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Sony VX2100 / PD170 / PDX10 Companion
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Old July 25th, 2003, 10:50 PM   #1
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What's the peak audio level?

On the PD150, if I am to manually set the audio gain, what's the maximum should I allow it to be? -20db? I set mine to AGC last time and I got all distorted audio with people screaming in front of me.
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Lucas
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Old July 26th, 2003, 12:40 AM   #2
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peak in DV is 0dB (after that is nasty digital clipping). Canons do things to your audio at -12dB, but I don't think the Sony does. With DV it should be ok to have lots of headroom.

Analog clipping starts at -12db (0db = DV clipping). Analog distorts audio starting at -12db but analog distortion ain't that bad. Rock music uses a lot of analog distortion because the effect is desired.

When the Sony is in AGC mode, it applies a limiter/compressor to really loud sounds so they don't clip. If excessive limiting is applied then things sound really distorted. However, the distortion may have come from your microphone. What mic did you use?
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Old July 26th, 2003, 06:56 AM   #3
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Thanks Glen,

I used an ME-67 with the k6 module (no AA battery loaded in the k6 module).

I saw another post in here recommended to use 50% of the audio meter (that'd be -20db) and the peak is NO MORE than -12db.

http://www.dvinfo.net/conf/showthread.php?s=&threadid=11826&highlight=20db

Mine was also in a wedding reception, by the way.

Thanks in advance,
Lucas
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Old July 26th, 2003, 11:20 AM   #4
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Glen, I think you might have it backwards. In DV peak is -12db and in analouge it's 0db. There really isn't too much headroom with DV at all. At least not with the 150. With the 150 I always run manual whether I have 1 mic or 2 running. I set my level to NO MORE than-12db at PEAK and try to keep my levels to NO MORE than 50% otherwise there could be some bad stuff happening. AAMOF at most wedding receptions regardless of whether it's a DJ or Band I run in MIC ATT, it lowere the gain by 20db and then I can use 50% or slightly less on the levels. So far it's worked fine that way on both my 150's with shotguns.
Of course I do a sound check regardless of how I'm set up, be it shotgun, wireless or plugged into sound board, and make sure of the peaks and levels. Nothing can make the audio good when it's bad to begin with.

In my own opinion, the agc on the 150 is terrible and does nothing but clip and cause problems. But thats just my opinion after using 2 of the 150s for 2+ years.

Don
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Old July 26th, 2003, 11:50 AM   #5
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Interesting.

I've never had clipping inside the 150. Any distortion was caused by the microphone. I regularly record machine gun and heavy (50 cal.) rifle shots, and flash-bangs with my 150. I normally use a Shure SM81 or the Sony microphone that came with my DSR-300.

I run with channel 1 set to about 40% level and channel 2 in auto. Channel 2 does not get into distortion.

If I run a shotgun in a noisy environment, I do get into problems because shotguns are not very good at handling overloads.

I quickly found out that shotguns just don't work for me at weddings. Mainly at the receptions.
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Old July 26th, 2003, 02:16 PM   #6
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Hey Mike,
I know you said before that you've run AGC, I tryed but can't for the life of me get away from the clipping at receptions. I use a shotgun at the wedding ceremony but only for ambient sound.
Oh well, maybe it has something to do with the fact that mine are both old and before the "fix"? Who knows!

The last time I heard a 50 was about 33 years ago, at the time it was the sweetest sound I'd ever heard ;-)

Later,
Don
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Old July 26th, 2003, 06:51 PM   #7
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Hi Lucas,

Have a hunt around for a 10 or even 20dB XLR attenuator for your K6/ME67. The K6 is quite a hot mic and it is probably overloading the frontend of the PD150 when used in a loud situation(like in front of the DJ's PA speakers :) ).

