Experimenting with a noisy audio

Special Interest Groups Audio Processing
1

Hi everybody!

I have this very noisy audio and I’m trying to reduce the noise a little bit.

Here are the frequency analysis of a small sample of noise (left) and a small sample of noise & voice (right), in logaritmic and linear plots.

http://www.glowfoto.com/static_image/06-081726L/9346/jpg/12/2010/img6/glowfoto

So far I’ve tried the noise removal feature with default settings but I got poor results.
Then I tried to use high pass filter (above 500 Hz) and low pass filter (below 4k Hz) and it looked a little better.
Lastly I played around with the Equalizer cutting a lot below 500 Hz and above 2k Hz and that seemed to be the best solution I was able to find!(but I’m not sure what would be the best equalization curve to get the most noise reduction)

http://www.glowfoto.com/static_image/06-100940L/7880/jpg/12/2010/img4/glowfoto

Being a total noob at audio processing, I wanted to know if I’m doing it right or are there other ways to get better results?

Thanks!

2

Then you may not know that applying noise reduction in Audacity is a two step process:
First you have to select a region of the audio which is only noise to capture a noise profile, then click on “Get noise profile” to capture it … http://manual.audacityteam.org/index.php?title=Noise_Removal
After you have captured the noise profile, select “Noise removal” again from the “Effect” menu, then select the region of audio you want to reduce the noise and click on preview, (typical settings are 10dB for noise reduction, 500Hz for frequency smoothing, and 0 for attack decay time).

If the recording is voice (rather than music) the minimum bandwidth for good quailty speech is around 200Hz - 5000Hz, (will sound like a telephone),
300 - 3000Hz is about the least you can get away with for intelligible speech (will sound like poor telephone connection)

[ BTW your glowfoto.com photos aren’t visible in your posts ]