What Are the Different Types of Stereo Sound Systems?

Sound system refers to the use of a microphone to convert the sound wave signal of the original sound field into an electrical signal, and the electrical signal is processed by some electronic equipment according to certain requirements. Finally, the electrical signal is converted into a sound wave signal by a speaker for playback. The entire system from microphone to speaker is the sound system. Among them, the microphone and the speaker are called transducers. Although the electrical signals in the sound system are different in form and dimension of energy from the acoustic signals of sound waves, as signals, the nature of the information between them is consistent, that is, their amplitudes have a corresponding relationship of relative magnitudes, and their The frequency is also corresponding, so the electrical signal in the sound system is in the sound frequency range of 20Hz ~ 20kHz, which is called audio signal. Audio signal, which is an important feature of the audio system.

sound system

Although there are different sound systems according to different requirements and tasks and different occasions, and there are also large differences in the size and size of the functions of the same type of sound system, there are also common structural design of the sound system The law. The composition of professional audio systems is generally centered on the mixer and grasps the ins and outs of the sound signal. The so-called ins and outs is the connection from the program source equipment to the mixer, and the so-called insult is the main output of the mixer Back-end equipment, depending on the system, either to the recording equipment or to the sound reinforcement equipment. In addition, according to different needs, the mixer is equipped with audio processing equipment. For home audio systems, the center of the pre-amplifier (pre-amplifier) is seized for matching.

Of course, the above system does not refer to sound reinforcement (although sound reinforcement is also included), because from Edison invented the gramophone more than 100 years ago to the rapid development of sound technology today, the sound recording and playback that allows sound to cross time and space barriers Sound systems have always been the first task to be completed, so sound systems can be divided into two types of sound production (recording) and playback.

It should be said that there is a sound transmission link between the production and playback of sound. The sound transmission includes the sound recorded on a certain carrier (such as a magnetic tape or a CD record) or sent by broadcast radio waves, but this Does not belong to the category of audio system, because the former is not a system composed of electronic equipment, the latter is not an audio signal system.

Whether it is sound production or playback, there is another important task, that is, sound processing, because sound production and playback cannot mechanically reproduce the original sound, not only to eliminate the ills of the original sound, but also to a certain aesthetic It is required to beautify the sound quality, and even to create a sound that was originally not available, which is also the responsibility of the audio system.

According to different requirements and tasks and different occasions, there are different sound systems, which can be divided from different angles, and divided into a large range of professional sound systems and home audio systems. Professional audio systems can be divided into production systems and playback systems. Production systems include music recording production systems and film and television recording production systems. No matter which production system is sometimes divided into pre-recording systems and post-production systems, in addition to broadcast production ( Real-time or recording) system; playback systems include theater, stadiums, venues, conference hall (room) PA system, song and dance hall, disco, karaoke sound system, etc. Home audio systems can be divided into music playback systems and AV playback systems; AV playback systems include home theater surround systems and karaoke systems.

It should be explained that the above production and playback system is not absolutely separable. There are also playback functions in the production system, such as the monitoring part, and there are also requirements and means for recording production in the playback system, such as live recording. Dividing in this way only emphasizes the emphasis of the system.

First, the design of the sound system The hall sound is mainly natural sound, which requires good diffusivity, uniform sound field distribution, appropriate loudness, and good naturalness. After the hall is built, a sound system needs to be installed. The purpose of using the sound system is to improve the evenness of the loudness and sound field distribution, improve the sound quality of the hall, and improve the sound effect ^[1]

Inrush current: An audio equipment is composed of resistors, capacitors, inductors, transformers and other components. They are all cold before starting up. When starting up, its resistance is small, so the instantaneous current is very large, which is 2.5-3.5 times the normal working current. This current is called inrush current and it can cause damage to the circuit. It is generated at the moment of turning on or off, and is not damaged during normal working conditions.

Back-peak voltage: Inductive components, transformers, and other units have a characteristic that when a voltage is added to or removed from a circuit, the unit generates a back-EMF to prevent this voltage from changing. Then when a voltage is applied to the inductive element when it is turned on, it generates a back electromotive force to prevent the establishment of this voltage, but the energy source of the power supply voltage is constantly flowing, so this back electromotive force only acts as a voltage damping and has little effect on the circuit. However, the situation is different when shutting down. When shutting down, a back EMF is generated in the circuit without any obstruction. This voltage is the reverse peak voltage, which is 9 times the normal voltage. Although its current is small, the voltage is very high, causing an impact on the device. Therefore, the inrush current and back-peak voltage of each audio unit are applied to the audio equipment at the same time, causing a large impact, which is easy to cause damage to the equipment. For this reason, each audio unit is preferably turned on and off sequentially one by one. The correct boot sequence is to boot in the direction of the source signal flow: turn on the deck, CD player, LD player or VCD player, tuner, equalizer, and finally power amplifier.

The correct shutdown sequence is to turn off the amplifier before turning off other equipment.

At present, in order to facilitate the use, a delayed power plug board has been invented abroad. The first group of sockets is a direct switch socket; the second group of sockets can be delayed for 1s (seconds) before the power is turned on when the machine is turned on; the third group of sockets can be extended when the machine is turned on. The power is turned on at 2s (seconds); the fourth group of sockets can be delayed for 3s before the power is turned on when this machine is turned on. This is similar when shutting down, and it also shuts down the power at different times. ^[3]