I have a ME66 that I use in conjuction with my DSR-250 and with the 10dB pad in I can get pretty clean audio. If you do use one remember to fit a battery to the K6 as most attenuators won't pass phantom power unless specifically designed to. I usually run the audio in manual with the peaks around the -12dB mark +/- a few dB.

It might also be worthwhile getting a ME62 head for the music side of things so the audio is a little more consistant when your taping side on to the PA and panning around.

regards

Jon
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Old July 27th, 2003, 01:42 PM   #8
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The 50 cal is a sniper rifle. Shakes trees and raises dust for about 6 feet around the rifle. One of the SWAT team members owns it. The PD won't allow him to use it cause it would not only bring down anyone who was shot by it but it'd go through half the buildings in town on the way out. Not to mention shoving the shooter off of anything other than a ground setup.

I just never get clipping unless I get into a loud environment with a shotgun. And I'm convinced it is the shotgun that is distorting because both channels, the manual and the AGC channel have the same amount of distortion.

I think the PD150 AGC acts more like the AGC on my DSR-300. That is, it is truly a pro circuit and unlike the circuit found in my older amateur cameras. Interestingly, my Sony PC110 does very well in AGC mode too. Come to think of it, it has no manual mode. And it does handle gunfire very well. Can't say that the sound of the shot is as well detailed as with the Shure SM81 and the PD150 or DSR-300 but it works OK.
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Old July 27th, 2003, 02:10 PM   #9
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Ahhh, 50 cal sniper :-) I'm familiar with the Army's old M14 sniper weapon, it worked really well, but a 50, WOW. What is the range about a mile? Ahhhhh, the "good old days"

Anyway, I use an ME66 and perhaps thats why AGC just won't work for me. Maybe a "cooler mic". I will tell you that whenever I use the old VX1000 with the audio set to auto, and just the on camera mic, the sound is actually pretty good.
Strange. Oh well, technology for you.
Maybe it's time to try a new mic, although I have to admit, I think I finally got it to a science with the 150 and manual, you know, 'ride the wheel'!

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Old July 27th, 2003, 06:33 PM   #10
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Range is at least a mile if you pay attention to the weather issues.

You might want to ask Sennheiser to add the sensitivity reduction to your K6. It is a standard mod.

Or just put a 20 db attenuator in series with the microphone and see how that does.
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Old July 27th, 2003, 06:47 PM   #11
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Dynamic microphones handle loud sounds better than condenser microphones (most/all shotguns).

A signal that is too hot for your camera will cause distortion, so you will need an attentuator. Regarding attenuators, you can easily build your own attenuator if you know how to solder. Check out articles by Jay Rose at dv.com and under the tutorials at dplay.com. All you have to do is to find the right resistor- you can do this with a variable resistor and then go to a store and buy a smaller resistor (or go to a store and buy all their resistors since they're cents each). MIC ATT also does attenuation. The quality of MIC ATT compared to the normal input differs between cameras (I'd have to check the article on dv.com).

QUOTE:
Glen, I think you might have it backwards. In DV peak is -12db and in analouge it's 0db.

dB is all relative. Most NLEs define 0dB as where DV clipping occurs, so that's what I'm going to go with. In your camera, 0dB is digital clipping and -12dB is where analog clipping starts (i.e. you play a mini-DV tape through it's composite/RCA analog outputs and you record on a VHS VCR).

QUOTE:
There really isn't too much headroom with DV at all. At least not with the 150. With the 150 I always run manual whether I have 1 mic or 2 running. I set my level to NO MORE than-12db at PEAK and try to keep my levels to NO MORE than 50% otherwise there could be some bad stuff happening. AAMOF at most wedding receptions regardless of whether it's a DJ or Band I run in MIC ATT, it lowere the gain by 20db and then I can use 50% or slightly less on the levels.

I meant that you can lower your levels so that you peak at much less than 0dB. In post you can boost the levels. If you are using one microphone, one trick is to record one channel peaking at -12dB and setting the other channel 6dB lower. The other channel serves as a backup.
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