Audio-post processing on dialogue in wilderness footage

[cybrmarc]

Hello,
I work for a wilderness school and we are making youtube videos and video accompaniments to our books. Much of what we do is taping people sitting in a circle and talking, or standing around and putting on/FAQ'ing a workshop.

We have a lot of footage already stored, and much of it is pretty rough to work with. There are mosquitos (some flying right by the mic - LOUD!), birds, a crackling fire, and who knows what else mucking up the dialogue. I thought I could get away from learning how to manipulate frequencies and do noise reduction by synchronizing our external voice recorder, but - alas, in some instances it does not make a difference.

So far I'm been looking for a program with a good live-action spectrum-meter so I can learn what freq. the different noises are at (e.g. insects versus birds versus plane overhead versus different human voices). WaveLab and Audacity both have decent meters it seems. I should add, I work at a small non-profit, and investing (time and or money) in getting the big Adobe Products (like Audition) like overkill.

My big question is: is it really feasible to reduce or eliminate nature sounds for an amateur such as myself? My perception so far is that most automated noise removers just pick up a frequency set (like the hum of electricity or the camera hardware) and ditch that. But what about things with varying frequencies like insects or bird songs? Will there be too many artifacts to keep track of? Should I just post-amplify the hell out of it and try to get rid of the resultant post-amplified hardware noise?

Thanks,
Marcus

 

[slashbinslashbash]

I'm no audio expert, but IMO the best thing that you could do is set up multiple microphones.

AFAIK, professional audio/video taping where "realism" doesn't matter (i.e. a show where cameras are acknowledged) relies very heavily on individual lapel mics for each person. Tapings of movies/shows that are more "acted" (pretend the camera isn't there) rely on highly directional boom mics positioned right in front of the person's face, just out of the camera frame.

If mic'ing up everybody individually is too much expense, I think you could make some headway by getting 1 or 2 more microphones and distributing them evenly throughout the area. You could do some cancellation between the mics for sound that is uniformly distributed (bugs, planes overhead), and only one mic at a time would ever be affected by something like a mosquito. Overall it will still be a lot of processing work, but at least you will have more source to work with.

It would be good to have a choice of several directional mics available for use depending on the situation.

Across-the-board spectrum analysis is never going to work. Too many of the sounds overlap. Birds, bugs, and planes all can have frequency overlap with human voices. It might be feasible in certain circumstances.

 

[cybrmarc]

So if across the board frequency deletion doesn't work, what about:

1. Identify the frequency of the offending noise (like a cicada which is mostly at 8,000-10,000) and at least lower that, in each individual section (cicada goes for 10 seconds and then stops, then restore normal freq level). Is this only going to be possible with stuff way off the normal voice frequency, because otherwise it'll dull out the voice? Would this make it really obvious that frequency was lowered and then re-normalized?

2. Post-amplify the heck out of everything. And then simply lower the volume on other non-voice sections, and deal with the akward sudden rise when the voice comes in?

 

[slashbinslashbash]

I think it will be pretty obvious that the sound has been messed with, but give it a shot. At this point, it's a matter of "what can we live with?"