Delivered using a configuration of dual wires, balanced audio eliminates interference because each wire has the opposite charge, cancelling out noise. Both wires must have matching power levels and voltage and have two signal conductors. They are not shielded on the outside. Wires in audio systems are distinguished by their color, and will usually be red and black, but the color scheme can vary according to the device or manufacturer. A twisted pair format commonly used for these wires ensures the least amount of magnetic interference in an audio signal.
There are two conductors inside the covering of a balanced audio cable. The difference in the positive and negative polarity while the noise is affecting both wires causes the cancellation of noise. Called common mode noise rejection, this is one quality an audio specialist typically looks for in equipment. Coaxial cables are rarely used in systems for audio because they create high levels of noise by concentrating it onto the electrical conductor.
Cables that carry balanced audio feature a specialized "XLR connector," a round connection device using pins to attach to ports in audio mixers and stage lighting equipment. Another type is the tip, ring, and sleeve (TRS) connector that is a cylindrical shaped jack used in stereo and telephone systems. For balanced audio, there is no shield to block inference from the wires; a shield is connected where the cable and the audio equipment connect. The design of the cable is intended for interference-free audio and is found in retail stores that sell audio equipment.
Unbalanced wires and equipment are not usually part of audio systems because the sound is not clear. Sometimes consumer electronics mix balanced audio with unbalanced systems but are not as effective as balanced devices alone. A balun, or a device that can link both systems, can be used to make them compatible with one another.
The benefit of using balanced audio cables is that they can carry signals far without any degradation because of noise. Conductors extending through the center can make the wires not only resistant to noise, but more flexible as well. The shield also does not have to cover the whole wire, which will then be not as bulky and easier to move around. Shields are used mostly for the inside conductors as well as the ends of the wire connectors, but many wires for balanced audio don’t include a shield in their design.
