Undoing Noise Removal


I recorded a phone interview a few days ago. Afterwards I noticed a lot of fuzzy static on the recording. I’m new to Audacity so I tried using the noise removal effect. I must have used it too strongly, because I just reopened the file, and it’s impossible to hear my interviewee’s voice! I can’t figure out how to undo the noise removal at this point.

Is there a way to change the recording back to its original state? Thanks for the help!

Probably not. Audacity Projects do not save UNDO and if you stepped on the original sound file with your correction, that’s the end of the show.

Audacity does not do forensics. We can’t take trash and make it into a clear conversation like in the CSI TV show.

If you did a Time Machine backup between your phone call and the corrections, then your original slightly noisy sound file will be in there. Time Machine is highly recommended and I understand you can do it on-line now. You don’t need the second hard drive.

Never, ever, ever, ever, destroy or damage an original sound file. It’s very common to assume that you have to save corrections or edits over the original capture work. Nobody professional would dream of doing that. It causes problems like you have and also causes you not to get paid.

I recorded a phone interview a few days ago.

How? How did you make the recording? Phone interviews are extremely difficult to do and we’re always alert to ways of making better and clearer recordings.


Well, thanks for the answer, Koz. I can pick out enough of what the interviewee said to have her read it back to me. Not ideal but it’ll have to do.

The other, earlier interviews I recorded, using Audacity, have responded very well to Noise Removal. I just goofed with this one in particular. If you know of better methods for recording sound without the background scratchy noise, then loading it into Audacity, I would love to hear them. I’m not used to conducting interviews at a distance, without my trusty digital recorder, so I’m teaching myself on the fly.

I’m also used to working in ProTools, which I can’t afford to install on my laptop, so I figured with Audacity that I could restore the original file even after saving. I’m not some tech wizard but I don’t think it was such a crazy assumption, requiring CSI-style forensics! Now I’m a little smarter about how to use it properly, and my other interviews have turned out okay.


without the background scratchy noise

Post some scratchy noise here.


Or post longer clips on a public posting service so we can listen. It’s remotely possible for us to take one listen and tell you what button to press to get rid of it.

my other interviews have turned out okay.

How. Did. You. Do. Them?

Here’s a proper land-line telephone sitting on a Louis IV knockoff table in the middle of the room.

Your guest is going to call in fifteen minutes. Your move.


with Audacity that I could restore the original file even after saving.

If you saved or exported the work as the original file name, I don’t think even Pro Tools will be able to help you once closed.

Audacity erases all the buffers and caches when you close. You can back up to earlier versions of any current work as long as you don’t close Audacity. Audacity Projects save your look and feel, your graphics positions, clips, locations, etc, etc, but not UNDO.

No Apple “Time Machine” backup? Highly recommended. Sooner or later you’re going to trash something that ought not be trashed.

“Oh man, I would kill to have that software installer I used six months ago.”
“Hold on. let me flip through the backups. Ummmmm. Here it is.”