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