A Reader Asks:
I notice a distinct chirping or buzzing in a defined, rhythmic pattern in the audio portion of my production. What causes this and is there anything that I can do to prevent it?
Many issues can cause chatter or noise in audio systems. Some of the most frustrating to deal with lately seem to be coming from portable wireless devices.
Cellular communication can be the source of this interference when a subscriber is using their wireless device near some speakers or poorly shielded audio cables, controls and other equipment that can resonate radio frequencies (RF). One of the biggest causes is shielding, or lack thereof. What is happening is poorly shielded gizmos can act like an antenna picking up the cell phone’s generated frequencies. At a very basic level, you are hearing someone’s telephone communication.
Some telephone networks cause more electronic noise than others because of things like, how often they communicate with devices, the frequency bands they use and how much power the device emits.
The amount of noise caused by cell phones and networks when near sensitive audio devices is related to how efficiency the telephone communicates with the network and stays connected. Some telephones need to talk with the tower more often than others.
Experts say that the interference is an intrinsic part of cellular technology and not much can be done to prevent it. We live in a very noisy world from a radio frequency standpoint.
Solving the issue is not easy. One thing that will help is to do away with copper cabling all together and install fiber optic cable but other hardware is still open to the problem. The best way is to insist that everyone within the production’s proximity turn-off his or her cellular devices. Not set to vibrate-Power-off completely! All well and good unless you pull up your mobile production unit near an offending system’s cell site.
Part of the responsibility lies with the manufacturers to provide better shielding and systems in their own devices. Part of the responsibility lies with audio and video system installers and designers to address this problem and design-in better RF shielding to prevent or at least minimize impact.
- Experiment with wire dress
- Be sure all shields are soldered
- Use quality cable.
- Use quality connectors
- Maintain a totally balanced audio system
- Have a good maintenance program -33-