Removing hollow room sound

8string

8string

Well-known member
Had to shoot some stuff in a room that had a bit of 'hollow' or 'echo' like sound to it. Sort of like shooting in an empty room with lots of hard surfaces. What's the easiest way to get the sound somewhat cleaned up, given that it's unlikely to be totally cleaned up..
 
Oh man, I don't know, but if you figure it out let me know. It is a pain. I have had to trash some irreplaceable footage because of echo before. Not fun. I did a google search and could not find any consensus on how it it done. Sorry.
 
Unfortunately, there isn't much you can do. Selective use of compressors, expanders, and EQ can help, but only to a point.

This is where we usually recommend the "Reshoot" filter. Of course, that's rarely practical or even logistically possible.
 
A trick is to use eq to put a notch in at between 200 - 300Hz. I usually find around 240Hz does for a start.

It's not perfect, but it can get rid of some of the "boominess".
 
If you know Logic or Soundtrack Pro, you may be able to compress and invert the phase on a copy of the audio file. Mix together to cause phase cancellation to remove some of the echo. I have seen it work successfully before. A member here did it for me and it did make a difference, I still had to reshoot anyway, but if the audio was the only problem, then I would have kept it.

Try posting this in the Audio section, you never know what you could come up with.
 
thx folks. I know that it's a problem that's hard, if not impossible to solve, and have no choice to reshoot, as the content is compelling enough, so I'll try the notch, compress and invert to play around with it. That gives me a start, so I appreciate it. I think given my audience I'll be able to let it ride, but it's a lesson worth noting, that I had no clean room to interview these folks in, and had to do the best we could.
 
BTW - compressed fiberglass and sound blankets do wonders in a room that needs some tightening. I made a few 2x4 panels of 2" compressed fiberglass by wrapping them in black canvas. The CFG helps tighten the low end especially if used near the corners. Sound blankets draped over C-stands can lower the reverberation time.

These solutions will not, however, fix transmission problems such as loud noises coming from another room or through a door/window.


jason
 
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