Article on noise reduction that might help.

Sony's Noise Reduction is among the very best. On the cheap side, sometimes Pinnacle's "Cleen" can work reasonably well.

For this sort of task, the Noise Reduction app will work wonders, since it sounds (ha!) like the unwanted noise will be very localized to a particular frequency band. This means that the Noise Reduction effect will be to put a "hole" of user-selectable depth right at that location on the frequency graph, leaving the rest of the spectrum untouched.

For other applications, such as background noise in a crowded hall, I've concluded that NR is a two-sided sword--true, it can cut out background stuff, but in so doing it also hacks away any musical subtleties and overtones. In other words, a chorus singing in a concert hall definitely sounds different after applying NR. So you have to be careful.

You guys are amazing! I will immerse myself in task of noise-reduction suggestions and report back on the outcome of this particular project.

An aside -- I will never again agree to record in an unsuitable venue just because the client says "it's just fine' ---they have no clue as to the (unsatisfactory) results and what it entails to correct.
Thank you again.
Lili

While the suggestions for trying the NR (or other plugin) may indeed tackle the problem nicely, you might first want to try fixing it in Vegas. I’ve gotten quite acceptable results with the exact situation you are describing using only the audio tools included in Vegas; especially when the VO has been recorded separately and can be dealt with on its own track(s).

JL

I also had to do some background noise removal for some interviews that had continuious background noise and the noise reduction plugin, while expensive, worked absolutely perfectly.

riredale,
You are right about the chorus loosing some in the noise reduction. It is a give and take. In such situations (particularly) one needs to use NR several times, in smaller steps. Just remember to take a new sample each time.

JL,
If you have NR (or something like it) you would probably use that first every time. If you don't, I agree, you can get results using Vegas. Like the stacked filters in paragraphic EQ. For complex noise use NR. It costs much less than a retake.

Lili
Yes, some clients will expect you to do the impossible simply because they do not know how hard it is. That is why so many film- and videomakers are doing so many impossible things. They do not know beforehand which jump will take them higher and which will break their neck.
Tor

One of the biggest challenges with the NR tool is getting a clean sample of what you don't want. If your samples contain anything that you need to keep you're going to have problems, someone talking quietly in the background will do you over for sure.
Here's a few tips:
1) The size of the sample needs to match the frquency range you're trying to remove. If for example you're trying to get rid of some hum then a really small sample will not provide anough data to the internal analyser to see the hum, enlarge the aread you're taking the sample from both vertically and horizontally so you get a clear look at what you're sampling.
2) Sometimes I get better results by not using NR, if there's a bit of room tone and a hum there's no way to get a clean sample of the hum without the broad spectrum room tone and the result will play havoc with almost anything I don't want to touch.
So I use the Spectrum Analysis in SF to look at a section of silence. From that you can isolate the objectionable frequencies and then use a surgical Eq to get rid of them.
What would be nice is if Sony did a bit more work on the NR2 tool, it's nigh impossible to manually modify the captured noise print spectrum as there's no way to zoom in on the thing, unless I've overlooked the bleeding obvious (again).
Bob.

I use BIAS Sound Soap 2 and it works great and it simple to use. Not as robust as Sony NR but not nearly as expensive either. It gets the job done for things like background hum, AC, etc. quite well.

~jr

If itis precisely a 60 Hz centered hum without too much higher harmonics, you can try a steep high pass filter at 80-90 Hz and a noise gate.

A high cut filter at about 10 kHz can also help to tame room garbage.

Audacity comes with a decent selection of built-in processors, including a simple but effective multiband noise reducer, and it can also serve as a host for filters, processors, and utilities in a variety of formats. Some of these plug-ins are at the Audacity Web site; there are plenty of others at www.kvr-vst.com and www.mda-vst.com. (The latter is advertiser supported, and the graphics on this home page take you to commercial stuff. But the text link at the top of the page takes you to a treasure trove of free plug-ins.)

Best of all, it's free!

John

Jay Rose wrote another good article on Noise Reduction in 2003. Sign up at DV.com then come back and click on the link to read the article.

The sad thing is, if you actually can salvage it, you prove the client right. It IS "Fine."