Cleaning up a noisy audio file in audacity?

[BEAD]

I'm trying to transcribe an audio file of some folks having a conversation. It took place outside, and there is quite a bit of noise, as well as a bit of quiet talking, interrupting and such.

 

I'm using audacity.

 

Any tips for reducing noise?

 

I boosted 5k-7k in the FFT filter and dropped the other frequencies, that helped a bit... but I'm going into this without any real knowledge of what I'm doing.

[philbo]

You need a noise reduction plug-in. I don't think Audacity has one built in; at least it didn't the last time I tried it.

 

Download the demo version of Adobe Audition and try using the noise reduction built into that (assuming you are on a WinTel machine - - If you're using a Mac, I don't have any ideas).

[BEAD]

 

Originally posted by philbo You need a noise reduction plug-in. I don't think Audacity has one built in; at least it didn't the last time I tried it. Download the demo version of Adobe Audition and try using the noise reduction built into that (assuming you are on a WinTel machine - - If you're using a Mac, I don't have any ideas).

 

I'm using a pc.

 

Audacity has a noise reduction plugin. It asks me to select a sample of the noise and then select the area I want to remove noise from. I can't seem to keep the voices from sounding like aliens or birds chirping after the noise reduction.

 

I'll download this Adobe Audition and get back to y'all.

 

Thanks.

[BEAD]

The demo of Adobe Audition is a timed trial period affair. I need a longer term solution.

[franknputer]

Try using the VST Enabler for Audacity, and then find a good VST noise reduction plugin. You may have to search to find a good one for free - it's complex technology, and you may end up buying the plugin - but it's probably cheaper than buying Audition. Voxengo, for example, makes a NR plugin that costs $99.

 

Here is a link to start with - there is a free NR plugin here, although it's in French. Still, you might give it a try:

 

http://www.audiomastermind.com/browse-noise_reduction__gates-5887011-1.html

[philbo]

 

Originally posted by chunkathalon I'm using a pc. Audacity has a noise reduction plugin. It asks me to select a sample of the noise and then select the area I want to remove noise from. I can't seem to keep the voices from sounding like aliens or birds chirping after the noise reduction. I'll download this Adobe Audition and get back to y'all. Thanks.

 

 

Sorry, from your post, I thought it was a one-time need.

 

The noise reducer will do that to the sound if you use it too much. For example, if you tell it to reduce noise by 40 dB, you get those chirping artifacts.

 

It's better to do it a little each time.

Start by selecting an area of at least 0.25 seconds with only noise, and use that as your noise sample. (open the noise reducer and pick 'use selection as noise sample' or its equivalent).

 

Now close (not cancel) the noise reducer, and select the entire file, then re-open the noise reducer.

 

If there is an option to preview only the noise, select it. You are now listening to what will be removed.

Now lower the amount of noise reduction till you do not hear any of the voices any more. This is the best setting for the noise reduction.

 

Switch preview back to the denoised signal, preview it, and select apply.

 

 

Repeat a maximum of once, or maybe twice if you are an optimist. More than that and those 'birdie' artifacts will start getting louder.

 

Note that there are limitations to this technology. You will never be able to completely eliminate the noise.

 

This is why recording studios are built with thick soundproofed walls. If they could completely get rid of noise with software, no one would bother doing sound proofing!

[BEAD]

Thanks y'all. I'll give these attempts a run tonight when I get home from school, if I have any energy left. I get home late and get up early.

 

The track is so noisy, the noise reduction plugin that comes with audacity goes straight to bird chirp city on the lowest setting, but maybe a bit of chirping is an acceptable side effect...