background noise

I have made some recordings in MP3 but they have some clicks and bumps and junk on them that I’d like to be rid of. Is there a way of using Audacity to clean these up, or will I need to rerecord them?

It’s always best to prevent or avoid noise, so re-recording is probably the best option. Pros still record in soundproof studios with good low-noise equipment, and on-location movie dialog is re-recorded in the studio, because even pro noise removal software isn’t perfect.

And, sometimes you can get artifacts (side effects) and “The cure is worse than the disease”

You can try The Click Removal or Repair effects, or you can sometimes use the Draw Tool to re-draw the waveform. You’ll need to zoom-in and visually find the defect in order to use the Repair effect or to re-draw the waveform.

For transient noises like this, the regular Noise Removal effect won’t work… It works best with constant low-level background noise, such as a tiny bit of analog tape hiss… It best when you don’t really need it.

Sometimes it’s easier to find a defect by viewing the Spectrogram. The Spectrogram view is selected from the drop-down track menu to the left of the waveform display. After you find and zoom-in on the defect, you can switch back to the regular waveform display.

There are also [u]special purpose applications[/u] for removing “snap”, “crackle”, and “pop” from digitized vinyl records. Sometimes those are good for repairing other short-duration defects that are not actually from vinyl.

Audacity does not record “in MP3”. Did you record them on some kind of MP3 recorder?

If you recorded in Audacity, then Audacity records in a very high quality “uncompressed” format that is ideal for subsequent editing and processing. If you exported from Audacity as an MP3 and you also saved the Audacity project, then it would be best to do your editing / processing in the original Audacity project rather than the MP3. MP3 encoding is “lossy”, which means that it discards some of the audio data in order to reduce the file size. The effect of this is to cause a certain amount of “blurring” to the audio which can make subsequent processing less effective.

Also, the quality loss occurs during encoding, and Audacity needs to decode the MP3 in order to work with it, which means that if you want the final product to be MP3, then the audio will need to be re-encoded, which causes further loss of sound quality. The general rule is: convert to MP3 only as the final step of the production process, and only then if you really need it to be in MP3 format, otherwise use a high quality format such as WAV.

If MP3 is all that you have, then yes you may still be able to make some improvement, though the quality will not be as good as if you had worked with the original project or a high quality WAV file. How bad are these “clicks, bumps and junk”? Perhaps you could post a short sample (see here for how to post an audio sample:

As DVDdoug wrote, “prevention is better than cure”, so if you are able to make a new recording without those problems, then that would be the best option. However, if the problems are not too bad, then it may be possible to do an adequate fix, so feel free to post a sample and we’ll be happy to take a look.

Thanks so much, fellas. Appreciate it. I’ll re-record them. I have a walk-in closet that I use. I use an H4N recorder, which records in WAV and then I convert it to MP3 for the audio book guys. I’m an author with 16 books, so this is going to take a while!
Thanks again,
Slim Randles