Eliminating room sound from a field recording

Posted: Thu Mar 27, 2008 8:07 am

I'm using a field recording of speech that was recorded in a very bright lively room. There's a lot of this room sound on the recording and wonder if anyone has some recommendations for getting rid of some of that room sound and retaining a pretty "natural" sound. In other words, I'm trying to make a very "roomy" recording sound deader.
Thanks.
Blacklab

Posted: Thu Mar 27, 2008 9:43 am

You're going to have a hard time. You could try using a gate and or some downward expansion. I doubt that it will sound natural in any way though. Maybe there is a magic tool out there. I don't know.

Posted: Thu Mar 27, 2008 10:07 am

I'm just thinking out loud, but is it possible to take a sample of the room noise, then add it to another track and flip it around so it phases out?

I apologize in advance if that's a moronic notion. I'll quietly go back in my room, but at least slide a pancake under the door for me.

Posted: Thu Mar 27, 2008 11:03 am

Not moronic but still, I doubt this would sound natural in any way. Any time you employ phase reversal as noise reduction it's going to affect tone. Depending on how loud the noise is, it could potentially sound really odd. From mild chorusing to blatant dropouts in the dialogue.

Posted: Thu Mar 27, 2008 11:14 am

Not only that, you'd have to have an exact duplicate of the reverb emitted from the original presentation only phase reversed but minus the original impulse. Sounds tricky to me...

Posted: Thu Mar 27, 2008 12:33 pm

Sorry Blacklab - I don't meant to hijack the thread and ask more questions, but I'd like to know just in case something like this pops up while I'm working on something.

So sampling the room is pretty much out of the question. Would it be safe to assume that a good noise reduction unit/plug-in would help with this situation?

Posted: Thu Mar 27, 2008 1:05 pm

No.

Broadband noise reduction will not help with reducing impulses from a recording. If it were constant hum or some other similar non-correlated audio signal, yes. However, with a signal that generates impulses (voice and echo), trying to remove this with NR tools will sound absurd and silly.

Of course, I'm operating on the assumption that your room sound is referring to the echo you mention due to a very "lively" room.

Posted: Thu Mar 27, 2008 4:52 pm

I had to deal with this on a few occasions.

Here is one of the ways I was able to improve this.

DBX made a multiband downward expander for dynamic range enhancement of other overly squashed material. It was called the 3BX. It would exaggerate the dynamic range too much and I would then throw a limiter (broadband 1176) on top of that. It would greatly reduce the reverberation. But I believe you can still accomplish that in software provided you also frequency weight it?

I think the best that you can expect is only a slight reduction?
Ms. Remy Ann David

Posted: Fri Mar 28, 2008 6:45 pm

I had some room noise that wouldn't go away. I recorded the room noise and reversed the phase relationship, and it went away. However, any slight modification to the room noise recording made the phase inversion fail. I used to EQ it out manually, but that didn't work out so well last few times. Good Luck.
On another note, I don't mind a good sounding recording with room noise. It adds intimacy to some guitar and light vocal tracks.

Posted: Fri Mar 28, 2008 10:18 pm

Dolby Cat43, or a Cedar DNS1000.

These are noise reduction boxes, fortunately their side effect is reverb tail taming!!!!

Posted: Tue Apr 01, 2008 10:50 am

Thanks all, for the information. Here's the story of the recording...I had a chance to interview some elusive characters and had to do it in a very bouncy room with no chance of close-miking. So...I got great interviews with a LOT of room reverb. Very good sound quality, but a lot of verb. Yes, even a LITTLE reduction of that room sound would be great. I've tried sampling the room and removing that sound and, you're all right, it sounds ridiculous. I guess what I was hoping for was a "magic plugin"...the Cedar plugin is a little out of my range, but I got some good ideas from you all. I'll let you know...
Again, very good input and I really appreciate it!
Blacklab

Posted: Tue Apr 01, 2008 12:39 pm

Add background music. Loud background music.

Posted: Mon Apr 28, 2008 8:30 pm

look into the Roger Nichols Digital Dynamizer plugin. I've used it to remove reverb from some sources in downward expansion mode. It's a bizzare item, takes a lot of getting used to, but an interesting tool.

Posted: Mon Apr 28, 2008 8:47 pm

Quote:

guess what I was hoping for was a "magic plugin"...the Cedar plugin is a little out of my range, but I got some good ideas from you all. I'll let you know...

There is no magic plugin, actually there still are no plugins that can match
a Dolby CAT43 or DNS1000, rent one they are cheap.

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