Monthly Archives: August 2013

Reducing Unwanted Noise When Recording

What Is Noise?

In recording terms, noise is an unwanted sound that is captured by our recording equipment. The two main sources of noise in the recording studio are acoustic noise and electrical noise.

The acoustic noise is the noise in the room that isn’t being deliberately produced by the musicians. If you stand silently in a room you will start to notice it. Right now I can hear a humming from my laptop and the TV on standby. I can hear the washing machine from the kitchen and cars on the road outside. These noises are all acoustic noises. They are part of the room I am recording in.

The electrical noise is the noise generated by the recording equipment I am using. Each piece of gear has self noise which is the noise produced just by the gear being switched on. Microphone tech specs often quote the self noise of the microphone. However all the elements of your system will be generating some noise, even the cables.

How to reduce the acoustic noise
Firstly you need to stay very quiet and listen carefully. You will notice all the sources of acoustic noise in your room, as I demonstrated above. For each one you should consider how it can be reduced. Here are some ideas.

  • Move PCs as far away from the microphone as possible
  • Switch off TVs and other electrical equipment at the wall
  • Switch off washing machines or wait until they’ve finished
  • Close the door in the room you are recording in and also the doors to rooms creating noise
  • Place blankets and pillows over the windows to reduce outside noise
  • Use a directional microphone with a cardioid polar pattern. These are most sensitive in one direction so you point them at the source and they will pick up less of the acoustic noise in the room

How to reduce the electrical noise

  • Buy high quality gear that has a lower self noise. Metal is better than plastic
  • Reduce the number of items to the minimum level. Each item adds to the total noise
  • Use short cables as longer cables create more noise
  • Use balanced cables like XLR or TRS which contain an additional wire to cancel noise
  • Place the microphone closer to the sound source to get a louder signal. Each time you increase the gain you introduce more noise so this will reduce the required gain increases

You can reduce noise post production in your DAW but it’s better to get a cleaner signal in the first place by reducing the noise up front.

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