Problem with sound recording

[Fostire]

Does anyone here know how I can edit out some background noise from a sound recording?

My problem is as follows: I was in charge of recording the sound for a documentary/interview film thing and I found in post-production that one of the recordings has a lot of noise from the rain.
Now I need to figure out if there is a way to edit out the rain while keeping the voice. I don't care about any other background sounds, just the voice.
Can it be done?

[Kindablue]

You can attempt to remove the noise with Audacity (http://audacity.sourceforge.net/) (which is free) by following this guide (http://wiki.audacityteam.org/index.php?title=Noise_Removal). Your success may vary, though, depending on the recording itself.

[Jimorian]

That's a tough one. There are a lot of video/audio software that have various methods of decreasing noise like that. Rain is going to be fairly close to "white noise" for your purposes. I know for example that Final Cut has it, and the PC program I use for video editing, MAGIX Movie Edit Pro, also has it.

The standard technique is to find a section where the person isn't talking and ALL you hear is the rain, point the software to that segment for a sample, then it will try to "subtract" that sound from the entire clip. There will usually be a parameter you can set for how hard it tries. You usually have to settle for just eliminating part of it, otherwise the sound you want left alone starts to acquire a weird mechanical/robot quality to it that's more distracting than the background noise.

I haven't looked, but I'm guessing that the function that Kindablue is talking about in Audacity is this type of thing.

My advice is that unless this is the kind of thing where you're cutting between different recordings and it goes on/off because of it, you're better off leaving it as atmosphere. The other solution if you're using cuts is to go the OTHER way and add a rain sample to the clean recordings so that it at least sounds even (or perhaps do a bit of both and meet somewhere in the middle).

This technique is used in films where on set or location, one of the things the audio guy does is record 2 or 3 minutes of "silence" in the room for the post-production audio guy to lay down as a background track to scenes from that location. There is an amazing amount of stuff going on it a "quiet" place that you never notice until it's oddly not there in a too-clean recording of the actors speaking.

[Fostire]

I haven't looked, but I'm guessing that the function that Kindablue is talking about in Audacity is this type of thing.
Yeah, it looks like it.


My advice is that unless this is the kind of thing where you're cutting between different recordings and it goes on/off because of it, you're better off leaving it as atmosphere.
I would leave it as atmosphere but the problem is that it's kind of loud and it's a bit hard to hear what the person is saying.

Thanks for the suggestions, I'm going to try audacity and hope it works.

[thubby]

failing audacity working, a parametric equalizer might be able to do it.

provided the speaker's voice and the rain aren't in the same frequency range, anyway.

[missmvicious]

Since you've gotten advice on how to cut the noise you've got, here's a tip on preventing the noise in the first place... for future reference:

Have a look at the type of mic you're using, then hit up the music shops around town and start asking for unidirectional microphones. They can be a bit invasive during an interview, but they're designed to ignore ambient noise. Despite what you may think, you don't always get what you pay for here. My husband owned a recording studio in the early part of the millennium and the cheapest mic he used was an Electro Voice unidirectional mic, by several hundred dollars. I asked him why he skimped on the vocal mic; he said he didn't. It was the best mic for the job. He did his research, found it was the one most local radio DJs and public speakers used. It seemed to be a great vocal mic. And it was. He played me some of his stuff and the vocals, usually so underpowered in independent recording studios, sounded surprisingly bold and clear.

I'm not sure if the interview in question was outdoors (under shelter) or indoors, but here is a link to some recording advice for all occasions that I found with a quick google search that seemed to make some really valid points.

http://airmedia.org/PageInfo.php?PageID=199

My Husband's 2CP:
If recording indoors, try to find a "dead room." Do a test recording before interviewing to see how much ambience is "humming" in the background before starting the interview. You may be surprised at how much noise we've become accustomed to. If you have the luxury of picking your own location, pick your space wisely. Rooms with windows, large air vents, excessive electronics, etc are bad mojo for recordings. Get a room that is open (no clutter) and soft, which is to say, carpeted or with proper acoustical walls so you don't have weird echo effects, and so that you're not amplifying unwanted air conditioner noise, rustling, walking, or whatever else is going on in there.

[Fostire]

Audacity's noise removal tool worked quite nicely. It removed the more constant part of the noise but there was some none constant wind that I couldn't remove. Luckily most of it was in "quiet" parts so it can be edited out but some of it got in the way of the noise so we'll have to see if it can be used.


Since you've gotten advice on how to cut the noise you've got, here's a tip on preventing the noise in the first place... for future reference:

Have a look at the type of mic you're using, then hit up the music shops around town and start asking for unidirectional microphones. They can be a bit invasive during an interview, but they're designed to ignore ambient noise. Despite what you may think, you don't always get what you pay for here. My husband owned a recording studio in the early part of the millennium and the cheapest mic he used was an Electro Voice unidirectional mic, by several hundred dollars. I asked him why he skimped on the vocal mic; he said he didn't. It was the best mic for the job. He did his research, found it was the one most local radio DJs and public speakers used. It seemed to be a great vocal mic. And it was. He played me some of his stuff and the vocals, usually so underpowered in independent recording studios, sounded surprisingly bold and clear.

I'm not sure if the interview in question was outdoors (under shelter) or indoors, but here is a link to some recording advice for all occasions that I found with a quick google search that seemed to make some really valid points.

http://airmedia.org/PageInfo.php?PageID=199

My Husband's 2CP:
If recording indoors, try to find a "dead room." Do a test recording before interviewing to see how much ambience is "humming" in the background before starting the interview. You may be surprised at how much noise we've become accustomed to. If you have the luxury of picking your own location, pick your space wisely. Rooms with windows, large air vents, excessive electronics, etc are bad mojo for recordings. Get a room that is open (no clutter) and soft, which is to say, carpeted or with proper acoustical walls so you don't have weird echo effects, and so that you're not amplifying unwanted air conditioner noise, rustling, walking, or whatever else is going on in there.

Thanks for the advise :smallsmile:
We actually did a test recording but I swear I didn't hear the rain then.
As for the equipment, this is part of a school project so we had to use the school's equipment but I'll keep your advise in mind for future non-school projects.