The ability to record audio is becoming commonplace in today's society. More and more personal devices, such as PDAs, cell phones and laptop computers, are coming equipped with some sort of recording device. One of the major problems with recording with these devices is background noise that can ruin the quality of the audio. Fortunately, there are many software options to help you remove this noise.
Find a few seconds of audio that only contains the background noise you want to remove, and nothing else. You can usually find this sound at the beginning or end of the audio file.
Find the selection tool in the Audacity tools tool bar (it looks like a letter I) and click on it. Using your mouse, click and drag over the selection of audio on the waveform audio file (WAV) that has only the background noise. Make use you only select the noise, and not any sounds you want to remain in the file when you are finished.
Select "Effect" from the top menu, and then scroll down to "Noise Removal."
Click on the "Get Noise Profile" button on the "Noise Removal" tool screen. It will use the selected piece of the file, and attempt to remove as much of this noise as possible.
Select the entire file. You can do this by clicking "Ctrl-A," or by clicking with your mouse on the left-hand side of the WAV, beneath the name of the file. Select the entire WAV form.
Go back and select "Effect/Noise Removal" again. You can change the settings, such as "Noise Reduction" and "Frequency Smoothing" using the sliders. You can click the "Preview" button to hear the differences. When you are satisfied, click the "OK" button.
Select a section of noise that is at least half a second long.
Select "Effects" from the top menu, and then scroll to "Restoration" and click on "Capture Noise Reduction Profile."
Highlight the entire WAV from in the main screen to remove noise from the whole file.
Select "Effects/Restoration/Noise Reduction." You can experiment with the settings until you are satisfied.
Save your file.
Import your file.
Open the "Track Info Pane." Select the "Edit" tab and click the "Click here to add an effect" button.
Select "Speech Enhancer" from the GarageBand effects menu.
Select your microphone type and voice type (male, female) and the level of noise reduction you desire.
Save and export your file.