Discussion On Selection Of Transmission Cable For Sound Equipment
In the sound engineering, must use is the wire, in fact, material selection is also very important, wire difference such as signal loss, such as distortion. The signal transmission between analog digital devices in a sound equipment system must be interconnected with wire rods. No matter what format, the application of what form of system equipment, the use of wire is very critical, sometimes in a certain link to ignore the communication characteristics of cable, a variety of transmission characteristics of the use of cable and the use of different devices interconnect plug-in characteristics. Even if there is a good equipment, there is no reasonable collocation of audio cable and connector, can not play the best effect of its equipment. Therefore, according to the professional theory and the practice of many years of audio technology, audio equipment transmission cable selection.
1. Digital Audio Cable
Common digital audio cable can use the same connector as analog audio, such as Kanong XLR, Lotus Port RCA, BNC and so on. Of course, analog cable to replace the digital cable, but also can send the signal, but will affect the quality of transmission.
The output impedance and cable impedance of analog cable and digital equipment are strictly required. Analog cable No matter how long, at the point of the cable, impedance is 600, analog equipment at the level of the input output impedance of less than 600 Ω will not affect the sound quality of analog audio. If the digital audio device is different, the digital audio signal is a high frequency pulse data flow, in order to accurately transmit the signal, the cable must be matched with the sending and receiving equipment, the impedance of the end-to-end cable must be kept uniform standard
If the cable of analog equipment replaces the digital cable on the digital device, its characteristic impedance does not match, because the frequency of the digital electric signal is very high, the skin effect of the current on the wire is more deep when the characteristic impedance matches, the better the transmission effect is. Do not match runtimes skin will be lighter, transmission effect is worse, this is because most of the current in the cable formation of reflection, will generate standing wave and consumption of signal energy, so that the digital pulse signal waveform distortion. Because of the cable impedance mismatch, the distribution capacitance, the distribution inductance and the resistance can directly affect the frequency response in the signal, which affects the rise and fall along time of the pulse (that is, the code element is "1" or "0"), at the beginning and end of each data bit cycle, there is a level jump, the mismatch will affect the level of complete jump, the transmission receiver, the digital signal interpretation will appear error, if the pulse rise along time and descent along the time of the occurrence of the offset, Can cause the jitter time to be long and reduce the audio quality, even produces the noise to degrade the sound quality.
In the recording and production of various types of programs, the audio cable is needed for the audio system equipment, in addition to digital mixer, there are a lot of analog peripheral equipment such as all kinds of microphones, equalizer, delay, effect, synthesizer, D/A converter, audio processor, digital playback audio equipment, listening to speakers and other equipment, often think connected on can, ignoring program quality transmission indicators. If the equipment used in the technical indicators is not high, the lack of cable can not be revealed; if the equipment indicators in the recording room are all in the level of equipment, the application of impedance matching cable becomes an important link that can not be neglected in the audio index. This result must be used to match the transmission cable to the device, while the device input and output level should be matched reasonably (this is no longer discussed).
2, Analog audio cable
Analog audio cable can be roughly divided into microphone cable, transmission line cable and speaker cable. Audio Cable has a single core line, a two-core line, three-core line. The core line is the conductor of the audio signal, and the outer layer of the conductor is composed of a braided mesh and a protective coat covering a metal wire, shielding the external electromagnetic interference, can also be used as a signal, in the shielding layer of the outermost injection of plastic or rubber covered with non-conductive, for the inner conductor shielding line to resist tension, but also to protect the shielding layer from corrosion; the outermost layer of the outer layer protects the inner layers and makes the cable durable.
The audio cable also considers the skin effect, generally using copper wire surface silver or tin plating as a conductor, because it is low cost, good conductivity, easy to move.
Analog audio cable using a typical centralized plug form, speaker cable commonly used in large diameter multiple stranded stranded wire, and sometimes with banana plugs or other self-locking plug. When connecting plugs and sockets, be sure to keep the most tight connection. Generally speaking, Jane uses Kanong (XLR) or (RTS) 6.25-core (i.e. 1/4-inch), unbalanced multiple-use (RS) 6.25 or Lotus port (RCA) connectors. Analog and digital equipment applied on the appearance of the cable is also slightly different, careful point can be distinguished completely, in the use of principle, must not be confused or wrong use, which is the decision audio system equipment quality and work indicators, is an important audio equipment technical work.