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Old July 20th, 2006, 04:23 PM   #1
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good acustics in a room but not a stong sound in the camra

Due to difficutlies with my wireless system I decided to get the sound from house speaker in a conference I was shooting using a shotgun mic on camera.
I decided to use the auto sound so this way the plauses are not too bad and hopefully a decent sound with cut offline of +6db I beleive.
the sound is ok but when my tv is all way the way up and I am fixing it in post however this is the 2nd time happening to me and If i go a head and use mannual then as soon as the house speaker says something loud or people aplause then the sound distorts. what do u guys do>?
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Old July 21st, 2006, 07:02 AM   #2
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The sound is going to distort if it overloads AT ALL. The mistake you may have made is in setting the limit to +6dB - digital doesn't have any overhead. odB is the point at which sound distorts. You really needed to set a nominal 0dB at -12dB.

+6dB of headroom is an old analogue thing, becuse generally in analogue recording, the level of distortion up to +6dB is acceptable, not so in digital audio.

Also you would have been better getting a line feed from the PA system (though this might have had an effect on your mobility) for channel 1 for the speaker (i.e. the speechmaker) and saved the shotgun on camera for the general for appluase and general atmosphere on channel 2, then you can mix them in post to your heart's content.
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Old July 21st, 2006, 08:23 AM   #3
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What were the difficulties in your wireless system?

One thing you can do is always take along severals short cables that can go into your wireless, each with different connectors on one end: RCA, 1/4 plug, 1/8 plug, XLR-3 male, XLR-3 female, etc. Use a fake balanced in the last two.

In that way you can always plug your transmitter onto any PA system or recording mixer being used in a theater.

Then you can plug that receiver on one channel of your camera. Use your shotgun mic on the other, although a speaker amplified audio will not be much good and should be used only if you have no other option.

The recording levels should be carefully set, and I agree with Dylan there. Though I'd go for -8 or -10dB.

I don't quite get what your TV has to do with the audio. Are you editing this material using the TV speaker as your monitor? You certainly should not.

You should use some audio or video editing program to set your audio levels during editing, and they should never clip. In fact programs such as Sound Forge or those included in Premiere or Vegas can be absolutely accurate on setting levels up or down, and you can edit fade-ups or fade downs in the middle of a track to adjust for "wild" audio.

Beware because some TVs use AGC on their audio circuits, so the audio is always high. Then when there's no audio the hiss or background sound comes up and then is "pumped down" when a louder sound comes in. That's the "pumping effect" you usually associate with bad compression. Rightly applied compression should be inaudible and never let background hiss come up.

Last edited by Carlos E. Martinez; July 21st, 2006 at 09:56 AM.
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Old July 24th, 2006, 05:22 PM   #4
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isnt -6 or -8 really really low>?
I always look at my meters in premiere and try to keep or raise the sound to like -2 or so.
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Old July 25th, 2006, 05:08 AM   #5
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Quote:
Originally Posted by Dan Farzad
isnt -6 or -8 really really low>?
I always look at my meters in premiere and try to keep or raise the sound to like -2 or so.
The meters in Premiere and other NLEs are one thing, the camera's meters are another. It all has to do with meter ballistics and whether it's an averaging VU meter or a peak reading meter. If you send a 0dBu tone through a mixer to the camera inputs or your soundcard inputs when recording in the computer, the theoretical optimum level on the recording meter is -20dBfs to -18dBfs. If your sound doesn't have a lot of peaks you can record hotter -12 or so but be very careful about going about that. The peaks are much higher than the meter is reading but you can't see them because of the meter's characteristics and you want to make sure even the briefest of peaks don't ever go over 0dBfs at all costs.
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