Applying noise reduction to 'silent' sections

Hi, I’m using OSX 10.7.5 with a recent download of Audacity 2.0.5 using the .dmg installer. I’m new to using the software and have searched around the forum and manuals but cannot find an answer to my question.

I recorded an interview using two two ZoomH1 recorders and two microphones. My mic was handheld and produced a great sound. The person being interviewed wore a lapel mic which was pretty good but I could hear a very slight hum on that recording and her voice seemed to have a slight echo too compared to my voice on the handheld. I would like to remove the hum and echo from the lapel mic recording so that the two voices/tracks are a closer match. I watched a Udemy tutorial that showed how to reduce noise by selecting a ‘silent’ section of the track between vocal sections (i.e. a section that was a slightly thickened straight line), then generating a noise profile and then applying noise reduction to the whole track. When this was done in the tutorial the thickened straight line in the ‘silent’ section became thin indicating that any background hum had been completely removed. But when I apply the same process to my recording the thicker straight lines/sections between vocal sections don’t become any thinner - i.e. the soft hum is not removed. I have tried adjusting the noise reduction settings but this doesn’t seem to change the outcome. I would also like to reduce the slight echo on the lapel recording but can’t find any tools in Audacity that allow you to do this. Any suggestions would be greatly appreciated. PS. I would like to continue to use the lapel mic on the people I am interviewing because it allows for greater flexibility when doing interviews. For example the lady I interviewed is a professional public speaker who is most comfortable and expressive when standing up and on the move - in this instance the lapel mic was perfect for her. Thanks again. :slight_smile:

We can probably help with the hum but probably not with the echo. The echo is, as far as a computer is concerned, the same person’s voice, which make it extremely difficult to remove and echo without also doing a lot of damage to the sound that you want to keep.

That’s the big advantage of lapel mics. You may need to experiment with where exactly you clip the mic. The further away the mic is from the person’s mouth, the more echo and noise it is likely to pick up.

Regarding your current recording, please post a short sample, just 5 or 6 seconds, in WAV format. Ensure that the sample includes some “silence” and some of the speech recording (or post two clips from the same recording session, one with noise and one with speech). See here for how to post audio samples:

Big thanks Steve - your advice is really helpful. I will post a sample for sure. Off to work now so I will tackle it this evening. Thanks again! Much appreciated.