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Adding audio compressor to outdoors audio
Our material is pretty much recorded 100% in the outdoors on Lavs. So when it comes to adding an audio compressor to the tracks in FCP it compresses the voice just fine, but when the talent stops talking the compressor will boost the ambient outdoor noise giving a very unwanted sound.
What are some good techniques for adding compression to “noisy” audio tracks like ours?
“No TV and no beer make Homer something, something…”
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9 Replies
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Well… In tracks where ambience is a real problem, you could send those tracks to SoundTrack Pro to use the noise filter to lower these sounds.
OR… you could just lower the amount of compression. From what you have described to me, it sounds like you’re adding too much compression.
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Wayne Carey
Schazam Productions
http://www.schazamproductions.com
https://blogs.creativecow.net/waynecarey -
Here are several things you can try.
1. Before using the compressor filter, use an expander to lower the noise floor.
2. Try to filter out the background noise with a high pass filter or noise reduction filter.
3. Use better lavs or lav techniques. Good lavs often have better noise rejectionthan cheaper ones (recommend Sanken COS11 or Countryman B6). The closer you mount it to your speaker’s mouth, the higher the signal to noise ratio will be. You can also mount them under clothing to reduce some wind noise, but your speaker may sound muffled, too.
4. Consider using a shotgun mic on a boom, maybe in addition to the lavs. -
[Wayne Carey] “Well… In tracks where ambience is a real problem, you could send those tracks to SoundTrack Pro to use the noise filter to lower these sounds.”
The problem with going to STP is that ALL of our clips ALWAYS have loud ambience. That would add hours to post production. Besides, roundtripping to STP in FCS 1 is a real pain. It seems that FCS2 has solved a lot of these problems, but we just don’t have it yet.
My typical compressor settigns:
Threshold: -20
Ratio: 4
Attack Time: 1
Release Time: 90
Preserve Volume: Checked“No TV and no beer make Homer something, something…”
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Thanks for the suggestions, I’ll try playing with the expander and high pass filters.
[sumfun] “3. Use better lavs or lav techniques. Good lavs often have better noise rejectionthan cheaper ones (recommend Sanken COS11 or Countryman B6)”
I don’t think that noise rejection is the issue here. If my talent is standing by a running outboard motor on a boat on a lake with a swift breeze, when he stops taking the lav will pick up the motor and wind noise reguardless of any kind of built-in noise rejection.
[sumfun] “The closer you mount it to your speaker’s mouth, the higher the signal to noise ratio will be. You can also mount them under clothing to reduce some wind noise, but your speaker may sound muffled, too.”
We allways mount the lav at the 2nd button on their shirt point up towards the mouth (about 8-10 inches away from the mouth). We attach hefty wind screens to the lavs and never place them under clothing because of the muffled sound.
[sumfun] “4. Consider using a shotgun mic on a boom, maybe in addition to the lavs.”
No-can-do. We’re a 1-man-crew operation! I’d love to have an audio tech behind me but a 2 man crew cramming into a 12 foot jon boat just isn’t practicle.
“No TV and no beer make Homer something, something…”
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[Jumpytunes] “My typical compressor settigns:
Threshold: -20
Ratio: 4
Attack Time: 1
Release Time: 90
Preserve Volume: Checked”WOW… That’s heavy compression. I like it alot lighter than that. Here is a copy of my settings. Try this and see how you like it.
Threshold: -40
Ratio: 1.35
Attack time: 5
Release Time: 100
Perserve Volume: UncheckedIf the ambience noise that you talk about is like crickets, then you can EQ them out some. Otherwise, its always best to keep you ambience to a minimum so that you talent doesn’t get drowned out.
_______________________________
Wayne Carey
Schazam Productions
http://www.schazamproductions.com
https://blogs.creativecow.net/waynecarey -
[Jumpytunes] “We attach hefty wind screens to the lavs and never place them under clothing because of the muffled sound.”
We’ve been doing outdoor programming for the past twenty years, and I’ve found that placing the lavs between the layers of the buttons on a shirt is the best location. Its gets a little cover and blocks the wind noise. And placing them at the first button is always the best area for reduced noise.
If your audio seems a little muffled… no problem, just EQ it a touch on the high end to bring it back. I imagine you’ve worked with life vests before. This can be a real problem. The problem you get with hefty wind screens are the the bulkiness of them. Kinda looks like you have a dead rat on your shirt.
The best solution if you can afford it, is to have a sound guy running a boom mic (unidirectional) with a heavy wind sock as close to your talent as possible for best sound.
_______________________________
Wayne Carey
Schazam Productions
http://www.schazamproductions.com
https://blogs.creativecow.net/waynecarey -
Thanks Wayne, I’ll try your settings.
BTW-What exactly does the Preserve Volume box do?
I just check it because without it it really lowers the volume level of the audio. As a matter of procedure, do you increase/decrease your levels before or after you add the compressor? I like to adverage at -12db which usually calls for me to lower my audio track levels by about 10db.
“No TV and no beer make Homer something, something…”
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[Jumpytunes] I don’t think that noise rejection is the issue here. If my talent is standing by a running outboard motor on a boat on a lake with a swift breeze, when he stops taking the lav will pick up the motor and wind noise reguardless of any kind of built-in noise rejection.
Motor noise and wind are two different things. Yes, a good mic will pick up the motor noise, but it will be at a lower level. For example, dynamic mics require more air pressure to move the diaphragm. So it would pick up a nearby (2-8 inches) person well, but is less sensitive to loud noises from farther away. We use these all the time at nightclubs and sporting events. Unfortunately, lavs are condenser, not dynamic. But still the good ones are less sensitive to sounds from far away. Which mic do you use?
Mics need dead air space around them to work well. So you have to shield the wind no matter what type mic you have.
Also, the closer to the speaker, the better. Try the 1st button hole and see if there isn’t a difference. Most lavs are omnidirectional, so they don’t have to point at the speaker.
[Jumpytunes] BTW-What exactly does the Preserve Volume box do?
Preserve volume adds gain to your audio. If your threshold is -20dB and your ratio is 4, then preserve volume will add about 15dB gain. This is because you’re compressing 20dB of sound into 5dB (a reduction factor of 4). To make up for the lower volume, the filter needs to add 15dB gain to get you back to your original level. If your original peak was not at 0dB (which it should never be), then preserve volume might be adding more gain than you want.
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Compressor settings are always going to vary depending on the actual level of each clip. You need to adjust the threshold so that the b/g noise is just below the threshold level. That way when the talent stops talking the noise is not being dragged up.
That said, are you recording with manual levels or auto gain on the camera, because auto gain might be the actual problem, not the compressor.
I don’t know the FCP compressor as I use more serious external units (Penny & Giles PP20 for the audio aficionado’s)but 4:1 on dialog is not heavy depending on how good the compression algorithm is. Use fast attack times. I use .5msec attack and 80msecs release on dialog. Slow attack times means hard attacks are not contained. Conversely fast attack starts to introduce slight distortion.
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