Audio for RAW

Steve Kahn

Steve Kahn

Well-known member
As many of you know the 5D3 is now capable of raw video but currently incapable of sound recording.

The camera is capable of sending out a trigger - via a beep or wired sound which could trigger an audio recorder.

Anyone have any good recommendations on a good digital recording unit that can be triggered to start and stop?

This would be a great asset to the RAW video community and would really help matching up sound to video in post - both files initiated with the same time stamp, both the same duration.

Thanks!
 
Mmm, why not have your sound person start and stop the audio recorder, and use a simple slate to sync your audio and video rather than trying to reinvent the wheel? By the way, your audio and video will not have the same time stamp as you put it, unless you were to use both audio and video recorders capable of time code sync.
 
The files would both have the same time stamp, not timecode. They would also be the same time duration. This would save a lot of confusion in matching audio and video files in post.

David W. Jones said:
Mmm, why not have your sound person start and stop the audio recorder, and use a simple slate to sync your audio and video rather than trying to reinvent the wheel?
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That wheel was invented 80 years ago. I think it's time to reinvent it.
 
Steve Kahn said:
The files would both have the same time stamp, not timecode. They would also be the same time duration. This would save a lot of confusion in matching audio and video files in post.


That wheel was invented 80 years ago. I think it's time to reinvent it.
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Nope sorry, wrong on both accounts. The wheel was not invented 80 years ago, and your files will not have the same time stamp.
 
Steve Kahn said:
The files would both have the same time stamp, not timecode. They would also be the same time duration. This would save a lot of confusion in matching audio and video files in post.
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Not reliably. Sure, you can set the date and time for each device and they'll have roughly the same metadata for when the file was created, but there are also sound recorders out there that use an automated scene/take file naming scheme (Fostex FR2-LE, for example) which make tracking audio takes much, much easier.

Plus, there may be a slight delay between starts and stops between the camera and recorder with this trigger system. You still won't have perfect sync.

Steve Kahn said:
That wheel was invented 80 years ago. I think it's time to reinvent it.
Click to expand...

There's a reason the slate is still around. It is, hands-down, the fastest and easiest way to mark takes between picture and sound for later reference. Even on sets with TC sync to the sound recorder, a slate is still used. Why? Time Code won't necessarily make your life easier, but having the scene and take number clearly audible on the sound file and clearly visible in the picture, along with an instantaneous sync mark (the clap), will guarantee a match.
 
Fostex DC-R302
Automatic syncing through IR or wired for single button operation of both units.
Slate tone.
Parallel tracks on camera and in recorder.

Still need to visual slate though for perfect syncing with the image, but gets you mostly there.

After that there is the Zaxcomm Maxx, which is a mixer/recorder with built in visual/sound slate.
 
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Your welcome. The Fostex is exactly my solution for 5DMarkIII RAW audio issue. On sale by the way at B&H right now at $250 less than anywhere else.
 
Steve Kahn said:
The files would both have the same time stamp, not timecode. They would also be the same time duration. This would save a lot of confusion in matching audio and video files in post.


That wheel was invented 80 years ago. I think it's time to reinvent it.
Click to expand...
They would ABOUT the same time-stamp, not the same time-stamp, because there is no way to synchronize the system clocks in both the camera and the audio recorder to the within 1/30 of a second of each other accuracy that would be required for the time-stamps in the two file headers to be identical. The simplest way to prevent confusion in post is to use a visual slate at the start of picture to unambiguously identify the take and at the same time call it out within earshot of the mic, coupled with a written shot log to keep track of false starts, etc.
 
Steve Kahn said:
That wheel was invented 80 years ago. I think it's time to reinvent it.
Click to expand...

Now the interesting thing about that quote is that the actual wheel was invented a lot longer ago than that and guess what... we are still using it. Your car runs on four of them and with only minor improvements over the original.

So while new is sometimes good and sometimes MUCH better than old, sometimes they got it right a long time ago.

Any remote start and stop will have a lag. You still need to slate, unless your an idiot, so there is not a lot of benefit to the automation. Unless you are not using a sound person to monitor things and then you have other issues that will outweigh the lack of slate. Like the lack of sound you actually want to use.

But drop me a line because for $75 an hour I will try to salvage what you have.
 
Steve Kahn said:
So is automatic syncing of the Fostex and 5D3 a viable solution?
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Since I have only be peripherally involved in 'broadcast', as I understand it... in order to have all your equipment 'sync'd' you need a timing signal for all equipment to be connected to, which then provides the 'syncing'.

Any time one has 'free running' oscillators, the basic circuit for timing anything, there will be drift between the two or more clocks. When the 'sync' signal is distributed, each device 'adjusts' their local clock to match the sync signal.

I don't know if the 5d3 has the ability to take in an external sync signal, or produce one which would then be fed into the audio recording device.

As it is, the 'clapper board' acts as the sync signal, and if the shots are 'short' there will be minimal drift with modern circuits, and so the audio and video can be 'easily' aligned.

Part of the procedure involves having the person with the clapper call out the shot, so it is on the audio and the slate shows the visual version of the shot info.

These days, one could perhaps get equipment that has GPS devices attached, which can with just one satellite lock, receive a precision timing sync signal... but that would not work well for indoors, although cell phone towers also transmit timing, and could be used for better syncing over time, if a number of recording devices are being used, and there is a need for accurate assembly of the sync'd result.

