Eliminating A/C Noise from Your Recordings

On those sweltering summer days when it’s best to move that special family gathering indoors, you’ll undoubtedly be grateful that you made the choice to install a reliable air conditioning system.

Family gatherings often include family pictures and videos. In the case of the latter, the last thing you’d want on your home movies is the continual sound of an A/C unit or system running in the background.

Here are some tips to prevent A/C background noise from showing up on your recording, courtesy of a sound expert:

Avoid noise reduction plugins for your computerized programs. According to the expert, these add-on programs might work well for some people part of the time. However, in a majority of cases, “you can’t remove much noise without seriously degrading the rest of the recording.” Instead, focus your efforts on reducing or removing noise before you begin recording.

One way to do that is to work toward establishing maximum acoustic separation. The best ways to accomplish this are to use cardioid mics that are angled away from the origin of the noise; to increase the distance between the noise source and the microphone; to use acoustic treatments behind microphones in order to absorb ambient room noise; and, to use dynamic mics to cut down on room sound.

You can also take steps to optimize your air conditioning system. For window units, this means sealing up all cracks in the window opening. Much of the noise that shows up on recordings comes from the outside world, not the unit itself. For central A/C systems, check to make sure that the vent covers aren’t rattling, as that can be a major source of unwanted noise.

You can also try to construct a DIY sound dampener out of plywood and acoustic foam. However, even that solution doesn’t always guarantee noise-free results.

If all else fails, consider the oldest trick in the book: Turn the A/C off when recording and switch it back on when your recording devices are idle. This might take some coordination, and you will lose some element of spontaneity with your recordings. However, years from now, you may find that resorting to this common-sense approach was worth it for posterity’s sake!