dual sound necessary if no back up required?

[TheDingo]

Non-defeatable AGC negates any benefits of uncompressed audio

I would some what agree with this statement, but in this case we are getting 66 dB of dynamic range with the GH3 camera minus the 3 dB AGC ( if it activates ), so the recorded dynamic range is 63-66 dB that is stored in an uncompressed format. This is almost identical to the audio recorded by a Panasonic HMC-150/HPX-170 cameras, which show a dynamic range of 63 dB. ( not great, but definitely workable )

Okay, so you're lowering the input gain to minimize the effects of the AGC. That gain still has to be made up somewhere. It can be made up by pumping a hotter signal into the camera, which is common, and that risks overmodulating the input as I have previously stated.

Yes, feeding a distorted/overmodulated signal is always a recipe for disaster, but feeding a clean/controlled signal that works well with you camera settings, can give you quite a good result with no overmodulation or signal clipping, and a workable amount of headroom.

Here's an audio sample recorded directly into my Panasonic GH2 camera that I recorded "blindly" as I had no means of monitoring the audio input at the time, but I used camera and Sennheiser G3 settings that I knew would produce good results in this sort of situation. ( I had shot with this combo more than a dozen times, when I shot this interview ) For this type of work, the in-camera audio was definitely good enough for the final video.

Ronnie Burkett Interview ( first 2 minutes is GH2 audio, the remaining audio is an Olympus LS-11 recorder sitting 12 feet below the puppeteer because I could not mic him directly )

The gain can also be made up after the fact, whether there is a secondary level control in-camera or it is simply brought up in post, in which case noise floor is increased with the signal. The former can work, tenuously, but leaves little wiggle room. The latter increases noise.

The recorded signal was recorded at exactly the level I wanted, with no distortion, and with a potential noise-floor of -63 dB RMS. ( the ambient noise in the theater was likely much higher than -63 dB RMS ) I think I had about 10 dB of head-room with this set-up, before the GH2 limiter would start "flattening" stronger audio signals.

The Panasonic GH3 has improved the audio over the GH2, but still has the damned AGC circuitry. I am really hoping the GH4 has the ability to kill off the AGC component completely. ( probably wishful thinking, but one can always hope )

 

[Richard Crowley]

http://www.usa.canon.com/cusa/professional/standard_display/cinema-firmware-1dc

The EOS-1D C now accepts a line-level audio input via its mini 3.5mm connector, for users who want to use an optional outboard mixing console, for example, or a high-output microphone. In Line Input mode the standard input level is -8 dBV* with peaks up to +6 dBV. To accommodate different external sources, sound-recording levels are adjustable at 64 step levels

That looks like a hardware update to me. You said it was "firmware". That remains impossible. If the input connector is hard-wired (via the PC board) to a mic preamp, there is NO WAY to bypass that unless they designed in the HARDWARE to switch the audio around the preamp. Of course their marketing people insulate us from the engineers who designed it, and the marketing gerbs assume we are all idiots and don't understand technical language (because they don't themselves). The chances of getting an accurate and authoritative explanation about this appear somewhere between slim and none.

 

[Andrius Simutis]

I do believe that sums up my lowering the bar nicely. IF you don't care about the sound you can do anything. IF you do then any time saved by not syncing is lost when post tries to make it usable.

Again, I know you're an audio guy so don't take offense when people adjust the amount of effort they are willing or able to take in audio acquisition. Sometimes you have to compromise, and sometimes the compromise isn't even enough to be noticed.

I probably was not clear enough with "any film with a budget". Any film that has a full paid crew and is going through the workflow for distribution...

…so you mean a big budget, not a small budget. Got it. I don't think we're talking about a hollywood movie or even a TV show just slapping a Rode Videomic on a DSLR and calling it done. I thought you were replying to my mention of snowboarding, and that's something I do know, so that's how it is. Some of those movies have decent budgets and still don't do post audio sfx and just use the on camera audio.

Also shooting double system and doing post sound are not at all connected.

