1. What is the withstand power of speakers?
As the name implies, the power of the speaker means "the input speaker will not be damaged if it does not exceed the marked power, and it will be able to withstand it."
There are several ways to express the power of a speaker, which can easily cause misunderstandings by users, and cause damage to the speaker due to improper use. Some of the speaker parameters are marked with rated power, that is, long-term power, which means that it will not be damaged under this power state for long-term use.
The factory tested the rated power at a constant temperature of 20°C, using pink noise signals for 48 hours of continuous work. The use environment in the KTV private room is relatively harsh, and the music contains many large dynamic peak signals. It is recommended that the input power is lower than the rated power by more than 20% to use the speaker, which will be much safer.
The speaker's ability to withstand peak power is conditionally limited. The time setting is 1 second, and it can only be repeated 10 times. If it exceeds it, it may be damaged. The speakers with peak power should be used with special care. It is recommended that the power does not exceed the peak power. 1/4 of power.
2. What is the rated output power of the amplifier?
The rated output power of the power amplifier refers to: "the long-term output power under the condition of no distortion (generally the output distortion does not exceed 1%)". In this state, the power amplifier is safe and reliable. In fact, there are several prerequisites: one is that the mains voltage is required to be the standard 220V. If the mains fluctuates, the output power of the power amplifier will also change; the other is that there are impedance requirements for the load (speaker), such as 2 *150W (8Ω) power amplifier, in the case of 4Ω load, the output power may reach about 230W; the ambient temperature of the third factory during the power amplifier output power test is 20 ℃, if it is used in a KTV private room, if the heat dissipation is not good , Even if it is working under rated power conditions, it may damage the power amplifier; the rated power of its four-power amplifier refers to the undistorted output power, not that the power amplifier can only output this power, if the power distortion is allowed to increase the output (increase Large volume knob), the output distortion power is very large, far exceeding the rated power. For example, when a 150W (8Ω) power amplifier is not distorted, the larger output voltage should be less than 35V (power=voltage2/resistance). When distorted, the output voltage may rise to 40V, and the distortion power at this time will reach 402/ 8=200W.
3. How to match the power when choosing power amplifier and speakers?
When selecting power amplifiers and speakers, we suggest that the rated power of the power amplifier should be slightly greater than the rated power of the speaker, generally 20-30% is appropriate, and at least the same should be the same. The rated power of the power amplifier must not be less than the rated power of the speaker, forming a "small horse cart". A small horse-drawn cart will cause the entire system to perform softly and weakly, and the dynamic and music performance levels will deteriorate. If the user increases the bass tone knob or the volume knob too much in this case, the output will be distorted, that is, the internal output will be distorted. Pedestrians often say "clipping", resulting in direct current output (under normal circumstances, the output waveform of the power amplifier is an alternating current sine wave, and after distortion, it will "clipping" to form an approximate direct current). In the case of DC output, the power amplifier can no longer control the speaker, so it will burn. When the power of the power amplifier is greater than the power of the speaker, it is necessary to control the output of the power amplifier not to be too large, so as to ensure that the power amplifier has enough "power reserve", has good dynamic performance, and will not damage the speaker.
4. Why do you often "burn the tweeter"?
The tweeter is the weakest link in the speaker. When the speaker is damaged, the tweeter is often the first to be damaged. Of course, improper use will also burn the woofer. When designing speakers, factories generally retain a certain margin under the precondition of rated power. After we visited a large number of users, we found that most of the "burning speakers" were caused by improper use, mainly in the following aspects :
1) Improper matching of speaker and amplifier power.
Some customers choose a 2*200W (8Ω) power amplifier to match the CS-450A speaker with a rated power of 120W, and the impedance of the speaker is 6Ω. When the power is placed in a 6Ω load, the full power output without distortion has reached about 250W. The actual power allocated to each tweeter is 25W, which has exceeded the rated power of the tweeter, causing damage to the tweeter. Customers can measure the actual output power of the amplifier by themselves: correctly connect the amplifier to the speaker, turn on the loudspeaker volume knob, measure the voltage at the output of the amplifier with a multimeter (the needle will swing, take a larger value), and then use the measured voltage The square value of the value is divided by the impedance value of the speaker to get the output power of the amplifier at this time. Interference, but when using it, the mouth must face the microphone and be closer, generally a distance of 2 to 100px is appropriate, if it is too far away, or not directly, it will cause "not enough input", especially bass loss It will be big. The average entertainer may not have this "professional knowledge", knowing that he has used it improperly and complaining that he is tired of singing. To solve these problems, we must teach our waiters to help the guests, but the method must be proper, and the guests must not be blamed. It is better to hang a reminder on the wall to use the microphone correctly.
2) Improper opening and closing operations.
In some karaoke establishments, the waiter turns on the power amplifier first (and the volume knob is turned on very large) before turning on the audio source (VOD or DVD) during the power-on and power-off operation. When turning off, the audio source is turned off and then the power amplifier is turned off, and some are turned on when the power amplifier is turned off. Insert the microphone cable into the power amplifier first, and then insert the switched-on microphone into the connected XLR head. As a result, a strong inrush current is caused. The horn emits a strong bang in an instant. Due to this momentary impact, it is completely possible to damage the speaker. The correct operation method is: turn on the sound source first and then turn on the power amplifier when turning on the machine, turn off the power amplifier first and then turn off the sound source when shutting down. When inserting the microphone into the power amplifier, make sure that the microphone is connected to the line and the microphone switch is in the off state.
3) Connection failure.
Connection failure is also the culprit of "speaker burning". If the signal wire from the sound source to the amplifier is broken (sometimes the ground wire is in poor contact, it will be switched on and off), it will cause the successful amplifier to produce "high frequency self-excitation", and lightly burn the speaker. , Retest the burn-in power amplifier. Sometimes the microphone cable and the microphone are not in good contact (mostly the XLR head is loose), or the microphone skewer is not in contact with the power amplifier, or the microphone is disconnected from the ground wire (single-core wire broken shielding network) will cause a strong impact, and the speaker appears very strong. The "card..." card bursts, and the speaker will be damaged in an instant. Many users make mistakes in the microphone cable, causing the microphone to "float". This will not only cause a lot of noise in the system, but also If the speaker is damaged, the correct way is to connect the red wire to the "2" of the XLR head, the white wire to the "3" of the XLR head, and the shielded wire to the "1" of the XLR head, 6.35 skewer The red wire is connected to the core, the white wire and the shielded wire are connected to the shell. If it is a single-core shielded wire, the core wire is connected to the "2" of the XLR head, and the shielded wire is connected to the "1" of the XLR head. "3" and "1" are connected.