The quality of audio recording for music or podcasting can suffer considerably due to the presence of background noise. Background noiserefers to any unwanted noise from the surrounding that becomes an unintentional part of the recording. Background noises over which you have some degree of control include noises like someone coughing or slamming the door. But noises that are more difficult to control include inherent ambient noises like hiss, clicks, and static or even mechanical noises that result from system itself. Generally, analogue recordings are more susceptible to noise than digital recordings.
Recording Without Background Noise
Given below are some of the main causes of background noise and how to eliminate them:
1. Room Environment
The room environment can be a major source of background noise, particularly if you are recording at home. Ensure that the recording environment is quiet. Always switch off the TV and other devices like fans and air conditioners that can contribute a low hum to the recording. Close all the doors and windows and draw up the curtains. It can get a little stuffy after a while and its better to do a session of 15-20 minutes at one stretch.
2. The Computer Fan
A sensitive microphone, placed too close to the computer (or laptop) can capture the sound of the computer fan, the Power supply and the hard drives. The solution is to place the mic. no less than 6 ft. away from the computer. Use a directional microphone and point the side that has maximum sensitivity away from the computer. You can also buy quite cpu fans, which will cut down noise in your recording. (you will be surprised how any brands are there for them!)
3. Internal Noise from the Sound Card
The computer’s internal components like the sound card may generate considerable electrical noise that can introduce heavy background noise in your recording. To figure out if your system is producing internal noise, test with “no inputs” and record for a while. If your recording reveals static, it confirms internal noise. Shielding the sound card is an option. But the best solution is to replace the sound card. The better the sound card, the lower the internal noise. There are some great USB soundcards out there for as low as $200, which provide almost zero noise.
Tips to Eliminate Background Noise
Once you have addressed the common causes that lead to background noise, it is essential to follow some tips that can eliminate them effectively
1. Mounting the Microphone on a Stand
Setting up the microphone on a stand helps reduce vibration. If you hold the microphone in your hand, it may pick up the movement of your fingers on it during the recording. A microphone stand enables a hands free recording.
2. Use of Pop Shield For the Microphone
Certain sounds like ‘P’, ‘B’ and ‘S’ tend to release a burst of air while being uttered and these incorporated into the recording are very difficult to remove. They can be eliminated by covering the microphone with a pop shield. The pop shield is essentially a circular frame with fine sheer material stretched across it and eliminates the ‘pop’ of these sounds.
3. Use of Proper Recording Levels
By setting the recording levels high, it is possible to mask the background noise. A high level of input not only masks the noise, it also gives a better signal to noise ratio. However, very high levels can cause the signals to clip resulting in distortion. Set the input level to about -6db, this allows enough headroom and also avoids distortion.
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By Rajiv Agarwal