cooledit2000,noise removal

[Pulock2009]

hiii!!! i use cooledit2000 to edit and give effects to songs. i record these songs from FM radio stations through my mobile. sometimes some 'hiss-like' sounds appear. how do i remove them????thx in advance!!!

[AndyH]

Noise reduction only works well if used properly. It is very easy to screw up the recording with poor settings, but it isn’t that hard to get good results. It is very important to make a good noise profile, which starts with a good noise selection. By making a high resolution noise profile you can more effectively get at the noise without effecting the music or speech.

You will need about 2.5 to 3 seconds of noise (or tape hiss) without any audio. If only shorter intervals exist in your recording, copy and/or duplicate multiple short sections into a new file from which to make your noise profile. It can be best to adjust the boundaries of your selections to zero crossings before doing the copy step so there are no clicks between the multiple pastes in the new noise-only file.

You should listen to your selection of noise-only at high volume to be sure it is indeed only noise.

to make the profile use
Snapshots in profile: 12,000 to 24,000; more is better
FFT: 24000

When you apply the noise profile to the audio, use these values
Precision Factor: 9
Smoothing Amount: 1 (to 2)
Transition Width: -10 dB
NR Level: 100.
Reduce by: Vary to get the amount of reduction you want (e.g. 6dB, 10dB, etc.)

Select a music section where the noise is audible, say 10 seconds or so. Low level music is generally best. Copy this to a new file for testing. Select a portion of it and apply NR. Listen through to find out what the difference from no treatment to treatment will be. When You have the amount of NR you want, go back and apply it to the real file.

You can use preview to test, but you may be disappointed when the real results don’t match the preview very well. This has been my experience.

NR will do three things. Remove unwanted noise of course, but also, with enough NR, low level detail, especially ambience, will start to go too. With too much NR, strange sounding artifacts will be created. However, with the settings I have given, you may be able to do 40dB of Reduce by with no audible artifacts. Long before that point, the hiss is likely to be totally inaudible.