Machine Shop Die grinder

I have 4 DVD videos, with sporatic Die Grinder noise in the background.
Does anyone have recommendations for Noise Reduction setting, Sensitivity setting, Frequency smoothing, and Attack/decay time.

I’m new to this aspect of Audacity, and don’t really understand how to select?

I it just a matter of trial and error?


How hard would it be to shoot that again without the grinder? If the grinder winds up and slows down during the interview, it is now a performer in the show. We can’t split performances up into individual instruments, voices, or grinders.

Your first task is to split the sound tracks from your DVDs – assuming they’re “Movie DVDs” and not just shiny hard drives (Data DVD).

Then you need to let the filter “sniff” the bad sound by selecting some of the grinder by itself. No voices or other sounds. The tool will try to delete whatever you selected in that sample (Profile).

Then select the whole show or a large portion in the case of a very long show, and apply the filter. Start with a modest reduction of 12dB and see what happens to the show. ‘Smoothing’ affects how much of the spoken word gets missed by the reduction. ‘Attack and release’ affects the amount before and after a word gets missed. ‘Sensitivity’ is the magic one. If you get a reduction that’s almost right, try increasing that a little and see if it helps.

The tool will reduce the selected sound and destroy the show. The object is to get the first before the second. If there is no balance, then you may need to select each grinder sound and noise reduce them individually. If you were using a camcorder, it’s very possible that there is no voice back there to rescue. You get rid of the grinder and the voice is trash.



Thanks for the reply.

These were training videos from 20 years ago.

VCR tapes converted to DVD’s and then copied to a hard drive.

So, I have them in multiple formats.

I will print off and read your reply offline.


Does the grinder start up and slow down? Then you’re dead. You’re also dead if you can’t ever get a clean grinder sound for use as a profile. Koz