Killing background noise (without the possibility of ADR)

[Xerolux]

I'm in a sticky situation.
I filmed a wedding a while back and am in the process of editing and audio mixing.
The challenge I have is the ceremony was held outside on a patio of a converted castle.
Well, during the ceremony all of the industrial-grade HVAC units kick on and now there's a huge, turbulent fan noise which almost masks the wedding vows and ceremony.

The bride, groom and officiant weren't mic'd so all I have to go on is one channel of audio on the camera (Panasonic HVX-200A) and the second channel is a Rode shotgun mic (on camera). I know the mistake was not having them all lav'd but there's no going back now.

I was thinking of sampling the noise during a "quiet moment" of the ceremony, and inverting its phase, then mixing it back in with the main track to cancel out the HVAC noise hopefully, without any degradation to the voices.

NLE is FCP, DAW is Logic Pro.

Any thoughts or easier fixes? Plug-ins, (yeah right)?

Thanks,

-Damien

 

[mkfotos.com]

From everything I've read recently, Izotope RX 2 might be worth looking into.

 

[gpforet]

Constant tone and pattern noise like a/c noise is something that I've had quite a bit of success getting rid of using Izotope RX. Still takes some work and I tend to work in the spectragraph tool, you by learning how to use the tool, and committing some time, you should be able to reduce the sound of the a/c without affecting the dialog too much. Of course, it's still going to sound like the dialog was recorded at a distance, and all the other non-pattern sounds will still be there (but can be systematically removed using Izotope).

 

[Xerolux]

Great,

Thank you both for the suggestions. I'll check out the software.