Why does a speaker always burn a high pitch

Many audio engineers or performance engineers often encounter a problem that their boxes always burn high pitch. What's the matter?

The output power of the power amplifier is too large, which causes the damage of the high sound unit, but it is not in fact. Under professional occasions, loudspeakers can withstand 3 times greater than rated power and can withstand 5 times the peak impact of rated power without any problems. Therefore, it is not due to the accidental strong impact or the long time howling of the microphone, but the high power amplifier and the high tone unit are rare.

As we all know, there are many loudspeakers in the sound box, the power that the loudspeaker bears, and the different distribution according to the difference of the frequency division points.

The rated power of a loudspeaker is the largest pink noise power of a professional speaker. That is to say, the rated power of a loudspeaker is the power of analog signal, which is capable of being subjected to pink noise or broadband. A two frequency speaker with a frequency division point of 1.6kHz and a rated power of 100W, at a rated power, the bass unit can be allocated to the output power of 78W, while the tweeter unit is allocated to 22W only. Therefore, the 100W's pink noise power or ordinary program signal power can be applied to the loudspeaker, and when the single frequency signal of 100W is used to test, no matter the high pitch or the bass unit may be damaged. If a three - frequency sound box, the frequency division of the medium and the soprano is at 4kHz, the power of the soprano unit is only 5% of the nominal power. If the power is misallocated, it will easily cause the damage of the soprano unit.

Under normal circumstances, if the signal input to the speaker increases by 1 times, the power of the tweeter will only increase by 5W. But if the power of the power amplifier is not enough, the signal overload will appear and the higher harmonic component will increase dramatically. Originally 1kHz sinusoidal signal, square wave clipping close in overload, will be in the 1kHz sine wave, odd harmonics generated a large number of sine wave energy such as 3kHz, 5kHz, treble components in the signal ratio increased dramatically, resulting in high spectral energy signal in far more than treble power unit can bear. Even if the total power of the signal does not reach the rated power of the sound box at this time, the soprano unit has been overloaded and caused damage.

This situation is more overloaded than the signal in short time, but it is more dangerous without cutting. When the signal is not distorted, the 1kHz signal with short time overload will fall on the larger bass unit, and it will not exceed the loudspeaker's short-term maximum power. Generally, it will not cause the deviation of speaker power distribution and damage the speaker unit. Therefore, under normal working conditions, the rated output power of the power amplifier should be 2 to 3 times the rated power of the loudspeaker, so as to ensure that the power amplifier does not cause distortion when the loudspeaker's maximum power is reached.

2. Misuse of frequency divider

The improper use of the input frequency points or the unreasonable range of the working frequency of the loudspeaker is also a cause of the damage of the soprano unit. When the frequency divider is used, the frequency range of the speaker's working frequency should be strictly selected according to the range of the working frequency of the loudspeaker provided by the manufacturer. The tweeter crossover point if the choice is low, bear power burden, it is easy to burn the tweeter, so is the midrange horn.

The improper use of the input frequency points or the unreasonable range of the working frequency of the loudspeaker is also a cause of the damage of the soprano unit. When the frequency divider is used, the frequency range of the speaker's working frequency should be strictly selected according to the range of the working frequency of the loudspeaker provided by the manufacturer. The tweeter crossover point if the choice is low, bear power burden, it is easy to burn the tweeter, so is the midrange horn.

3. Improperly debugged for equalizer

The adjustment of the equalizer is also crucial. The frequency equalizer is designed to compensate the various defects of the indoor sound field and the uneven frequency of the loudspeaker, so it should be debugged with the actual spectrum analyzer or other instruments. The transmission frequency characteristics after debugging should be relatively flat in a certain range. Many of the speakers who didn't have the knowledge of sound were able to debug at will, and even a large number of people had raised the high and low frequency parts of the equalizer too high, forming the "V" shape. If the frequency and frequency is higher than 10dB compared to enhance the tenor (adjust the amount of equalizer in 12dB generally) words, not only caused the serious phase distortion equalizer to the sound of music at the same time, was also extremely easy to cause the sound tweeter burned, this kind of situation is the main reason for damage of the loudspeaker. Of course, the design of sound system according to the actual situation, considering the size of the site, such as purpose, build sound conditions, to determine the maximum continuous sound pressure level according to the actual conditions of use, and then determine the maximum value of the SPL speaker.

4. Volume regulation

Many users to post amp the attenuator in -6dB, -10dB, 80% - 70% volume knob, even the general position, by enlarging the mixer input to the appropriate volume, that the power amplifier of a room, the speaker is safe, actually this is wrong. The power amplifier is the input signal attenuation attenuation knob, if the power amplifier input attenuation of 6dB, which means to maintain the same volume, mixer or front level must be multi output 6dB voltage, 1 times higher, the dynamic margin input, commonly known as "head space" will be cut in half. At this time, if there is a sudden big signal, it will overload the output of the mixer early by 6dB and appear the wave of the clipping. Although the power amplifier has not been overloaded, the input is the clipping waveform, the high pitch component is too heavy, not only the high sound distortion, but also the soprano unit may burn out.

The above analysis

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