But for the one camera one audio recorder setup that's probably not really available... but who knows someone may have a 'cheap' solution.

Since for my short films, all shots are under 10-15 seconds, where dialog is captured, (more like 2-5 seconds for 'dialog'...), I have no problem with the 'old fashioned' method of dual sound, using the slate clapper to mark the shot and then in my NLE aligning the audio with the video.

My use of a modern 'innovation' is to have the camera 'audio' available as a reference track, and with Premiere, I am able to get fine resolution on adjusting the second sound's sync with the 'reference track'... and verify that they both match up with the video.
 
When I asked about viability I am not necessarily meaning are the two signals in sync.

1. Can the camera reliably start audio recording?

2. Can the camera reliably stop audio recording?

3. If there is a time lag between the two is that consistent?
 
To get two devices to stay truly in sync you need two things. First you need an accurate (as in subframe accurate) positional reference. Actual time code can do that. Then you need to sync the timing of the two devices. In analog you could use something like Pilot-tone or even TC subframe's but for digital you need Word Clock or an equivalent. All the devices that can generate and receive both are med pricey to very pricey. anything less and you are doing a high tech version of a clapper and you are going to have to phase in the production with out the benefit of a clapper.

the only cheap system that I know of that really works is to set up both devices clocks to "the same time" and use a clapper.

The time stamp will get you close and tell you which clips go together and the clapper will set you sync.

IF you can send the same TC to each device then you can get the start time to sync in a NLE but you will still have drift.

A slate is the epitome of the KISS principal. It's dead simple, very cheap, and always works. You can spend a lot to make a complicated setup that works pretty well but why? If you spend the big bucks and have tri level sync everywhere then you have something, but we are talking $$$.
 
Again - I did not say or insinuate eliminating the clapper but do find it advantageous if a camera could initiate and stop sound.

More - if the time lag between the two was consistent single button control would greatly speed matching up tracks in post.

Finally, time stamps of video and audio, even close, would simplify knowing which audio track goes with with video (I've worked with sound guys that let the sound run between takes. In post in this case things can quickly turn quite confusing)
 
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I was referring to a different post.

So yes the time stamps will be close if you set both devices clocks the same (but has nothing to do with this feature, that will always be true).

No the time lag will not be consistent, but it will probably be close.

The sound mixer not stopping between takes is a people problem not an equipment problem. EVERYONE on a film works for the director and or producer. I'm neither so it's not for my self I'm saying that. So talk to your crew and get the plan and workflow worked out. The only reason the mixer would not stop between takes is that they were not told you wanted that. Or they were not the person to be doing your sound. There are folks, editors, sound folks, cinematographers, that forget that their job is not primarily to do "their art" but to do their art to SUPPORT the directors vision. Those people you just need to fire, ASAP.

It's a team sport but there is a captain of the team.

So if you din't go over the workflow before you started and make sure everyone knew what needed to happen give yourself a stern talking to and don't do that again.

If you did go over the workflow and your sound guy went off the reservation then boot his butt out. Or be nice and give him another chance but make SURE he or she knows that it's YOUR film and they need to stick with the workflow.

You need the guy with the cans on monitoring your sound and they should also be controlling the equipment. They NEED to be responsible and you can't take the power away and expect them to be responsible, you just showed you don't trust them.

So while this thing would probably work most of the time, it's a connection and it could go wrong. You won't know unless someone is monitoring and how close are they going to be watching something they are not allowed to touch? And if you can't trust them to push the buttons why are they on your set??? They wouldn't be on mine.
 
Steve Kahn said:
Again - I did not say or insinuate eliminating the clapper but do find it advantageous if a camera could initiate and stop sound.

More - if the time lag between the two was consistent single button control would greatly speed matching up tracks in post.

Finally, time stamps of video and audio, even close, would simplify knowing which audio track goes with with video (I've worked with sound guys that let the sound run between takes. In post in this case things can quickly turn quite confusing)
Click to expand...

What it sounds like with this description of your idea is you need a 'gang start' button. I don't believe the 5d3 has such for 'external equipment'... however a quick check of the Internet suggests there are apps which are available on some platform which allow for 'remote control' of the 5d3, and perhaps there are similar apps for some piece of audio equipment... of course that would be two apps... and of course you'd want one app that would gang start both devices (or all devices if multiple cameras and audio recorders were involved...).

These days WIFI is taking over areas that Bluetooth formerly was popular, but I don't know if there is a 'low end' audio recorder with WIFI/Bluetooth controls, and from that basis, whether there's an app... etc.
 
j1clark@ucsd.edu said:
What it sounds like with this description of your idea is you need a 'gang start' button. I don't believe the 5d3 has such for 'external equipment'... however a quick check of the Internet suggests there are apps which are available on some platform which allow for 'remote control' of the 5d3, and perhaps there are similar apps for some piece of audio equipment... of course that would be two apps... and of course you'd want one app that would gang start both devices (or all devices if multiple cameras and audio recorders were involved...).

These days WIFI is taking over areas that Bluetooth formerly was popular, but I don't know if there is a 'low end' audio recorder with WIFI/Bluetooth controls, and from that basis, whether there's an app... etc.
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The Fostex DC-R302 has exactly that, call it a "gang start" or what ever you chose. Start either the reccorder or the camera and the other starts as well. This either happens through the infrared eye of the 5D Mark III or through a wired connection. This is the only recorder I know that does this.
 
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