Mic noise appears when sound is transferred from one device to another. Here's how to reduce it:
On laptop recordings:
Windows Vista, XP, and Windows 7:
- Go to Start
- Select Control Panel
- Open Hardware and Sound
- Choose Sound
- Choose Recording
- Find the Microphone bar
- Right-click on the Microphone bar, and then select Properties
- Find the Levels tab, and look for the Microphone Boost tool
- Move the dial all the way down on the Microphone boost
- Move the dial all the way up on the Microphone
- Next, go to the tab marked Enhancements
- If they aren't already ticked, tick the following boxes: Noise suppression and Acoustic echo cancellation
- Press OK
- To test the noise, go back to the Recording menu
- Go to Listen to this device
- Click OK
OS X (MacBook and MacBook Pro's using OS X versions 10.4.6 and later):
- Go to System Preferences
- Find Sound preferences
- Look for the Ambient Noise Reduction tool
- Check the box marked Use ambient noise reduction
- Move the dial up and down (until you find the right balance of audio output v. background noise)
- Check for nearby devices which might cause interference
- Switch off anything noisy (i.e. ceiling fans, televisions, laptop fans, or traffic noise)
- Speak directly into the microphone
- Close doors and windows
- Make sure that the mains electrical cables are not running across signal cables (i.e. if you're using a wireless mic). The same goes for mains cables and audio cables (i.e. headphone leads), because the electromagnetic force which surrounds mains cabling can cause interference.
- Use the right sort of mic. A general-purpose mic won't pick up quiet acoustic instruments or subtle sounds. You need a microphone designed to pick up difficult-to-record sounds (ask for a back-electret mic)
- Use a separate microphone - not just the one in your computer
- Use a digital recording device separate from your PC
On headsets and headphones
- Check the headphone jack - make sure it is securely plugged into the device, and that it has been plugged into the mic jack (and not the audio input jack)
- Try a different power socket - all electrical circuits produce noise
- Listening through a laptop computer? Unplug the power cable and use the computer's battery power.
- Make sure the ear buds are properly inserted into your ears - windy conditions can affect the audio output
Noise reduction accessories
- There are several good free online software downloads for editing video and audio recordings.
- Audacity is a free online tool which is designed to isolate and remove unwanted background noise. Other good alternatives include WavePad, and Wavosaur, but you can search for 'free noise reduction software' on Google and experiment with different software downloads.
- When you start searching, make sure that you choose a download for sound editing software and not a noise reduction tool for photography .
- Mac has a feature called GarageBand which is an sound editing package designed for musicians - it comes with most OS X packages but is also available as an App on iTunes.
Use a Mic Preamplifier. This eases the transition between your Mic and other equipment (prepares it for transfer).
Invest in a ground lift adaptor for your laptop power supply - these do an excellent job of reducing static noise, particularly if you use multiple sections of recording equipment.
Fit a shock mount to the mic stand to reduce background noise cause by tremors and vibrations.
Use a wind sock - this fits over the mic's head and cuts out unwanted wind interference.