Summary of the reasons for the burnout of eight kinds of speakers.Audio brand bar

　　The burnout of the speakers is a very headache for our audio maintenance staff, whether it is in KTV places, bars or live. In order to let the majority of peers and friends try to avoid the burnout of the speakers in the future, we have specially summarized some common eight reasons for the burnout of the speakers (although we have pushed related articles before, and this article has been further improved). Your future work will help

　　Summary of common reasons for speaker burnout

　　1. Unreasonable configuration of speakers and power amplifiers

　　Many people who play professional audio will think that the output power of the power amplifier is too large, which is the cause of damage to the tweeter. Actually not, in professional occasions, the loudspeaker can generally withstand the large signal shock of 2 times the rated power, and can withstand the peak shock of 4 times the rated power instantaneously without any problem. Therefore, it is very rare that the tweeter is burned by the high power of the power amplifier, not due to unexpected strong impact or long-term howling of the microphone. However, if the power output of the power amplifier is too large, both the tweeter and the woofer may be damaged. If the power of the power amplifier is insufficient, the signal is overloaded and clipped, and the high-order harmonic content will increase sharply.

　　The original sine wave signal, when the overload clipping is close to the square wave, produces a large number of odd harmonics, which greatly increases the proportion of high frequency components in the signal, resulting in the high frequency energy in the signal far exceeding the tweeter unit. withstand power. Even if the total signal power at this time has not reached the rated power of the speaker, the tweeter has been overloaded and damaged. This situation is more dangerous than short-term overloading of the signal without clipping. When the signal is not distorted, the power energy of the short-term overloaded signal falls on the woofer with higher power, which does not necessarily exceed the short-term maximum power of the speaker, and generally does not cause the deviation of the power distribution of the speaker to damage the speaker unit. Therefore, under normal use conditions, the rated output power of the power amplifier should be 1-2 times the rated power of the speaker, so as to ensure that the power amplifier does not cause distortion when the speaker's maximum power is used.

　　2. Improper use of frequency division

　　Improper use of the crossover point at the input end when the external crossover is used, or the unreasonable operating frequency range of the speaker is also a cause of damage to the tweeter. When using the frequency divider, the frequency division point should be reasonably selected in strict accordance with the operating frequency range of the speaker provided by the audio manufacturer. If the crossover point of the tweeter is selected to be low and the power load is too heavy, it is easy to burn the tweeter.

　　3. Improper adjustment of the equalizer

　　The adjustment of the equalizer is also crucial. The frequency equalizer is set up to compensate the various defects of the indoor sound field and the uneven frequencies of the speakers. It should be debugged with an actual spectrum analyzer or other instruments. The transmission frequency characteristic after debugging should be relatively flat within a certain range. Many tuners without sound knowledge arbitrarily debug, and there are even quite a few people who raise the high and low frequency parts of the equalizer too high to form a "V" shape. If these frequencies are increased by more than 10dB compared with the midrange frequency (the adjustment amount of the equalizer is generally 12dB), not only the phase distortion caused by the equalizer will seriously color the music sound, but also it is easy to cause the sound tweeter. Burnout, this type of situation is also the main reason for burning speakers.

　　4. Volume adjustment

　　Many users put the attenuator of the power amplifier at -6dB, -10dB, that is, 70%-80% of the volume knob, or even in the general position, and increase the input of the pre-amp to achieve a suitable volume, so that the power amplifier is left as a With headroom, the speakers are safe, which is actually wrong. The attenuation knob of the power amplifier attenuates the input signal. If the input of the power amplifier is attenuated by 6dB, it means that to maintain the same volume, the front stage must output 6dB more, the voltage must be doubled, and the upper dynamic headroom of the input , will be cut in half. At this time, if there is a sudden large signal, the output will be overloaded 6dB earlier, and a clipped waveform will appear. Although the power amplifier is not overloaded, but the input is clipped waveform, the treble component is too heavy, not only the treble is distorted, but the tweeter may also burn out.

　　5. Improper selection of low-cut causes damage to the woofer

　　Many tuners don't pay much attention to the low-cut problem. In fact, this low-cut is a hidden danger of causing damage to the woofer. Many woofers cannot restore some ultra-low frequencies well, such as frequencies below 40 Hz. However, they cannot The frequency component restored to sound energy still exists, it is converted into heat energy, and our speakers are glued together by many parts. The volume of the box is limited, the heat dissipation is not timely, and a large amount of heat accumulates. Once the glue cannot withstand it, it will melt, causing the elastic wave to fall off, the voice coil to be scattered, and the speaker to be damaged. The use of low-cut can greatly reduce the damage of ultra-low frequency to the woofer.

　　6. Differences in input sensitivity when different power amplifiers are used at the same time:

　　In engineering, there is often such a situation that different brands and models of power amplifiers are mixed. There is a problem that is easy to be ignored, that is, the problem of input sensitivity of power amplifiers. This problem is also often ignored, that is, the same power, different models There may be a problem that the sensitivity and voltage of the two power amplifiers are not uniform. For example, the output power of the two power amplifiers is 300 watts, the input sensitivity of the A power amplifier is 0.775V, and the input sensitivity of the B power amplifier is 1.0V, then if the two power amplifiers accept the same signal at the same time , when the signal voltage reaches 0.775V, AThe output of the power amplifier reaches 300W, but the output of the power amplifier B only reaches 150W, and the signal level continues to increase. When the signal strength reaches 1.0V, the power amplifier A is overloaded, and the power amplifier B has just reached the rated output power of 300W.

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