How many parts does the input part of the mixer consist of? The input part of the mixer consists of seven parts: insertion port, amplification part, equalization part, auxiliary part, audio-visual part, attenuation part, distribution key and so on. Among these seven components, except audio-visual component and fader component, other components are different according to the type of mixer.
What sockets are there at the interface end of the input part of the mixer? What are their respective roles? There are generally three kinds of sockets in the input part of the mixer: (1) Canon socket: female three hole socket, and each end has a logo number, namely 1, 2, 3, which stands for 1, 2, 3 in turn. Two terminals are called hot ends (or high ends) and three terminals are called low ends (or low ends) for the transmission of sound signals. The 1 terminal is a grounding terminal, which is connected with the machine shell and the shielded wire. This is a balanced transmission jack, because the impedance of terminals 2 and 3 is the same as that of terminal 1, and it belongs to low impedance input Low=Z, so it has strong anti-interference and low noise, and is mostly used to connect wired microphones. On some mixers, this jack is labeled "Mic", which means microphone input jack. (2) Line input socket: This is a large three-core socket, and the input can be balanced with a large three-core plug, in which the tip is the hot end, the ring is the dead end, and the sleeve is the grounding end. The cold and hot terminations are resistors with high resistance (e.g. 360 kω), so they are high-resistance input terminals Hi-Z. Two-core plugs can also be used as unbalanced inputs, in which the tip of the core is the hot end and the sleeve is the dead end. Except for the microphone, other sound signals enter the mixer through this jack. (3) insert. (Insert): This is a large three-core socket, also called Send/Ret. This is a special socket. After pre-amplification, the sound signal entering the mixer is led out by the ground wire of the large three-core and sleeve, and then processed by other external equipment (amplification, equalization, compression, etc.). ). Then the grounding ring and sleeve of the socket will send the processed sound signal back.
Some mixers also have direct output sockets. Most mixers with this socket are live mixers. This is an output socket, which can be output from the preamplifier, parameter equalizer or fader of the mixer. Some mixers are also equipped with lotus sockets for tape signal input, which are used for signal input of the card holder (tape recorder). Only one sound source can enter each channel of the mixer. If the microphone jack is used in this channel, the line input jack will be empty, otherwise the two sound sources may interfere with each other and have mismatched impedances, resulting in sound distortion. If the switch for microphone input and line input is installed in this subpacket, it is allowed to access two audio sources, and the audio signal entering this channel through the switch is still one audio source signal. In addition, some mixers are equipped with a +48V button, which can provide working voltage (dreamland power supply) for condenser microphones. There is also a mixer with a phase inversion key. Press it to invert the input sound signal 180 degrees.
What function keys are included in the amplifier component of the mixer input channel? What do these function keys do? There are usually two function keys in the power amplifier assembly of the input channel of the mixer, namely the fixed attenuation button (Pad) and the Gain adjustment knob (GAIN). (1) fixed value attenuation key (Pad): Press it, the input signal can be attenuated by 20dB (equivalent to 10 times), and the fixed value of a few mixers can be attenuated by 30dB(32 times). (2) Gain mixer knob: adjust the amplification factor of the input signal, and the amplification range is 10~60dB. Because the signals of various sound sources entering the mixer are of different sizes, some of them are far apart. For example, the input signal amplitude of microphone is generally 150V, while the input signal amplitude of CD player is about 2 ~ 3 V. In order to make the faders of each input channel of the mixer intuitively reflect the proportion, it is necessary to make the sound signals input to the mixer basically consistent without distortion and achieve the best signal-to-noise ratio. When using these two function keys, the input signal is a big signal and must be attenuated first. When the input signal is a small signal, it is directly amplified without attenuation, so that the peak indicator light on the road is not lit. In this regard, it is very important to adjust the band, because the proportion of each instrument's sound should be intuitively reflected in the push-pull key, which requires that the signal size entering each input channel is basically the same.
Each input channel of the mixer has a peak indicator. Should the lamp stay on during tuning? Each input channel of the mixer has a Peak indicator, which should not be lit when a sound signal is input. When it is on, it means that the input sound signal is too big and distorted after entering the mixer. Once the peak indicator light is on, you must adjust the gain adjustment knob of this circuit to reduce the gain, and the peak indicator light will go out immediately. Because this lamp is installed in front of the fader, the improvement of parameter balance may also make it shine. At this time, the total gain needs to be further reduced, and the fader has no effect on the peak indicator.
When to use the +48V phantom power button? When do I use the reverse key? If the microphone used is a condenser microphone, you must press the phantom power button switch on the mixer, otherwise there will be no working voltage on the condenser microphone. In some mixers, the phantom power button switch is not installed on the socket of each input channel, but next to the mixer power switch. In this case, turning on the phantom power supply is equivalent to adding +48V voltage to all microphone sockets, and there will be no problem when the electronic microphone and the condenser microphone are mixed, because the output of the general electronic microphone has an impedance transformation transformer, which plays the role of impedance change on the one hand and isolation on the other hand, and will not damage the electronic microphone or burn out the phantom power supply on the mixer. But don't use the phantom power supply of the mixer and the +48V power supply with condenser microphone at the same time, otherwise the power supply polarity is different and it is easy to burn out the power accessories. In some cultural performances, multiple microphones are needed to pick up the same sound source. Since each microphone comes from a different manufacturer, its output wiring may be reversed. Microphone pickup signals with opposite phases will cancel each other when mixed in the mixer, which will not enhance the pickup effect, but will weaken the pickup effect. Before sound reinforcement, we should make preparations for sound reinforcement, and each input microphone should be tried. If there is the opposite situation, you must press the reverse button in one of the ways to make the pickup signals of the same sound source from each microphone have the same phase when they enter the mixer for mixing.
Each input channel of the mixer is equipped with an equalizer. What is this equalizer? What role does it play in the mixer? Each input channel of the mixer is equipped with an equalizer, which belongs to a parametric equalizer and plays the role of sound quality compensation and artistic sound processing. When the sound is unclear, opaque, not bright, not strong, not full and not thick, it can be compensated by the relevant function keys. You can also process the sound according to subjective needs and listening requirements to make it more artistic.
I hope it helps you.