Removing Hiss with Audacity

Discussion in 'Guitar Gear Talk Forum' started by rickkkyrich, Sep 3, 2010.

  1. rickkkyrich

    rickkkyrich Guest

    Well i came across this article and found it helpful so sharing with you all. I rip it off from some other site.

    Removing Hiss with Audacity
    I've tried various tools to remove hiss (or noise) from home recordings and I think Audacity has the best noise removal tool of all. While most other software packages use a noise gate to remove unwanted noise, Audacity goes about it differently.

    I won't launch into how the techniques differ but I shall say this, Audacity's tool is far superior to any other I've tried. The end result is noise removal not only from "gaps" (the parts where the recording is supposed to be silent, like spaces between sentences and paragraphs) but also from spoken parts.

    Let's say there's a constant hiss in a recording. That hiss will be audible even "below" the spoken parts of the recording (you'll hear the hiss when you're saying something too). Noise gates remove the hiss from the gaps but the hiss will still be audible in the spoken parts. Not so with Audacity's Noise Removal tool. If you use Audacity to remove noise you'll have no hiss throughout the recording.

    Here's how to remove hiss (noise) from a recording:

    Open a pre-recorded file or record your piece.

    Click-drag a "gap" (part where there was nothing being said - the beginning of a recording usually has a gap) to select it:

    This is a sample of the noise or hiss that you want Audacity to remove.

    Next, go to Effect--> Noise Removal

    Select that and you'll get the following dialog box:

    Click the "Get Noise Profile" button. This tells Audacity that what was selected is noise that you want removed from the recording.

    You'll be taken back to the wave form of your recording. Hit Ctrl+A (keeping the Ctrl key pressed, hit A) to select the entire recording. Your recording should look a bit like this:

    Go to Effect--> Noise Removal again

    Move the slider to the left so it's positioned about halfway between the start and its current position:

    Next, hit the "Preview" button in the dialog box:

    Listen to the preview. If there's still noise (99.99% of the time there won't be) move the slider to the right. If there's distortion of the voice move the slider to the left. (If there's noise AND distortion have your sound card and microphone checked by your hardware guy).

    When you're satisfied that the noise has been removed without distorting the voice hit the "Remove Noise" button. You'll get the following message:

    You'll then be taken back to the wave form view (you'll notice that the recording looks much cleaner, in the sense the jagged waveforms in the gaps have given way to flat lines). Listen to the ENTIRE recording and check for distortion in the voice. If there is any distortion hit CTRL+Z (holding down the Ctrl key, hit Z) to undo the noise removal, go back to Effect-->Noise Removal, move the slider further left, hit the Remove Noise button again and listen to the entire recording again. Keep doing this until you're satisfied with the recording.

    As I said earlier in this post, if you are unable to remove the noise completely without distorting the voice, you have a problem with your hardware and need to have it checked by a competent hardware guy. Yes, Audacity is indeed that good. I've delivered studio-quality sound to clients using nothing more than my home computer, a $2 microphone and Audacity.
  2. thehundredthone

    thehundredthone New Member

    1. Is this an original post by you?

    2. The noise removal isn't studio quality. The more noise you try and remove the more it will eat into the sound. No algorithm can successfully remove only the noise because even noise has some frequencies in common with the recording.
  3. rickkkyrich

    rickkkyrich Guest

    No its not an original post. I said it in the very first line.
    and yes noise can not be completely removed. If you have some other ideas bout how to remove the hiss(noise) please do share. It'll be helpful for many people. Most importantly for myself. :)

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