Cables are essencial for most of the work in sound recording because they are very reliable and durable compared to wireless systems. The most common cable is the XLR cable for connecting microphones to external devices and recorders, however what is the difference between an often more expensive balanced XLR cable compared to an unbalanced one?
The easiest way to understand the difference is the signal separation that takes place inside the cable. Common cables like plugs for a kettle have 3 separate cables inside one for ground, one for positive and one for negative. A balanced cable would use all 3 and since each one is doing equal work is balanced. However unbalanced have or use 2 of these wires which means the negative wire is also doing the work of the ground wire.
Balanced cables mean they are less susceptible to extraneous noise. Their XLR connectors often have a locking mechanism that makes the connections more reliable and more difficult to accidentally unplug. Unbalanced phone, mini and RCA connectors are not hearty and can be easily damaged and dislodged from their inputs. Balanced cables often also include a tight metal mesh wrapper that acts as an electronic shield to protect them from interference. Electricity can generate hum through a broken cable or a damaged connector. It can even arise simply by laying a power cable parallel to an audio cable. The upshot to all this is that hum in a cable can ruin an audio recording
Unbalanced cables and high impedance accessories are fine when work with very short cable runs. Also, an inexpensive microphone and unbalanced cable is almost always better than just using the on-camera microphone. In a professional situation, you want to isolate the sound source, and eliminate any potential for hum. Balanced cables eliminate hum. Using an external microphone of low impedance is best in an interview situation or when it is not possible to get close to your subject.
Feel free to ask any questions and leave comments,
Thanks,
- Matt Price
