How should power amplifier and mixer match?
The literal meaning of 'matching' sometimes leads to misunderstanding. Customers often ask me, 'Can the wireless microphone I bring match your mixer '? I said that it can be matched, as long as the microphone output uses an analog output port, it can be matched. In fact, the microphones we are using now are analog outputs, and there is no problem of matching. The matching of sound system is not the same as the concept of matching computer operating system and software compatibility. If the sound system uses digital transmission, it involves the protocol problem of the digital interface. The digital interface of different protocols cannot communicate. This is a matching problem that customers understand. In terms of matching power amplifier and mixer, we should focus on 'level matching and impedance matching '. As we all know, if the level is too high, the device will cause wave distortion and even burn down the horn unit, but we seldom pay attention to the negative effect caused by the low level. If the system level is too low, the following negative effects will occur: 1. Reduce system of signal-to-noise ratio. Signal-to-noise ratio is the proportional relationship between active components and noise components in sound signals. There are two kinds of system noise, one is noise caused by heating of electronic components, the second is the ambient noise picked up when the microphone is turned on. In the same performance venue, these noises are relatively stable. How to improve the signal-to-noise ratio during the performance? If it is a music signal, try to increase the gain of the music signal (But there must be no Xiao Bo). If it is the signal of the microphone, you can't just increase the gain, increase the gain, and the ambient noise will increase. At this time, the person who needs to use the microphone should try to increase the sound volume, in order to improve the signal-to-noise ratio more effectively. How should power amplifier and mixer match? Wrong selection will affect the whole effect. Four channels 4x 1350w pure rear digital power amplifier 2. Submerged the weaker details in the music. This concept is usually ignored. It is generally believed that the gain of the mixer can be turned to the system for a certain amount of sound pressure, and there is no need to turn to the maximum distortion-free state. But if so, the details of our music will really be lost. From the principle of signal-to-noise ratio, it is not difficult for us to understand the reason for being lost. The music is recorded in the recording studio. The sound conditions of the recording studio are much better. Recording a piece of music, for example, when the volume of one of the instruments is lower than 40dB, it will be clearly picked up, when the instrument is replayed on the spot, the noise above 40dB on the spot will drown out the sound of the instrument. The noise of our performance site is basically higher than 40dB. Only by increasing the gain of the music signal as much as possible can the music signal be amplified as much as possible to achieve the purpose of increasing the signal-to-noise ratio. It can be seen that level matching is very important in the system, and both large and small levels will cause negative effects. Today, I will introduce you to a level matching experience, how to properly match the system level without knowing any device indicators. Step 1: the power amplifier input level knob is set to a minimum, and a test music is prepared to adjust the system level. It is a test music because the volume of the vocal signal is unstable and the test is inaccurate. 【 Note: music signals must be tested on the premise of impedance matching, otherwise distortion will also occur ( Impedance matching will be specifically introduced in future articles)]. Step 2: adjust the level of the player. If it is played by the CD player, there is no need to adjust it. If it is played by the computer, adjust the volume output of the computer to the maximum (0dB); Step 2: push up the pusher of the music input channel and the output bus to 0dB to increase the gain of the mixer until the bus output level shows the maximum but does not appear Xiao Bo 【 Note: There is no audience at the scene during the general test. When the audience comes into play, the sound will be absorbed and the sound pressure will not feel enough. Then, during the test, the pusher of the music channel can be less than 0dB, leaving a certain margin]; Step 3: Check the peripheral processing equipment-- Such as the equality of the equalizer, to ensure that there is no wave, if it appears, reduce the gain of the music mixer; How should power amplifier and mixer match? Wrong selection will affect the whole effect Step 4: turn on the power amplifier level knob until the required sound pressure ( Sometimes the power amplifier level knob will open very small, sometimes it may open to the head, it doesn't matter, the sound pressure is enough). Note at this time that if the power amplifier rear panel has a gain switch function, you also need to know the parameters of the power amplifier connected device, first set the gain switch, and then raise the level ( How to set the gain switch of power amplifier will be described in later articles); This level matching method, the sound will be full and many details will get a good replay effect. When the speaker does not replay the sound, the noise in the Speaker will be much smaller.