Methods to Reduce the Noise Interference of Audio Cables
Microphone cables and audio signal cables are very sensitive to interference from electromagnetic fields because of the low level of these signal sources. During the signal transmission process, some unwanted interference signals will be picked up, which will affect the sound quality. For example, after passing near a fluctuating magnetic field (such as an AC power lead), a noise signal will be induced, and a humming sound will be heard in the speaker. Measures to reduce interference signals mainly include:
1. Increase the shielding layer
Usually, the central part of the audio cable is a wire (usually copper wire is used), the outer part of the wire is covered with non-conductive plastic or rubber, and the outer part is a shielding layer composed of conductors to isolate external interference signals (sometimes also as the signal ground).
2. Using balanced cable
Adding a shielding layer can isolate most of the external noise interference, but it is not foolproof. Balanced transmission is a very widely used audio signal transmission method, which uses the principle of phase cancellation to minimize the interference suffered during the audio signal transmission process. Balanced transmission is a transmission method that combines the original signal and the replica signal into one by transmitting a replica signal in the same cable that is out of phase with the original signal, and then inverting the replica signal. The two wires are twisted together to ensure that any noise encountered along the way is picked up evenly by both cables, and it also contributes to the overall stability of the cable. At the input of the second device, the inverted replica signal on the negative side is inverted back to the positive side of the original, and the noise present in the original two signals is 180 degrees out of phase. After the superposition, the noise is removed due to the opposite phase, and the original signal is kept pure. The balanced cable uses 3 wires, which are the hot end wire (Hot, which transmits the original signal), the cold end wire (Cold, which transmits a replica signal that is out of phase with the original signal), and the ground wire (Gnd).
3. Use 4-core stranded wire
The 4-core stranded wire is named after its double-balanced pair structure, which minimizes the annular electromagnetic interference area of the cable and greatly reduces the noise caused by the electromagnetic induction of adjacent cables. The double-balanced pair line adopts 5 lines, which are 2 hot end lines, 2 cold end lines and 1 ground line, of which 2 hot end lines and 2 cold end lines need to be crossed and cannot be arranged adjacently.
Welcome to contact us for Audio Cables: https://www.pcm-cable.com/audio-cables/
