What are the components of a set of equipment included in the stage sound? Let Xiaobian bring everyone to understand the composition of the peripheral equipment of the professional audio sound reinforcement system.
I. Equalizer (EQ): The equalizer is divided into an active equalizer and a passive equalizer. The general passive equalizer is taken as an example.
The room equalizer is a band-passing device that is used to adjust and improve the frequency transmission characteristics of the hall. It is characterized in that only the attenuation is not improved. The chopper is a third-order narrow-bandpass chopper with an attenuation of 18 dB per octave. There are also a nine-band equalizer with octave, a 15-band equalizer with 1/2 octave, and a 1/3-band equalizer. The general attenuation is 10dB, 12dB, 15dB, and 18dB.
Second, Compressor (Limiter): It is the general term for compressor and limiter
1. Compressor: It is actually an automatic volume control. When the input signal exceeds a predetermined level called a threshold, the gain of the compressor drops and the signal is attenuated. In order to increase the level of the compressor by 1 dB, the number of decibels required to increase the input signal is called the compression ratio or the compression ratio of the compression curve. For a 4:1 ratio, the input signal is increased by 8dB and its output is increased by 2dB. Since the loudness of the tone signal is varied, it is "" a certain moment may exceed the threshold level and then fall below the threshold level. Therefore, after the signal exceeds the threshold level, the compressor reduces the gain. After the input signal falls below the threshold level, the compressor recovery gain folding speed must be determined. This signal depends on the time of signal increase and the recovery time.
2. Limiter: If the compression ratio is large enough, the compressor becomes a limiter. The limiter is used to prevent the peak value of the signal from exceeding a certain level in order to avoid overloading the amplifier, tape or record. In the extreme case, the compressor is a limiter that cuts off the top of any waveform that exceeds the threshold level. Most limiters have a ratio of 10:1 or 20:1, and they can be used up to a ratio of up to 100:1. Limiters are mostly used in recording applications because for many consecutive peak signals, the threshold must be increased and manual gain reduction is used to limit those occasional extreme peak signals.
3. Dilator: An expander is a special amplifier whose gain varies with the input level. It has an extended threshold, and the sound signal below this threshold is boosted. The process of reducing the signal gain when the signal level is lowered, or increasing the signal gain when the signal level is raised, or both, is called "expansion", that is, when the signal level is low (under the extended threshold) When the gain is low, the program sound is attenuated. When the signal level increases above the threshold, the gain increases. The expander increases the dynamic range of the program tone by making the strong signal louder and the weaker signal weaker. The expander can also be used as a noise reducer such that the noise to be removed is below a predetermined threshold point and the desired signal is above the threshold point.
4. Noise reducer (NR): Signal-to-noise ratio (S/N) is an important indicator of the sound system. In the whole sound system, the tape recorder has the worst signal-to-noise ratio index, because the tape itself and the recording bias will be the same. Bring noise. The consequence of the reduced signal-to-noise ratio is that the dynamic range of the sound system is reduced.
5. Exciter: The function of the exciter: In the sound system, there are many devices, each device has a certain degree of distortion. When the sound is released from the speaker, it has lost a lot of components, mainly The intermediate frequency and high frequency rich harmonics sound like lack of presence, lack of penetrating power, lack of delicateness, lack of clarity, and lack of high frequency overtones. The exciter re-reproduces a lost device from the principles of modern electronic technology and psychoacoustics, recreating a device whose structure has two parts: one part goes directly to the output amplifier without any processing, and the other part goes through a special enhanced line. Produces a rich and adjustable musical harmonic (overtone) that is mixed with the direct signal in the output amplification circuit.
6. Delay: Its function is to spread the sound in the sound field including three components: direct sound, near-reflective sound and reverberation sound, and the delay device is a device that delays the main sound for a certain period of time before being sent to the sound field. It can produce chorus, chrome, echo and ringing effects.
7. Mixer: In the dance hall sound system, a very important part is the reverberation treatment of the human voice. After the reverberation process, the human voice can produce an electronic sound aesthetic, making the song unique. A sense of charm. It can also cover up some of the flaws in the voices of some amateur singers, making the sound less audible, turning the original song into a turbid electronic sound, just like singing a good man in the bathroom, the reverberation is very strong. In addition, the reverberation sound also compensates for the phenomenon that the amateur singer is not rich in overtones due to the lack of special vocal training.
Eight, electronic crossover: the working principle of the frequency divider: the frequency divider is to separate the audio input signal through the high, low pass filter and band pass filter to separate the bass, midrange and treble (or super high) signals, respectively Power amplifiers that are fed into each frequency band, whose output signals drive the bass, midrange, and tweeters, respectively, improve the quality of the sound.
9. Noise Gate: The noise gate is actually an electronic gate whose threshold can be adjusted. When the input signal level of the circuit exceeds the threshold, the circuit is turned on. Its characteristics are as follows: 1) The circuit starts fast, some of the tonal characteristics of the tone are quickly established, and the steady state is entered, so the circuit is more sensitive and does not make The tone produces distortion of the starting characteristics. 2) There is a delay when closing the door, there is a natural attenuation when the sound is closed, giving a comfortable feeling. The noise door is activated quickly, and the control start time button is also available, and the decay time is also controllable and adjustable.
X. Sound effect processor: The reverberator and retarder are installed on the mixer to make the sound thicker, increase the fullness, space and elasticity. At present, there are two types of effects used in dance halls, one is a Japanese-style effect, and the other is an European-American effect.
XI. Transcoder: The transposition is to raise and lower the music frequency in music through electronic circuits.
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