indoor audio nat sound reduction

J

jdh3334

Active member
We shot a scene in a computer lab where the air-conditioner blasted noise the whole time.

The dialogue level sounds okay, but, can I reduce the ambient machine sound?

We can't go back to reshoot. The actors are gone.

Sooooo. What, if anything, can I do in Final Cut Pro HD to reduce the background noise without losing the dialogue?

Thanks,
Jeff
 
I assume you have tried to EQ the sound out with a tight notch filter? A lot of the time AC hum is very constant, so try isolate the source by enhancing with the EQ, and then pull it out. Also, try rolling off the lows (up to like 100Hz), that may or may not help.

I dunno if PTHD has them, but try a sampling noise reduction tool like the ones in Cool Edit (now Adobe Audition)...
 
soundtrack pro has good tools for doing this- much like what's in audition. you just give it a sample of the noise alone, sans dialogue, and it then attenuates that frequency range as much as you want it to. the more drastically you filter the given frequency, the more it tends to mess with the sound of the dialogue.

a little semantics note: when you hear the term "AC hum," (as in the noise removal filter in fcp,) they're not talking about air conditioners but alternating current. (which is 60 hz in america.) so if you open the noise removal filter in fcp, don't get all excitted when you see the "ac hum" preset. your "ac hum" is a different beast.

but a high-pass filter is a good place to start, as timapter suggested. (well, he suggested eq, but if you just want to eliminate everything below a given freq, a hi pass filter is the easiest way to do it.) try a high pass set to around 100 hz and see how much that helps. the higher you set the cutoff, the more it will adversely effect the dialogue.

btw, for future reference, unplug evrything in the room that isn't directly related to your production. screw em if they're hot.
 
You must log in or register to reply here.
Back
Top