Cool Tools
Audacity
This is an instruction for using the Noise Removal filter in the audio editor Audacity.
I was able to use the freebie audio editor Audacity to remove the sound of a two-tone intrusion alarm from the audio of a cable talk show that I edit. It's an advanced technique where you export your audio track out of Premiere Elements and doctor it in another application. You "sample" the unwanted sound (noise) and apply it back into the soundtrack with a special function provided. Seems almost miraculous in how well it works.
Create a work folder in My Documents. Name it something like AudioWork. Decide on a name for your audio file, such as AudioBad.wav (it will be exported as a .WAV audio file). In Premiere Elements, select the clip with the audio problem. Include only the portion with bad audio -- razor the clip if necessary. Then set the Work Area Bar so it covers just that clip, only. You can do that by using the Page-Up and Page-Down keys to place the CTI at the beginning and the end of your clip. Then use Alt-[ and Alt-] to set the WAB.
From the File menu select Export/Audio. The Export Audio dialog box will appear. Type in the selected name for your file but, before you save, click on the Settings button. In General, the settings should be Windows Waveform and Work Area Bar. All the other settings should be OK as is. Click OK to save, and click Save to save your audio file to your selected folder.
The first thing you need to find is a 'gap' in the dialog containing just the noise you want to eliminate, so that Audacity can use it as a 'noise sample'. You need 1 second, perhaps 2 seconds, or even more would be better. Audacity has a 'Noise Removal' effect that will mathematically subtract the noise sample from your entire WAV file. I find it easier to find a 'gap' in the audio by zooming in on PrEl's Timeline window. Make sure you see the audio waveform on the audio track. Record the minutes and seconds on the timeline for the start of your clip (ignore frames). After you have found an acceptable gap, record again the minutes and seconds, then subtract to find the corresponding time from the start of your WAV file in Audacity.
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Open your exported WAV file in Audacity. On the timeline find your approximate time from the start and click inside either (stereo) track. Use Ctrl-1 to zoom in to a magnified timeline. You should now see your previously identified audio gap nearby. Re-set your time indicator (the verticle line you just created) to the left-most portion of the gap. Move your mouse pointer near to the time indicator and it will become a hand with a finger extended. Left click and drag to the right-most portion of the gap. Now you can click the green play > arrow above and hear your noise sample. You can re-adjust the start and end of the selected sample area with the hand-finger pointer by dragging again.
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Here comes the cool part. Now that you have your noise sample selected, you go to the Effect menu and select Noise Removal. In the Noise Removal dialog box click the 'Get Noise Profile' button. The Noise Removal dialog box disappears! Now, use Ctrl-A to select your entire WAV file. Again select the Noise Removal dialog box and click the 'Remove Noise' button. (Do NOT adjust the Less/More slider!) You now a have a noise-free WAV file! Save it as another name such as AudioGood.wav
Note on the Less/More slider: the slider is best left in the default position in the center. The noise reduction can be so effective, however, that the background of the sound track may end up being too quiet! In that case use slightly Less reduction. Using More reduction always results in audio artefacts and is not recomended.
Use Add Media in PrEl to import your restored audio file. Now you need to replace the existing audio. So, right-click somewhere in your original clip and select 'Unlink Audio and Video'. Select any other clip (you need to UN-select first) and then click the audio portion of your original clip. You should find that only the audio portion is now selected. Hold your breath and delete it. Yes, delete. Now drag and drop your fixed audio file on the timeline in its' place. Save Project. Done!
November 2005
About Ken
Ken Jarstad is pleasantly retired and living with his wife in the woods of North Mason County in the State of Washington. Ken has worked with electronics for over 45 years, 37 professionally - the last 17 years with PCs. He built his first computer in 1986 and rose from electronics mechanic, repairing and calibrating electronic test equipment, to manager of a network operations center for a 6000 node computer network.
Ken is now the video editor for Power Talk, the weekly cablecast of the Bremerton chapter of the Full Gospel Businessmen's Fellowship International. Besides his own family website, he manages the website for his local port district. He also works a few hours a month for a local doctor's office maintaining a small computer network to meet federal HIPAA security requirements.
