Attached is a couple seconds from a file I’ve received for my gamer podcast. I have tried to remove the noise, but when I do you can hear at buzz at every syllable. I’ve tried using the sliders in Noise Removal in a wide variety of combinations, all to no avail, but I’m hoping someone might know of a way.
I am using the latest version of Audacity on Windows 7 Professional x64 SP1.
The last settings I tried were:
Noise reduction: 48
Sensitivity: 0
Frequency smoothing: 1000
Attack/decay: .15
But like I said, I’ve previewed it at various combinations and it pretty much always sounds the same.
That sample has so many problems it’s hard to know where to start …
The level is way too low. Try Effect > Amplify, accept the defaults and click OK
You can now see that the file has DC offset (the waves are not centered on the center line).
Now do Effect > Normalize, accept the defaults and click OK
That got rid of the DC offset. Now listen to the clip …
It has really bad hum, and the signal (the voice) is barely above the hum. It also has very low level random tones behind it, as if someone has already tried to do noise reduction, or there is some sort of interference.
To get rid of the hum, do Effect > Notch Filter, set Frequency to 60 and Q to 10. Then do it again with a frequency of 120, and again with a frequency of 180.
That’s got rid of most of the hum. You could continue to apply the Notch Filter with increasing frequencies at multiples of 60 (240, 300, 360, 420, 480) but the more you do this the more you damage the signal.
Select from 0.2 to 0.7 seconds, do Effect > Noise Removal and Get Noise Profile
Select the whole clip, do Effect > Noise Removal with Noise Reduction 24, Sensitivity 0, Frequency Smoothing 150, and Attack/Decay 0.15.
That’s about as good as it’s going to get.
Thank you, Bill! I will follow your instructions tomorrow and see how it pans out. I didn’t even know about the DC offset and stuff, still ignorant about things like that as of yet. I mean, I know what it is, but I wouldn’t know to check or how to check or that it was important to check, lol. Exactly the type of help I needed! I’ll let you know how it goes. Hopefully from here on out I won’t be having any of these issues with the 'cast, but I’d like to get this one at least bearable
She thinks she may have had two mics on at once. I don’t understand why it was so clear on Skype but her recording was so awful.
I’ve also given them all the link to that recording usb device, so thanks for that, Koz.
Feel free to move this to the podcast forum if you wish.
This turned out much better than I’d hoped for. I will have to learn about the Notch Filter, I’ve never used it before. Thank you so much for your help, you’ve saved this podcast episode!
