed horizontally. The installation position of each component can refer to the actual photos we made:
2. The circuit board is fixed by the volume potentiometer fixing screw. When fixing, pay attention to whether the position of the power indicator and the power switch is correct. Align the holes on the panel of the speaker box, and align the audio signal input holes with the holes on the back of the box;
3. Tie a knot before the power cord extends out of the box to prevent the cord from being pulled out ;
4. Don’t block the top holes when installing the speaker, the top holes are for fixing the panel, otherwise the panel will not be installed in place, the holes for fixing the panel
After all the components are installed, insert the audio signal cable into the speaker, and the other end into the audio signal output device, such as computer, MP3, etc., plug in the power supply, turn on the power switch, the power indicator light is on, then turn the volume potentiometer to control The volume of the sound, so that you can slowly enjoy the music with the fruits of your labor! The finished mini subwoofer.
