Tonight's mission is to rid a recent interview recording of an unbelievable amount of noise. I was using the Olympus TP-7 Telephone Pickup Hands-Free Cable, which seemed to work okay for my last phone interview, but maybe I was using the other DECT handset or something, because this particular recording was dreadful. So, enter Audacity. This is a free, open source sound editing package that has capabilities way beyond my needs but providing the functionality I need to clean up the MP3 file.
For the kind of interviews I'm working on, for research rather than broadcast purposes, the most useful tool is the Noise Removal effect.
To use the Noise Removal feature:
1. Find a section of your recording that is just noise.
2. Go to Effects and then Noise Removal.
3. Click the Get Noise Profile button, then select a section of noise from your recording. If you select a really small section (less than a few seconds long) it will look like nothing has happened. That's fine -- Audacity will have grabbed the noise, so you can go onto the next step. If you grabbed a longer section, you may have to wait a second or two while it processes.
4. Click Ctrl+A in your recording to select the entire track.
5. If the Noise Removal window has closed, go to Effects and select Noise Removal to reopen it.
6. Click Preview. Audacity will play a short section at the start of your recording with the noise removed.
7. Make any adjustments to the slider (click Preview to hear the difference) until you are happy with the result, and then click the Remove Noise button to go ahead with the process
8. Noice removal will begin and will take a few minutes, depending on the length of your recording.
9. Save your edited file to MP3 (or other format) to use in your transcription software.
And that's it. Easy peasy -- with the only requirement being some patience! Next load it into your transcription software and away you go. What? You don't have any transcription software? Then my next post is for you!
For more information about Audacity's noise cancellation feature and other ways to clean up an audio recording, visit the Audacity wiki.
