DAT versus dvx audio

L

lurch

Active member
i had a gig last night shooting stand up comics. i linked my camera up with the clubs sound system and the audio clipped horribly,yet it wasnt toping out on the dvx audio meters although it was coming close. is this normal? i was under the impression that it wouldnt clip until the meters topped out

question #2
percentage wise how much more range does DAT handle versus the DVX ? hopefully quite a bit more
 
Re: DAT versus dvx audio

Lurch did you turn off the ALC "Automatic level control" I just did a wireless shoot and couldn't figure out why the sound was acting a little wierd. The ALC was the problem. 8)
 
Re: DAT versus dvx audio

i had a gig last night shooting stand up comics. i linked my camera up with the clubs sound system and the audio clipped horribly,yet it wasnt toping out on the dvx audio meters although it was coming close. is this normal? i was under the impression that it wouldnt clip until the meters topped out
Click to expand...

No, it's not normal. More than likely, the signal you were being fed from the house P/A was too hot. Even though the signal was recorded below 0db on your camera, it was overdriven at the source. Were you monitoring with headphones?

When the sound engineer mixes the audio, he or she is setting levels for optimum sound in the house. In the analog audio world, engineers routinely overdrive the signal hotter than 0db. I've had very little success using a feed from the mixer as my primary audio source.

question #2
percentage wise how much more range does DAT handle versus the DVX ? hopefully quite a bit more
Click to expand...

Digital audio is essentially the same whether you record it on a DAT or your DVX. Anything hotter than 0db is clipped.

MIDIMan
 
Re: DAT versus dvx audio

thanks for the info. Hey Elvis are you sayin the ALC should be on or off? I had it on. I also was not wearin any headphones ,I know how stupid can ya be, but if I was do you think i would have heard the clipping in them?
 
Re: DAT versus dvx audio

[quote author=lurch link=board=Links;num=1080751160;start=0#3 date=03/31/04 at 16:56:36]thanks for the info.    Hey Elvis are you sayin the ALC should be on or off? I had it on. I also was not wearin any headphones ,I know how stupid can ya be, but if I was do you think i would have heard the clipping in them?[/quote]

Yes, you should hear it, and you should have ALC on. It will stop all but the nastiest spikes. I assume you had the inputs set to line level?
 
Re: DAT versus dvx audio

Well I had the ALC on, but I had the inputs set to mic. Would that cause the clipping. THANKS by the way for the quick responses to this. YOU GUYS ROCK
 
Re: DAT versus dvx audio

Hey I found this test of the DVX sound capabilities in DV magazine written be Jay Rose.

http://www.dv.com/features/features_item.jhtml?LookupId=/xml/review/wilt0203

Earlier he had done an artictle about DV cameras (like PD-150 & GL1) couldn't capture the bass or treble sound ranges outside of the human voice range and if you wanted good broadcast/film sound to rely on a DAT recorder for double-system sound . Also they distorted easily, poor sound/noise ratio. But the DVX was a huge improvement and in his opinion/tests.
 
Re: DAT versus dvx audio

[quote author=lurch link=board=Links;num=1080751160;start=0#5 date=03/31/04 at 18:28:31]Well I  had the ALC on, but I had the inputs set to mic. Would that cause the clipping. [/quote]

You betcha! Line level is about 50dB hotter than mic level. That would absolutely blow out your recording....no questions asked.
 
Re: DAT versus dvx audio

[quote author=Elvis link=board=Links;num=1080751160;start=0#1 date=03/31/04 at 08:59:45]Lurch did you turn off the ALC "Automatic level control" I just did a wireless shoot and couldn't figure out why the sound was acting a little wierd. The ALC was the problem.  8)[/quote]

Like Elvis said, ALC can be bad, and it was something we avoided always when shooting ENG/EFP for 10 years, since editors would complain that the people's voices were "breathing", as the threshold compensator on the camera would knock down loud sounds then bring up a high hum level when it was quiet.  At first try to do manual settings, if possible.  Also, as far as I know, DAT records at 96Khz, DV at 48Khz.  I have been told by audio guys that it doesn't step out beyond the normal hearing range of the human ear, it just makes the sampling more accurate and clear.
 
Re: DAT versus dvx audio

Rush, that is what I was having problems with. As far as I know the best way is to shut it off! 8)
 
Re: DAT versus dvx audio

As far as ALC, some cameras (like my VX2000's) seem to experience an artificial boost when the levels are low while using this feature.  With the Panasonic DVX, I find the ALC to basically only affect the signal when hot (ie, compressing/limiting the signal).  If I keep the levels down around -12db, and leave the ALC on, I don't experience the breathing problem.  It's only when having a hot signal where the compression comes into play, that I hear that.

For what it's worth,

Andrew
Crystal Clear Media
 
Re: DAT versus dvx audio

The DVX doesn't even have AGC (automatic gain control), it only has ALC (automatic limiter circuitry). AGC is famous for "pumping" the audio, jacking up the volume during quiet passages, etc. (basically useless in a professional production.)

The DVX doesn't have any sort of auto level setting. What it does have, like Andrew says, is a limiter, which is designed to try to avoid clipping on audio peaks.
 
Re: DAT versus dvx audio

As long as we are talking "sound" on the DVX, is 32k the option/ Is this a result of MiniDv or the DVX?

Any thoughts or clarifications would be great.

FD
 
Re: DAT versus dvx audio

DVX can record 2 channels in 48khz, or two channels in 32khz, leaving two channels available for dubbing. When in 32khz mode, the DV spec provides for four channels total. The DVX camera section can record to two of them, and then when in VCR mode you can dub audio into the other two channels.
 
Re: DAT versus dvx audio

[quote author=Elvis link=board=Links;num=1080751160;start=0#10 date=04/01/04 at 21:29:49]Rush, that is what I was having problems with. As far as I know the best way is to shut it off! 8)[/quote]
Sorry, Elvis, I was backing up your statement, not the other way around.  Didn't quite put that in right (Getting late...) I was just quoting you to illustrate my point. ;D

[quote author=Barry_Green link=board=Links;num=1080751160;start=0#12 date=04/01/04 at 22:18:09]The DVX doesn't even have AGC (automatic gain control), it only has ALC (automatic limiter circuitry).  AGC is famous for "pumping" the audio, jacking up the volume during quiet passages, etc.  (basically useless in a professional production.) The DVX doesn't have any sort of auto level setting.  What it does have, like Andrew says, is a limiter, which is designed to try to avoid clipping on audio peaks.[/quote]
Ahh...  Since I turn off all the auto stuff, I did not know that! Thanks guys.  :)
 
Re: DAT versus dvx audio

Where is the menu function for changing it from 32k to 48k for recording.

Thanks,
FD
 
Re: DAT versus dvx audio

Mine says "16bit," when I bring it into the Avid it always excepts it as 32k.
Any thoughts? Is 16bit = to 48K?

Thanks,
FD
 
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