The point was that anything more than on camera audio requires some work in post. SFX and foley aren't always a replacement for capturing audio in the field, and capturing that audio via dual system isn't always a viable option.

Aaaaaaaanyway…I think we agree that with a budget and time it's a better idea to record dual system sound. No debate there. I'd even go so far as to say you should hire a dedicated audio professional with top level gear and lots of experience. My only real point was that it's just not always possible within the budget or time constraints to do it so you should look at what you can really get away with and how good you can make it with what's available. Not to make everything sound like crap. But forget that, let's just argue it some more like we're imagining that we're diametrically opposed on this. It is teh internets after all.

 

[Noiz2]

…so you mean a big budget, not a small budget. Got it. I don't think we're talking about a hollywood movie or even a TV show just slapping a Rode Videomic on a DSLR and calling it done. I thought you were replying to my mention of snowboarding, and that's something I do know, so that's how it is. Some of those movies have decent budgets and still don't do post audio sfx and just use the on camera audio.

NO certainly not BIG budget. If paying your whole crew equals big budget then...?

Any non "reality" TV show is shooting dual, and actually only the "in the wild" RTV shows might be shooting with only camera audio.
And all of them are going through audio post.

Low budget "Hollywood" style is around $30 mill and under. Low budget for distribution is more like under $5 mill. Someplace under a few hundred K your heading into the "no budget" range and you don't really have much if any chance of distribution unless it's self distribution. I like to call these the MiniIndie's.

Any film over say $50k that is not doing a real audio post is crazy. Even the no budget poster child "EL Mariachi" did a full sound post (actually three).

I have done a fair number of MiniIndie's and I will use whatever sounds are usable from production. Most of that would normally be Foley (it's always capitalized BTW). But in a narrative film you are just plain stupid if you don't do sound post.

The core reason is that your film did not take place in the world of YOUR film set. So pretty much everything you recorded is wrong for the "world" of your story. Sound post lets you create the WORLD that the story takes place in. Pictures can't do that. You know your world much more by what it sounds like than what it looks like. That in part is why actually silent films never worked and radio thrived for decades here and is still strong in many parts of the world. In practice the "silent" films were filled with FX and music and in some countries people speaking the lines.

People aften talk about the Cra*& sound of low budget films. But the sound is not particularly "bad" (sometimes it is) but the filmmaker failed to create a "world" for their story and what people noticed was the lack of sounds. Sometimes people don't even connect it with the sound they just don't like the film. But in many cases it's not so much the film being bad as no "set" for the show. It takes really great acting to pull off a show with no sets.

We are disagreeing on a side street though. The OP question was "why". So even if I say everything you said was 100% true the reason people go double with DSLR's is quality. They may not go double because that quality is out balanced by other factors but Quality is still the reason folks are saying to go double.

 

[TheDingo]

..."the reason people go double with DSLR's is quality. They may not go double because that quality is out balanced by other factors but Quality is still the reason folks are saying to go double."

+1 Pretty much says it all.

 

[Andrius Simutis]

NO certainly not BIG budget. If paying your whole crew equals big budget then...?
Any non "reality" TV show is shooting dual, and actually only the "in the wild" RTV shows might be shooting with only camera audio.
And all of them are going through audio post…
Low budget "Hollywood" style is around $30 mill and under. Low budget for distribution is more like under $5 mill...

Ok, I get where you're coming from, you just weren't considering news, sports, or documentary and that's more where I'm thinking. Sure, dramas will need that audio created more than a docu or news piece would. Did we ever find out what the OP was shooting?

We are disagreeing on a side street though.

Couldn't agree more.

 

[TheDingo]

Did we ever find out what the OP was shooting?

"vocals recorded for interviews" is what the OP stated in his original message.

 

[Andrius Simutis]

"vocals recorded for interviews" is what the OP stated in his original message.

Ok, then we'll need a six person location audio team with a Nagra, top of the line mics, six months to do post audio and a budget of five million…kidding. Just kidding.