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How do I Reduce Microphone Noise?

Computer users should consider using a standalone mic instead of native mics from webcams, monitors or laptops.
A preamplifier can be used to reduce microphone noise.
A microphone is crucial for producing professional quality audio.
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  • Written By: S. Gonzales
  • Edited By: Bronwyn Harris
  • Last Modified Date: 10 September 2014
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Microphone noise can be an unwelcome nuisance to anyone attempting to record audio. Thankfully, there are simple actions that can be taken to reduce or eliminate it completely. Start by checking where you have connected the microphone. Noise can be caused when you plug the microphone into a line input jack instead of the microphone jack, for example, and a simple switch may eliminate unwanted sounds.

Check the microphone type next. Microphones that are less likely to produce noise are of the electret condenser variety. To determine whether a microphone is a electret condenser, look at the plug and find the tip. If it's silver and has grooves dividing the plug into three, then the microphone is an electret condenser that can easily connect to a computer's sound card. Dynamic microphones, on the other hand, may present problems with noise due to their increased sensitivity and issues with connecting to sound cards.

An auto-tuning wizard available on some computers may be able to stop unwanted noise. You should be able to test the hardware for any malfunctions, and some tools will even let the user participate in a live test of the microphone to help calibrate a microphone's recording volume. Users who choose to do this must speak with the microphone at an average distance so as not to compromise the results.

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In addition, you may be able to reduce microphone noise by downloading programs equipped to handle the noise via software. Software designed to use external microphones for recording may have options to reduce hissing sounds, for example. Other software may clean up unwanted sounds automatically. If unwanted noise persists, try using a preamplifier or a different microphone that has been researched and chosen based on its compatibility with the recording device.

Computer users should also consider using a separate microphone specifically for recording audio. Devices that include integrated microphones, such as webcams, do not always provide satisfactory recording results. This is especially true when the microphone is intended to be used in peer-to-peer audio communication, like Voice over Internet Protocol (VoIP) applications. If the intention is to capture precise audio, like in music recordings, you may have better luck recording with a digital recording device that is separate from a computer. After the recording is finished, a computer can be used for editing purposes.

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anon235493
Post 5

What people call microphone noise may not be the fault of the microphone. There are three main sources of noise when using a microphone:

1.) Background noise in the environment, such as sounds made by air conditioners, road noise, or the coughing of an audience.

2.) Noise inherent in the preamp that the microphone connects to. All electronics add noise; cheap microphone preamps noticeably so.

3.) The self noise of the microphone.

Sound levels, including noise, are measured in decibels of sound pressure level (dB SPL), such that 1 Pascal of sound pressure is about 94 dB SPL. The quietest sound that can be heard is about 0 db SPL, a quiet room you record in might be about 35 dB SPL, a TV at normal volume might be about 70 dB SPL, and so on.

A condenser microphone specification typically lists how noisy the microphone is an equivalent db SPL level. So, for instance, a microphone with a noise rating of 16 db SPL is quieter than one with a noise rating of 25 dB SPL, but even 25 dB SPL is quiet enough so that its noise would hardly be noticeable when recording in a room with an ambient noise level of 35 dB SPL.

Sometimes a condenser mike will list the signal-to-noise ratio in dB instead of the noise level in dB SPL. But, you can then calculate the microphone's noise level in dB SPL as (94 -- the signal-to-noise ratio in dB).

Dynamic microphones generally don't include a noise spec because their self noise only depends on their impedance and their temperature. It will be lower than the noise produced by the microphone's preamp. For what it's worth, lower impedences (and lower temperatures) produce less noise, and the noise contribution of a dynamic microphone's preamp will be greater than the self noise of the mic.

The noise contributed by the microphone's preamp is specified in a different way than microphones, in units that equate to voltages instead of sound pressures. It takes some calculations to do the conversion to dB SPL based on a particular microphone's sensitivity. (For more details, research selecting microphone preamps range.)

In general, solid-state microphone preamps can be less noisy than tube-based designs, but in any event cheap consumer electronics have poor microphone preamps. So, a noisy microphone preamp may be the source of the "microphone noise" you've been hearing.

nony
Post 4

@miriam98 - If we're not limited in this discussion to just talking about computer microphones, I'd like to suggest the difference between a cardioid microphone and a boom microphone.

A cardioid microphone gathers all surrounding sound, background or otherwise. A boom microphone by contrast filters out surrounding sound and focuses in only one direction--straight ahead. That's why they're often used in camcorders. They magnify the sound that is in front of the camcorder, and soften the sounds that are around it.

You see them a lot in interviews and in documentary films for this very reason. Again, if we're not limited to computers and you're looking to minimize microphone noise, I'd go with a boom microphone as your best bet.

miriam98
Post 3

@everetra - A noise canceling microphone is a good idea, but even with those kinds of microphones you'll have to position them close to your mouth if you want the best results. This is because of how they work.

They try to determine the difference between the ambient noise and noise that is very close. They cancel out the ambient noise and let the nearby sounds go through.

So the point is that whatever microphone you buy, the basic principles for good sound quality are the same. To get the best sound quality, the microphone must be placed closest to your mouth.

everetra
Post 2

I think one of the best ways to reduce noise for computer users is to buy a noise cancelling microphone. These microphones work by cancelling out unwanted background noise.

You’ll usually find them when you buy computer microphones that come with headsets. They tend to cost a little more than regular computer microphones but they’re definitely worth it.

Trevor27
Post 1

Do not underestimate the power of condenser microphones to reduce external noise when recording! In my experience, these are the absolute best for stereo-type recordings (I've recorded as a musician).

You also want to look into the variety of directional microphones to help compliment the acoustics of your recording room. Your PC microphone probably give you opposite results, by the way.

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