Levels levels levels

A

alan b

Active member
File this under the heading of most basic questions possible...

We're doing an interview, I'm watching the VU meter in the DVX window and I'm seeing it go into the red here and there so I kept adjusting so it wouldn't go into the red. Red is bad, I thought...yes I'm new at this, big surprise.

Well I captured some footage, put it into an FCP timeline and I'm looking at the audio track and the waveform is, well, it's there certainly, but it's not what I would think was acceptable levels. Despite my nascent frame of mind, I'm thinking I have to bump the levels up in post.

So what should I be looking for in the VU meter when recording? Is red okay after all?

alan b
 
A little bit of red is okay, yes. The white goes up to only -12db. To get hotter than that you have to go into the red. Each dot represents 2db, so you can have up to four dots of red and still be comfortably below the peaking ceiling. Be sure to turn on ALC so the limiter's engaged.

Would have been nice if Panasonic had designed the level bars with white/yellow/red instead of white/red. Hopefully they'll update that in the HVX.
 
I agree with Barry - you need to get the audio showing about 4 red bars.

My early experience with the DVX also showed the levels were about 6 db low in the NLE if you had the camera levels hovering around the 1st red bar .

When I have Pro audio guys on board they usually come in from their own mixer on the Line input. They are always confused as to exactly what Panasonic used as a reference level. It would be good to know - anyone ? I usually have to lift their gain 3 db+

We normallly safe guard with tracks at two levels anyway.

Did they sort it on the HVX Barry ?
 
Don't know what the HVX will offer yet.

The transition point on the DVX bars is -12db. That's where it turns from white to red.
 
Barry, I'm currently reading Jay Rose's book, and just finished his section on recording to the camera. He emphatically suggests turning ALC *off*. To be honest, that section was getting over my head, and I'm not sure I can paraphrase his arguments for why to turn it off. What are the issues here, and why do you recommend turning it *on*?
 
dr_stupid said:
He emphatically suggests turning ALC *off*. To be honest, that section was getting over my head, and I'm not sure I can paraphrase his arguments for why to turn it off. What are the issues here, and why do you recommend turning it *on*?
Click to expand...

Blame that one on Panasonic's marketing/labeling dept. They call their limiter ACL while auto levels is ALC. You don't want to put the audio on auto but the limiter is helpful in most situations.


Panasonic then made a confusing decision by having the first red being -12dbfs instead of the last white. When setting your levels you should match it at one red bar (2 if you want to push it).

I actually had a camera(wo)man turn the levels on the camera down when I was sending her an average of one to two red bars . I had to keep my cool when I found out but ultimately I blame Panasonic for creating such a confusing meter (for everything else that the DVX does, I have learned to forgive them :))

Glad to see people are reading Jay's book. How's it working for you?
 
Yes, the thing about the acronym ALC is that most camera manufacturers have used it to mean "automatic level control". That is the first thing you'd want to turn *off*. However, the DVX doesn't have any sort of automatic level control (level control is *always* manual), so they instead used the ALC acronym for "automatic limiter control". The ALC on a DVX is a limiter, not an automatic level setter.
 
Why do they use -12db as a reference point. ?

Adobe do the same in their bars and tone in Premiere Pro.

The industry standard is -20db: 1000khz referenced to 0db on the meters.

Its a real trap.
 
Ahh! Thanks for answering my question!

Wabbit, I'm liking Jay's book so far. I think he is trying to target a pretty broad audience as far as level of experience goes, which can be tough, but he does a pretty nice job. I'm a total newbie, so some parts are a little advanced for me, but overall it has been great. Very helpful AND educational (which are not necessarily the same thing, and I like how he incorporates both).
 
Shooter said:
Why do they use -12db as a reference point. ?

Adobe do the same in their bars and tone in Premiere Pro.

The industry standard is -20db: 1000khz referenced to 0db on the meters.

Its a real trap.
Click to expand...

I think many TV stations require the signal to peak at -12dB (some stations use -10dB).

BTW, did you mean to say 1000Hz instead of 1000KHz?
 
dr_stupid said:
Ahh! Thanks for answering my question!

Wabbit, I'm liking Jay's book so far. I think he is trying to target a pretty broad audience as far as level of experience goes, which can be tough, but he does a pretty nice job. I'm a total newbie, so some parts are a little advanced for me, but overall it has been great. Very helpful AND educational (which are not necessarily the same thing, and I like how he incorporates both).
Click to expand...

Great to hear. Pay it forward :) (recommend it to others). I picked up a copy several years ago after talking with Jay and even though I had been mixing for years I learned quite a bit. Honestly it should be bundled with with ENG microphones the way Barry's book is bundled with the DVX.

The whole -20dbfs is the aquisition standard for professional level equipment. For prosumer type equipment -12dbfs has become the standard. It gets more dynamic range with prosumer level equipment but threatens blowouts more often.

For output levels there are several standards depending on what format you are outputing to.

Hope that clears things up.
 
Jay Rose's book is the best. Actually, books - they overlap a bit, but complement one another well. I was an audio engineer in Boston during the 70s and 80s, and Jay had already earned his reputation as a knowledgeable and pragmatic engineer. A girlfriend of mine worked for him at his downtown studio. He was (and seems to still be) nice to boot!

You are right - his books both have much useful info for novice and pro alike.
 
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