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on 2011-12-09 at 13:55 Michael Mol wrote: |
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>I couldn't tell you if it's necessarily "good", but Audacity has a |
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>noise filter. |
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that's exactly what i was about to reply. |
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and if you want to try a CLI tool, sox provides a similar utility. |
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noiseprof [profile-file] |
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Calculate a profile of the audio for use in noise reduction. |
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See the description of the noisered effect for details. |
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noisered [profile-file [amount]] |
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Reduce noise in the audio signal by profiling and filtering. This |
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effect is moderately effective at removing consistent background |
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noise such as hiss or hum. To use it, first run SoX with the |
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noise‐ prof effect on a section of audio that ideally would contain |
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silence but in fact contains noise - such sections are typically |
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found at the beginning or the end of a recording. noiseprof will |
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write out a noise profile to profile-file, or to stdout if no |
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profile-file or if `-' is given. E.g. sox speech.wav -n trim 0 1.5 |
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noiseprof speech.noise-profile To actually remove the noise, run |
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SoX again, this time with the noisered effect; noisered will |
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reduce noise according to a noise profile (which was generated by |
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noiseprof), from profile-file, or from stdin if no profile-file or |
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if `-' is given. E.g. sox speech.wav cleaned.wav noisered |
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speech.noise-profile 0.3 How much noise should be removed is |
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specified by amount-a number between 0 and 1 with a default of |
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0.5. Higher numbers will remove more noise but present a greater |
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likelihood of removing wanted components of the audio signal. |
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Before replacing an original recording with a noise-reduced |
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version, experiment with different amount values to find the |
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optimal one for your audio; use headphones to check that you are |
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happy with the results, paying particular attention to quieter |
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sections of the audio. |
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On most systems, the two stages - profiling and reduction |
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- can be combined using a pipe, e.g. sox noisy.wav -n |
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trim 0 1 noiseprof | play noisy.wav noisered |
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never compared the results, if you do, i for one would be very interested |
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in your experience. |
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IMO, it's much better to remove noise by small amounts in successive |
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passes (taking a new profile each time, of course), than trying to remove |
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too much noise in one pass. |
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let us know how it went! |
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lj |