Using Goldwave to clarify speech in background noise

Sometimes a clip with vital speech on it is affected by continuous background noise from machinery, or mains hum, for example. I learned from David Jackson how to use the program "Goldwave" to lessen its effect, but hopefully not to change the speech quality too much. The procedure is:

1) Import the .wav file or digital video file.

2) Play sound to identify a stretch of background noise only, without speech as the example below;-

3) Highlight this stretch of background noise only.

4) Press Control + C to copy it to the clipboard.

5) Select the highlighted section of the soundtrack.

6) Click on Effects > Filters > Noise Reduction.

7) Select "Clipboard" and "% Reduction  (try 50% to start with).

8) Click "OK" (Goldwave will deduct the selected percentage of background noise from the highlighted section.)

9) Play the highlighted section. (If OK, press "Control + Z" to undo the test reduction, and press "Control + A" to select the whole file.)

10) Click on Effects > Filters > Noise Reduction.

11) Select "Clipboard" and "% Reduction" (as chosen).

12) Click "OK" (Goldwave will deduct the selected percentage of background noise from the whole file).

13) Play the whole file, and if the speech quality is still OK, Export by Saving. If not OK, Press "Control + Z" to undo the noise reduction, and return to Step 3 again to try a different percentage of noise reduction.

(David recommends trying a small percentage (say 20 - 25%) first, and seeing if the background noise is diminished sufficiently without spoiling the speech quality too much. If it is not sufficiently diminished, then go back to Step 3 and proceed again with another small increase of percentage, until you are happy with the final result.)

The cleaned up waveform is below showing no sound in the silence and much less fuzz between the words indicated by the waveform bubbles.

Mac users will need to use a different key for "Control" [Apple key] wherever it occurs above, the text was written for PC users.
 
 
 
 

by Sir Paul Holden