Re: [linux-audio-user] Noise removal, what filter is best?

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Anahata wrote: | Noise removal tools like that in audacity are for removng a constant | background hiss or hum and would not be suitable for an occasional loud | sqeak. I'm surprised that gramofile does not do anything for it, but I I could wade through all the filters and tweak them til I get a (near) satisfactory result. | think your best bet in this case may be to use a sound editing tool like | audacity and manually cut the noise blips. If they are much highe | amplitude than the normal sound they should show up on the display; | otherwise you'll just have to locate them by ear. When you find one you | can either cut the noise out (shortening the recording by the length of | the section you've cut out) or use the amplitude envelope tool to make a | rapid fade out/fade in over the noise. The first method will cause a | time discontinuity: the second may cause an audible droput in the sound. | It depends on the nature of the recorded material and the length of the | noise burst and you'll have to experiment to see which is the least | objectionable. Good advice, sometimes I can see the sound, sometimes not. Will try the fading technique. | If the noise is at exactly one frequency, it may be possible to select | a short section containing the noise and apply a filter with audacity, | with a deep notch at the frequency of the noise. I wouldn't advise | applying such a filter all through the recording because it would | probably not sound very nice, and it's a pity to spoil a minute or good | sound just to reduce the effect of a fraction of a second of noise. | Again you'd have to do this for each noise burst, but with a bit of luck | (i.e. if the frequency is the same each time) the same filter setting will | work on each one. And this is worth a try too. Lots to get my teeth into. Thanks aplenty. Tim |