What effects or alterations should I consider for clarity of audio in my video?

Question

I should start out by saying I know just about nothing about audio. I have Audacity, and I've used it for the most basic things like trimming and combining audio clips.

I have a video that consists of one person talking, with some audience noise.

Are there any filters, effects, alterations, or anything else that I can do in Audacity that I should be considering in order to get the best sound possible? I mean any kind of alterations at all, like changing levels, altering pitch, improving clarity... anything.

I don't expect miracles, I just hope to achieve a little more clarity and accentuation if possible.

Please keep in mind I know no sound editing terminology, so if you could explain using specific filter names, or let me know what things mean in simple terms, that would help immensely.

Also, if it matters, the sound is from a video file, recorded off a high definition camera. I think it's stereo, but it's just the one track.

Answer 1

I've never had much luck removing such things completely, however it's generally possible to improve it with some equalization. Ambient noise, particularly humming or buzzing sounds are often most-annoying at a small frequency range, so it's possible to filter that range out using a notch filter. Generally you can't "magically" get rid of the problem, but you can de-emphasize it a bit.

The top of this frequency chart shows male and female vocal ranges. This will mostly apply to speaking voices. Clarity and sibilance ("s" sounds) appear to be most present around 2-6KHz, so you may try emphasizing those a bit while de-emphasizing around them. Of course, this won't work if your noise is also in the same range.

I've never tried this, but in theory it would be possible to sidechain a gate effect limited to that frequency range against the sound level in another frequency range where there isn't as much noise, so that the frequencies are filtered out except when the person is speaking. However, you'd have to have a toolset with a feature like that. I'm pretty sure you can't do that in Audacity, but I've never tried. I think something like that might be possible with an environment with more routing options, such as REAPER.

Izotope makes a product called RX that does surprisingly good noise removal, but it's probably a bit more expensive than you're interested in if you just want to boost clarity a bit.