"There is background noise in my studio. Should I use a noise-reduction plug-in?"
A question from an Audio Masterclass student...
"I have a question about noise suppressors. Is a noise suppressor really worth the money because of signal loss during the process, and if so, which one of these would you recommend?"
There is a balance to be struck here between being a purist and being a pragmatist. But suppose you had an important project and hired a top studio at a rate of $2000 a day, which is what top studios do charge. They tell you that there's some building work going on outside, but they have a noise-reduction plug-in so it will be OK. Well unless that was the only studio in town and the work absolutely had to be done there, there's no way I would even consider this.
Professionally, the standard is to record in a well-insulated studio where noise isn't a problem. But suppose you record at home and noise is a problem. Will a noise reduction plug-in solve it?
There is no doubt that modern noise reduction software can be useful. But this is where the purist in me asks the question, "What's the point of recording to 24-bit/96 kHz resolution, then messing about with it?". As someone who remembers the horrendous noise level of analog tape, being able to achieve 24/96 resolution is like achieving Nirvana.
Call me old-fashioned if you like, but I doubt if I will ever come to believe that using a noise-reduction plug-in can ever be as good, or as right, as recording with a quiet noise background. No matter how far the technology advances, it will always have to choose between what is noise and what is wanted signal. And I just can't see how it can do that to an accuracy of 1 part in 16,777,216, which is the resolution of a 24-bit recording, less a small margin for dither.
And you have to consider where you should concentrate your attention. Optimizing the settings on even a simple noise-reduction plug-in takes a lot of care and attention. But if you're working with a quiet noise background, then during recording you can devote yourself fully to your performer and the sound coming from the microphone, safe in the knowledge that during editing and mixing, you won't be distracted by the artefacts that noise-reduction plug-ins inevitably create.
But there are exceptions. If you are given a recording to work with that has background noise, then you'll either have to put up with the noise, or use noise-reduction software. Which you choose depends on the preferences of your client or your market.
Or you might have had to record in a noisy environment. An example of this would be an interview with a celebrity of some kind, done out of necessity on location rather than in a studio.
Another scenario is audio for film or TV. Often the needs of the picture come before the needs of the sound. So the director might have called 'cut and print' on a take that was visually perfect, but sonically deficient. Too bad. The sound department is going to have to clean it up somehow.
So in summary, my personal view is that the standard to aim for is to record with a quiet background noise level. That's the way professional studios work. They are the people you'll be competing with, and you'll be competing on the quality of your work, not the quality of your excuses.
But if you really have to. If you really, really have to, then modern noise-reduction software can do a remarkable job.
One more thing... the question asked for a recommendation. Well I've tried a number of noise reduction softwares and my experience is that they are all different. Sometimes very different, sometimes subtly different. One might work better on speech than on instruments, another might handle constant background noise better, another works well for impulsive noise. Comparing demo versions on your own actual problem is the way to choose.