1. Improper configuration of speakers and power amplifier
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. In fact, in professional occasions, the speaker can generally withstand a large signal impact of 2 times the rated power, and it can withstand a peak impact of 4 times the rated power instantaneously without problems. Therefore, it is not rare that the tweeter is burned by the power of the power amplifier because of unexpected strong impact or long-term howling of the microphone. However, if the power output of the amplifier is too large, both the treble and bass units may be damaged. If the power of the power amplifier is insufficient, resulting in clipping of the signal overload, higher harmonic components will increase sharply.
The signal that was originally a sine wave generates a large number of odd harmonics when the amplitude of the overload is close to the square wave, which greatly increases the proportion of the treble frequency component in the signal, causing the treble frequency energy in the signal to far exceed the tweeter's ability. Withstand the power. Even though the total signal power at this time has not yet reached the rated power of the speaker, the tweeter has been overloaded and caused damage. This situation is more dangerous than short-term overloading of the signal, but without clipping. When the signal is not distorted and the signal is overloaded for a short time, the power energy falls on the bass unit with higher power, which does not necessarily exceed the short-term * power of the speaker, and generally does not cause a deviation in the speaker power distribution and damage the speaker unit. Therefore, under normal conditions of use, the rated output power of the power amplifier should be 1-2 times the rated power of the speaker, in order to ensure that the power amplifier does not cause distortion at the * power of the speaker.
2. Improper equalizer debugging
The adjustment of the equalizer is also crucial. The frequency equalizer is set to compensate for various defects in the indoor sound field and the uneven frequency of the speakers. It should be debugged with an actual spectrum analyzer or with other instruments. The transmission frequency characteristics after debugging should be relatively flat within a certain range. Many tuners who do not have sound knowledge can debug at will, and even a considerable number of people raise the high-frequency and low-frequency parts of the equalizer too high, forming a "V" shape. If these frequencies are increased by more than 10dB compared to the midrange frequency (the equalizer adjustment is generally 12dB), not only the phase distortion caused by the equalizer will seriously stain the music, but also easily cause the audio tweeter. Burning, this type of situation is also the main reason for burning the speaker.
3. Improper use of crossover
Improper use of the crossover point of the input terminal during external crossover, or the unreasonable operating frequency range of the speaker is also a cause of damage to the tweeter. When using a crossover, the crossover point should be selected reasonably according to 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 burden is too heavy, it is easy to burn the tweeter.
4. Volume adjustment
Many users put the attenuator of the post-amplifier at -6dB, -10dB, that is, 70% -80% of the volume knob, or even the general position, increase the input of the front stage to achieve a suitable volume, so that the power amplifier is reserved With a margin, the speaker is safe, in fact this is 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 should be doubled, and the upper dynamic margin of the input , Will be cut in half. At this time, if there is a sudden large signal, the output will be overloaded by 6dB earlier, and a clipped waveform appears. Although the power amplifier is not overloaded, the input is a clipped waveform, the treble component is too heavy, not only the treble distortion, but also the treble unit may burn out.
5. Improper low-cut selection causes damage to the woofer
Many tuners do not pay much attention to the low-cut problem. In fact, this low-cut is a hidden danger that causes damage to the woofer *. Many woofers cannot restore some ultra-low frequencies, such as frequencies below 40 Hz, but The frequency component reduced to sound energy still exists, and it is converted into heat energy, and our horn is composed of many parts glued together. When a long-term high-power input to the horn can not convert the ultra-low frequency component signal, because The volume of the cabinet is limited, the heat dissipation is not timely, and a large amount of heat gathers. Once the glue cannot bear, it will melt, causing the elastic wave to fall off, the voice coil is scattered, and the speaker is damaged. The use of low-cut can greatly reduce the damage of the ultra-low frequency to the woofer.
6. Difference in input sensitivity when different power amplifiers are used simultaneously
In engineering, there is often a situation where different brands and models of amplifiers are mixed. There is an issue that is easily overlooked, that is, the input sensitivity of the amplifier. This problem is also often ignored, that is, the same power, different models The power amplifier may have a problem that the sensitivity voltage is not uniform, such as two power amplifiers, the output power 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 these two power amplifiers receive the same signal at the same time When the signal voltage reaches 0.775V, the output of the A amplifier reaches 300W, but the output of the B amplifier only reaches 150W. Continue to increase the signal level. When the signal strength reaches 1.0V, the A amplifier is overloaded, and the B amplifier has just reached the rated 300W Output Power. In this case, the speaker unit connected to the overload signal will be damaged. When the power amplifiers with the same power and different sensitivity voltage are mixed, the input level of the power amplifier with high sensitivity should be attenuated. It can be unified by adjusting the output level of the pre-stage equipment or reducing the input potentiometer of the amplifier with high sensitivity. For example, the two amplifiers mentioned above are both 300W output power amplifiers. The sensitivity voltage is 1.0V and the other is 0.775V. At this time, reduce the input level of the 0.775V amplifier by 3 dB or put the power discharge flat knob At the -3dB position, when the two power amplifiers input the same signal, the output power is the same.
7. The large signal momentarily disconnects causing the woofer to freeze
On KTV, in many cases, private room guests or DJs will have a very bad habit of cutting songs or muting under loud pressure. Especially when playing Di Qu, it is easy to cause the voice coil of the woofer to snap or burn. The audio signal is input to the speaker through the current mode. The speaker pushes the paper basin forward and backward by electromagnetic force to make the air vibrate into a sound. When doing a large-scale exercise, the signal input is suddenly broken, which is easy to cause the loss of recovery ability after a certain degree of movement The unit is damaged.
8. The front stage, the components of the power amplifier are self-excited
The circuit in the output section of the front stage is broken down, which results in a pure sine wave audio frequency output, similar to some frequency howling, and the output power is very large, which can directly cause the coil of the woofer to burn due to power overload. The power amplifier becomes a DC output due to current breakdown, which damages both the speaker's high and low units. The eight points summarized above are not only for KTV venues, but also for bars and scenes.