If it's a high pitch and confined to a relatively small bandwidth like I think you're describing, you could probably remove it with a notch filter pretty easily. You may want to start by looking at Freaqtweak. -Reuben -----Original Message----- From: Tim Beauregard [mailto:helycos@lycos.co.uk] Sent: Monday, August 25, 2003 4:18 PM To: linux-audio-user(a)music.columbia.edu Subject: [linux-audio-user] Noise removal, what filter is best? -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, I'm looking for a filter/software to remove noise from a sound file. I'm not an audio expert so will try to describe the noise in a way that you out there might be able to put a name to it and recommend a suitable filter/software to remove it. It is a short sharp blip, fairly high frequency, sounds like a compass point stabbing glass. It occurs as often as every minute or so in the two hour sound file. I obtained this file by recording DAB radio here in the UK. I'm presuming the noise is derived from errors in the transmission or analogue to digital conversion phase of the broadcast. I think it is due to a signal exceeding line volume. I've tried the gramofile filter 'Conditional Median Filter II', which failed to remove the noise. If necessary I could email a sample of the noise. I'm using Debian 3.0r0, 2.4.18 kernel. Thank you in advance :-) Tim Beauregard