There are differences in the number of input channels (for example, the channels such as 6, 8, 10, 12, 24, etc.), the number of panel function keys, and the output instructions of the mixer, and even some tuning The station also has a power amplifier function. What are the main functions?
1.Signal amplification
The function of amplifying program signals, such as microphones (microphones), radios, CD players, tuners, electronic musical instruments and other different program sources. After entering the mixer, different signals require different amounts of amplification , So the mixer must be able to handle different signals separately, such as the musical signal and the human voice signal of an instrument during a performance are different in amplitude.
In order to adapt to the different levels of the input signal, the mixer usually has two sockets at the input end of the mixer, high level (line input) and low level (microphone input). The former mainly accepts recorders, CD players, and tuners. The input signal can also accept the strong signal returned from the reverberator and other devices, and the latter accepts the weak signal from the microphone and performs sufficient amplification.
2. Signal processing
The most basic signal processing is frequency equalization (that is, tuning). The input channel of the mixer is equipped with a frequency equalizer (EQ). Different signals have different timbres due to their respective frequency spectrums and harmonic components. At the same time, the effects of buildings in different places on the sound will also change in timbre. For example, we are in some closed spaces. For example, the sound of singing in the bathroom will be more reverberant than in an open place.
The tuner should enhance or attenuate the different frequencies of the sound in accordance with the requirements of the program content to beautify the timbre of the sound source. According to different sound reinforcement environments, the different sound signals entering the mixer are processed separately to make the sound as close to the original sound as possible.
For example, input audio signals from microphones, recorders, optical disc players and other equipment to the mixer for mixing and synthesis, and individually adjusting the tone of any audio channel. There are functions such as gain, treble, midrange, bass, delay, reverb, left and right size, and equalization.
Each channel of the mixer has the same processing methods, such as: 3-band equalization, gain controller, high-pass filter, etc. Setting these in the input channel can eliminate some noise in the program signal.
3. Signal mixing
Signal mixing can also be said to be the combination of signals. The input signal of the mixer often has many channels (including the signal returned by the effector), but the final signal output through the mixer may only be one or two. After adjusting the signals of each channel, the various signals should be combined into a standard left and right channel (ie stereo) and output as the input signal of the next-level equipment.
4. Signal distribution
The mixer not only has multiple inputs, but also multiple outputs. In addition to the main output, there are auxiliary outputs, group outputs, etc. Therefore, it is necessary to distribute the various signals entering the mixer to various outputs as required. This kind of signal has two uses, one is for sound room monitoring or stage return listening; the other is for excitation signal of effector.