How do you handle audio clipping? at DVinfo.net

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Old February 2nd, 2006, 10:26 AM   #1
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How do you handle audio clipping?

When doing events where there is a mic stand where people give speeches, sing, or whatever, I attach my wireless sennheiser handheld mic to the mic stand as a second mic to record audio straight to my camera. With that said, I had a person singing a song and I was monitoring the audio. Then the person starting singing a lot louder and closer to the mic and it wasn't really clipping per say but it wasn't clean sounding either. How do you adjust for this situation? Should I just record at a lower level and adjust it up in post? If I do this, then I'll probably raise the noise level too.

Thanks,
Eric
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Old February 2nd, 2006, 10:30 AM   #2
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If you can, a strategy is to use two mics and record one mic on each channel in the camera. Set one to record at about -6 to -12 db average level and the other at about -18db. Now you have insurance in case a sudden burst of volume clips one channel you've got the other good track as a backup with which to replace the bad audio.
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Old February 2nd, 2006, 12:43 PM   #3
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If you haven't already done so, you should familiarize yourself with the transmitter gain functions of your wireless.

It's very easy to overload the transmitter preamp (yes, it has one!) in this situation - you need to adjust it for the loudest sound you expect. Doing a pre-event sound check with a singer is a good thing. No amount of tweakage at the camera or in post can fix clipping that comes from the transmitter.

Then you do also need to be monitoring for record levels. Following Steve's suggestion, above, some cameras have switching so that you can send audio input 1 to channels 1 & 2, with manual control. Setting Ch. 2 as Steve outlined.

A little mixer can also accomplish this, splitting the mic signal.

Or as above, 2 mics.
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Old February 2nd, 2006, 02:42 PM   #4
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I use a single mic and split it into 2 channels (cheap adaptor - radio shack)...I then balance the audio to one side (basically the same thing as using 2 mics, but with some signal loss from splitting the signal out). Try to adjust the sound as loud as you can/think it will get, with the balance to the side (50-60% to one side) you have your safety track for editing.
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Old February 2nd, 2006, 03:55 PM   #5
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Quote:
Originally Posted by Eric Holloway
When doing events where there is a mic stand where people give speeches, sing, or whatever, I attach my wireless sennheiser handheld mic to the mic stand as a second mic to record audio straight to my camera. With that said, I had a person singing a song and I was monitoring the audio. Then the person starting singing a lot louder and closer to the mic and it wasn't really clipping per say but it wasn't clean sounding either. How do you adjust for this situation? Should I just record at a lower level and adjust it up in post? If I do this, then I'll probably raise the noise level too.

Thanks,
Eric
You were clipping somwhere. If not at the camera, then at the mic, xmitter or receiver. Gain staging is very important. You might have been OK if you had backed off the input trim on the transmitter. Sometimes that just happens and you're stuck with wireless.

If you're hard-wired and have someone doing audio, they can catch that sort of stuff at the mixer.

Regards,

Ty Ford
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Old February 2nd, 2006, 04:12 PM   #6
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You're up against one of the basic problems of sound recording--welcome to the club.
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Old February 2nd, 2006, 04:15 PM   #7
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Quote:
Originally Posted by Fred Retread
You're up against one of the basic problems of sound recording--welcome to the club.
Thanks for the welcome party! LOL
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Old February 3rd, 2006, 08:31 PM   #8
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Just curious... I see next-to-no discussion of using limiters or compressors on the DV boards. Having a hard compressor in-line is certainly going to sound unnatural. But some soft-knee compression, with a threshold set to just kick in when it gets hot... is (a) something that can be done with some subtlety and (b) sure sounds better than clipping!

On a shoot with a dedicated sound guy and pro gear, is any sort of limiting every used? Enquiring minds...
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Old February 4th, 2006, 06:19 AM   #9
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All of the pro gear has some sort of limiter. Good location audio gear has fairly fast limiters that are kind to the audio. That's pretty much all you need.

The limiters in Sound Devices mixers are some off the best. I own the Sound Devices 442 mixer and have reviewed the MixPre and 302. All three sound really good and have good limiters. The 442 has a limiter on each input and a pair across the output busses. The limiters are quite transparent.

Regards,

Ty Ford
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