Removing background noise

How do I remove background noise? I have a recording where music is playing in the background. I want to isolate the people speaking in the recording.

You don’t. That is not noise, like steady hum or hiss which can usually be reduced.

It is part of what you recorded.


I cannot provide a concrete solution. But I know that great progress has been made in the area of speech recognition. This works even with a good portion of background noise, as can be verified with an off-the-shelf Smart-phone. I’m not that much an expert on speech recognition, but AFAIK it is based on detecting formants to a large extend. So, if speech can be extracted successfully from a “noisy” signal, it should also be possible to do it the other way around, i.e. filter out all the rest. You would pretty much zero out those frequencies where you have not detected speech (formants) in the current frame. However I don’t know if anybody has actually tried that before…

We have a proposal for source separation ( ) that would work on sources identified by audio diff ( ).

It’s some way in the future.


Number four.

The Four Horsemen of Audio Recording (reliable, time-tested ways to kill your show)
– 1. Echoes and room reverberation (Don’t record the show in your mum’s kitchen.)
– 2. Overload and Clipping (Sound that’s recorded too loud is permanently trashed.)
– 3. Compression Damage (Never do production in MP3.)
– 4. Background Sound (Don’t leave the TV on in the next room.)