AC Noise
- Thread starter Sherman
- Start date
Getting rid of A/C noise is very difficult, if it can be accomplished at all without seriously compromising the sound you want to keep.
The best way of dealing with comes back to how you record it. You should eliminate as much background noise as you can, including turning off the A/C.
But, if you CAN'T turn it off, you should record room tone -- a recording of the room with everyone staying absolutely quiet -- for about the duration of the scene. Then, you can use it to even out the dialogue you recorded. That is, if some lines have the A/C noise and some don't, you can use the room tone to put under the lines that don't.
Also, keeping the microphone as close as possible will alleviate a lot of the problem.
In post, you have some options, but they're all band-aids and not viable fixes. You can use the Noise Gate (click on the green cross on the audio track), but you'll affect the sounds you want to keep -- and it will be worse the closer the A/C volume is compared to the voice volume. You can use the Equalizer to eliminate the frequencies of the A/C, but you'll also be eliminating frequencies in the voices.
There's noise-reduction software, but cheap/free software will butcher your dialog. There's expensive software, like Sony's noise reduction package, but that'll set you back about $200 and there's no guarantee you'll get satisfactory results.
I would have liked to have been able to say "sure, just use X effect," but unfortunately, there's no easy fix.
The best way of dealing with comes back to how you record it. You should eliminate as much background noise as you can, including turning off the A/C.
But, if you CAN'T turn it off, you should record room tone -- a recording of the room with everyone staying absolutely quiet -- for about the duration of the scene. Then, you can use it to even out the dialogue you recorded. That is, if some lines have the A/C noise and some don't, you can use the room tone to put under the lines that don't.
Also, keeping the microphone as close as possible will alleviate a lot of the problem.
In post, you have some options, but they're all band-aids and not viable fixes. You can use the Noise Gate (click on the green cross on the audio track), but you'll affect the sounds you want to keep -- and it will be worse the closer the A/C volume is compared to the voice volume. You can use the Equalizer to eliminate the frequencies of the A/C, but you'll also be eliminating frequencies in the voices.
There's noise-reduction software, but cheap/free software will butcher your dialog. There's expensive software, like Sony's noise reduction package, but that'll set you back about $200 and there's no guarantee you'll get satisfactory results.
I would have liked to have been able to say "sure, just use X effect," but unfortunately, there's no easy fix.
I would take a look at iZotope RX (there is a free trial). It is an outstanding audio restoration tool which borders on Voodoo magic (it can fix problems we use to tell people were impossible to fix). If you can't afford that, BIAS Sound Soap does a good job of removing broadband noise like A/C. As David said, Sony Noise Reduction is good but newer tool like iZotope RX are in a whole class above it and IMHO should be in everyone kit who does on-location audio. I use RX all the time to fix the unpredictable.
~jr
~jr
Robert Eldon
Well-known member
SoundSoap from Bias has worked pretty well for us... in a pinch.
