notch filter good for cleaning out static noise?


in about 1.5seconds of audio, i noted 2 instances of what sounded like static noise.

trying to remove them, i used frequency analysis to identify the values of the various peaks before applying the values in notch filter in an attempt to remove them.

may i ask what is the probable frequency range of static noise because after applying values from 60hz to 1200hz the noise remains

attached is the screen capture of the frequency analysis


Notch filters can only remove a tone of constant frequency. Whereas “static” [hiss type] noise occurs across a wide-band of frequencies : a notch filter won’t remove “static” hiss.

If it’s only a few “instances” of an unwanted sound, you could try Audacity’s spectral selection tool if you can identify them on the spectrogram view.


the static noise are well defined as vertical columns and appear on the left channel slightly before 1.5s and on the right channel at approximately 0.27s and 1.4s.

kindly advise as the spectogram example shown involved removing horizontal column centred around a particular frequency

I’d use Audacity’s spectral edit tool [shelves] to nibble-away at the bursts of noise …
Demo of Audcaity's spectral edit tool (shelves)_ .gif
spectral Edit on sleves, -10dB setting.png
Once you’ve selected “spectral edit shelves” from the effect menu, you can apply that effect repeatedly by pressing “Ctrl”+“R”.

You can also try the [u]Click Removal[/u] or the [u]Repair[/u] effect.

If you’re not getting good results, there are also [u]special purpose applications[/u] designed for removing clicks & pops from digitized vinyl. These can work well on short-duration defects even if they are not from vinyl records.

Click Repair and Wave Corrector are popular and affordable (after the free trial), and they work automatically which is good if you have a large number of clicks & pops. I have Wave Corrector, and I have Wave Repair which works well if you want to manually identify & repair the defects without “touching” any of the other audio.

Of course, it’s best to prevent defects whenever possible.

thanks for the advice

the spectral edit tool proved more than sufficient to remove the static noise so i did not have to move on to other options.

but there is 1 thing about it which maybe worth highlighting and incorporating into future tutorials: the default frequency range of 0-8khz is shown but when the full visible spectrum is highlighted(as in my case where the static noise forms a straight vertical column) the chosen area actually extends beyond what is visible, ie beyond 8khz. this point is not immediately apparent to the user, at least not to the novice, for whom the tutorial is primarily targeted at. i was getting constant errors about frequency selection, rechecking and reapplying the spectral selection settings both in the preferences menu and track control panel. hence, besides a pounding headache, i did not get anything done yesterday, .

until today i figured out that there must at least be a small gap in the highlighted area at the top so that the chosen area does not extend beyond the default 8khz range. and this is also the reason for the late reply

if the tutorial can be updated, might be able to save the next person who reads it a few hours

Please advise what tutorial you are referring to. This ?

It might help to enable View > Toolbars > Spectral Selection Toolbar which shows you the selected frequencies. Yes you are correct if you extend either edge of a frequency selection outside the frequency range you can see, then that frequency becomes undefined. I agree that is not completely obvious without Spectral Selection Toolbar on.