Loudspeaker maintenance and failure analysis

For most users, there will be no special attention to the use of multimedia speakers. Many users are unfamiliar with the product structure and lack of relevant knowledge. They often make do with it after a small failure of the speaker. After changing it again, in fact, many of the fault repairs of multimedia speakers are very simple, and ordinary users can easily handle them.

As a durable consumer product, speakers are not prone to failure, but they often make you very annoyed when a problem occurs and bring us a lot of inconvenience. Taking precautions in advance, doing a good job of maintenance and maintenance during the daily use of the speakers can at least delay the time of the speakers and make your use more comfortable.

Today we will take a look at the daily maintenance methods of speakers:

The speaker is an important part of the entire audio system, and the value is about half of the entire system, so it must be treated properly.

①Avoid placing it in a place exposed to direct sunlight, not near heat radiating appliances, such as stoves, heating pipes, etc., and do not place it in a humid place.

②Before connecting the speaker to the amplifier, cut off the power of the amplifier to avoid damage to the speaker.

③The feeder connection with the amplifier should be secure, it should not fall when pulled, and the positive and negative polarity should not be connected wrongly. The feeder connecting the loudspeaker should be thick enough and not too long to avoid loss and deterioration of damping. Deviate frequency response maximum ± 0.5dB (0.75mm2 wire maximum length 9cm, 1.5mm2 wire maximum length 14m, 2.0mm2 wire maximum length 21m.

④Pay attention to whether the impedance of the speaker is suitable for the recommended value of the amplifier

⑤Do not use beyond the rated power. Otherwise, the sound quality will deteriorate and even the speakers will be damaged.

⑥The shell should be wiped with a soft, dry cotton cloth, and do not apply furniture wax, benzene or alcohol.

⑦Dust on the surface of the speaker can only be removed with a soft brush, not a vacuum cleaner.

⑧The speaker should be placed on a firm and sturdy floor to avoid bass attenuation. Do not place the speakers too close to the wall.

⑨ Do not place the speakers too close to the turntable, so as not to produce acoustic feedback and cause howling.

⑩If there is a middle and high sound level adjustment, it can be adjusted according to listening requirements to satisfy the sound reproduction.

Loudspeaker maintenance and failure analysis

Speaker system failure analysis
The speaker system is one of the important components of audio equipment, usually composed of speakers, crossovers, cabinets, sound-absorbing materials, etc. The failure rate of the speaker system is relatively low, and there are fewer types of failures. Common failures fall into the following four categories.

1. Silent

1. The speaker cable is disconnected or the frequency divider is abnormal. After the speaker wire is broken, the speaker unit has no excitation voltage, which will cause a silent failure. The frequency divider is generally not easy to break, but there may be failures such as lead connector unsoldering and short circuit of the frequency divider capacitor.

2. The voice coil is broken. Use a multimeter to measure the soldering lugs of the speaker lead wires. If the resistance is ∞, use a knife to scrape off the paint on both ends of the voice coil to expose the bare copper wire before testing. If it still doesn’t work, it means the inside of the voice coil. Broken wire; if the measurement is on and there is a "click" sound, it indicates that the voice coil lead is broken. Solder the wire end, and then another piece of enameled wire similar to the voice coil winding can be soldered.

3. The speaker wire is broken. Because the speaker cone vibrates frequently, the braided wire is easy to break, and sometimes the wire is broken, but the cotton core wire is still connected. This kind of braided wire is not easily available and can be replaced by a slightly longer flexible wire.

4. The voice coil is burnt out. Use a multimeter to measure the speaker lead in the R×1 file. If the resistance is close to 0Ω and there is no "click" sound, it means that the voice coil is burned out. Before replacing the voice coil, remove the debris in the magnetic gap first, and then carefully put the new voice coil into the magnetic gap, right the voice coil, and fix the upper and lower positions of the voice coil with super glue while listening, and wait until the voice coil is in the best position. After the position, use super glue to fill the gap between the voice coil and the paper cone to about half, and finally seal the dust cover, put the speaker cone up, and place it for a day before normal use.

2. The sound is sometimes missing

1. The speaker leads are bad. It is usually caused by mold breakage of the voice coil wire or poor welding. When the paper cone vibrates frequently, the breakpoints will be connected and disconnected from time to time, resulting in an irregular sound and no sound.

2. The lead wire of the voice coil is broken or about to be short-circuited.

3. The power amplifier output jack is in poor contact or the speaker input wire is disconnected.

3. Low volume

1. The performance of the speaker is poor, and the magnetism of the magnetic steel is reduced. The sensitivity of the speaker mainly depends on the magnetism of the permanent magnet, the quality of the paper cone and the quality of the assembly process. Ferromagnetic objects can be used to touch the magnetic steel, and the strength of the magnetic steel can be roughly estimated according to the size of the attractive force. If the magnetism is too weak, the speaker can only be replaced.

2. The magnetic core is loose. When the magnetic conductive core of the speaker is loose, it will be attracted to one side by the magnetic conductive plate, causing the voice coil to be squeezed to hinder normal sound production. When overhauling, you can lightly press the paper cone with your hands. If you can't press it, it may be that the voice coil is pressed by the stem, and you need to disassemble and re-fix it before it can be used again.

3. The frequency divider is abnormal. When there is a defective component in the frequency divider, the signal of the corresponding frequency band is blocked, and the speaker of this frequency band has a small volume failure. Should focus on checking whether the crossover capacitor in parallel with the woofer is short-circuited, and whether the crossover inductance coil in parallel with the tweeter is short-circuited between layers.

Fourth, the sound is abnormal

1. There is debris in the magnetic gap. If debris enters the magnetic gap, the voice coil will rub against the debris when vibrating, resulting in a hoarse voice.

2. Voice coil wipe core. The position of the voice coil is not correct, and it rubs against the magnetic core, causing sound distortion. Correct the position of the voice coil or replace the voice coil during maintenance.

3. The paper cone is broken. The paper cone should be replaced if the damaged area is large, and the smaller damaged area can be repaired with a thinner paper cone or other tougher paper.

4. Poor cabinet. Poor sealing of the cabinet or improper installation of the decorative net cover, etc., will cause cracking sound during playback. In addition, if the cabinet plate is too thin, it will cause resonance and abnormal sound.
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