Removing background noise is very difficult. If it is uniform noise, such as white noise on an airplane, algorithms exist for removing these frequency components. But if the noise is uneven and similar in nature, how is your good recording, for example, people speak in the background, street noise, etc. it will be very difficult to separate them. A lot of research has been done on this issue.
At the very least, you need to know exactly what a good sound is and what a bad sound is. For example. if you capture a voice, there may be special audio recovery software available to separate voice from other sounds, for example. http://www.izotope.com/products/audio/rx/ . If you record a voice in stereo, it may be useful for you to analyze the left / right position of the voice, and then remove the components without a voice, matching them left and right.
Re: mkb comments:
- the squelch will mute when the level (of some or all of the frequency components) is below the threshold. Depending on the background noise level, this may help, but often noisy gates are annoying because you will hear the background while your “good” sound is there and there will be silence between them.
- a low-pass filter removes high-frequency components (it passes low frequencies)! Therefore, if your background noise has a high frequency, this can help. A simple FIR or IIR low pass filter is easy to use. But it will also affect your “good” sound if it has high-frequency components.
Florian
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