Audio levels -12db?

[Joe Riggs]

This is a semi continuation of my recent posts.

The hits just keep coming; let's talk levels for a moment. I'm going to be talking to production tonight and want to make sure I have my facts straight and I'm not talking out of my behind. I've gone through the audio for the first couple days and the levels are pretty low around -42 to -30db and occasionally peaking around -24db. This is occurring for both the boom and lavs. Shouldn't the levels be around -12db?

I'm not just talking about Wide shots where the boom can't be near the actors either, the same thing is happening in Mediums and O/S, and it's not framed in some artistic way, the players heads are near the top of the frame, so the boom mic if placed properly should be giving a pretty strong signal and I imagine the lavs should be as well.

The boom mic, sounds okay when boosting the signal, but clearly with the boost, noise is being added. The lav on the other hand sounds pretty bad with a boosted signal.

 

[Marc Wielage]

It depends on the mics and preamps involved. I tend to bump up the mix track pretty loud and use a limiter on it, since this is what the editor and director will see and hear in dailies, averaging at around -10dBfs. I don't have a problem hitting -3dBfs or so on a very loud scream or gunshot. The other tracks have much more conservative levels, typically lower by at least 5-6 dB. This is assuming digital peak-reading meters. -24dBfs is incredibly low.

Cheap mixers, cheap mics, and cheap preamps will result in noise when you crank them up. This is why great mixers, great mics, and great preamps are costly. Using good gain staging optimizes the signal flow across the project, so that at no point is the level too low or too high. Experienced location mixers know the vast techniques involved in getting these details right.

 

[Robert Hart]

My personal preference is to try to sit in the -12db to -15db range. I would rather sacrifice some perspective in recording than suffer unintelligible dialogue which is buried in an armpit and overboosted to recover it. Digital audio when dragged up from the deepest depths can have an uncomforting sound, gritty or whatever. I simply don't like it. If there is a risk dialogue will distort or clip, then my personal preference is to bracket the levels in two separate audio tracks so that a composite can be satisfactorily constructed out of two tracks. Please do not pay particular heed to my comments as I am far from qualified to advise.

 

[Joel Arvidsson]

My personal preference is to try to sit in the -12db to -15db range. I would rather sacrifice some perspective in recording than suffer unintelligible dialogue which is buried in an armpit and overboosted to recover it. Digital audio when dragged up from the deepest depths can have an uncomforting sound, gritty or whatever. I simply don't like it. If there is a risk dialogue will distort or clip, then my personal preference is to bracket the levels in two separate audio tracks so that a composite can be satisfactorily constructed out of two tracks. Please do not pay particular heed to my comments as I am far from qualified to advise.

Anyone found a way to do internal audio channel bracketing?

 

[Michael Dalton]

Anyone found a way to do internal audio channel bracketing?

This is something I'd love for Red to include in the next built, the ability to remap audio channels. If I'm shooting a single mic, I'd love to have the ability to stagger the levels by feeding the mono channel into both mic channels 1&2. I'd set the first slightly lower, and second one a little hotter. That way I'm covered.

 

[Mike P.]

This is something I'd love for Red to include in the next built, the ability to remap audio channels. If I'm shooting a single mic, I'd love to have the ability to stagger the levels by feeding the mono channel into both mic channels 1&2. I'd set the first slightly lower, and second one a little hotter. That way I'm covered.

Can you not do this physically -- have the mic connected to a 3.5mm splitter (dual mono) and then feeding the same mic into Mic1 and Mic2 inputs, each with different gain settings to capture higher and lower audio… If I'm understanding you correctly, I'm fairly certain that would fit the bill.

 

[Dustin Dooley]

You could possibly do this with a passive mic but with active mics you can run into problems. If you are using a battery in your mic you probably won't run into an issue as you would not be using the cams 48v phantom power and the mic will typically have a resistor to prevent the current from going back to the input. This also helps lengthen the battery life. On the other hand, if you are using a simple wire splitter and you supply the phantom power from the cam you are essentially backwashing the input not supplying the phantom voltage with power it wasn't expecting. Depending on whether the cam or recorder has resistors built in to combat that scenario, you most likely won't fry the cam, but it can introduce some pretty wicked hum depending on how the circuitry handles it. In that case the best scenario is to get a direct box and make sure the phantom is provided on the NON transformer side of the split or get a field mixer that provides phantom to split the signal. you can also get active direct boxes that will provide phantom power that have two outputs.