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Old February 5th, 2004, 01:11 AM   #1
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The Great Debate: Direct-to-Camera vs. DAT

We've got a huge discussion going on in pre-production... and I'd love to get expert thoughts on this. The great debate:

Does recording into a DAT machine *significantly* improve the audio quality in order to justify the expense (no budget filmmaking) and required time (for sync, etc.) in post?

What I know about the equipment available: Sony PD-150, an excellent supercardioid mic, boom, two wireless mics, a good mixer (not sure on the type), headphones. We would need to rent all DAT related equipment...

thanks!
Stephanie
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Old February 5th, 2004, 02:06 AM   #2
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At least in one way it would improve audio quality: You need (or should have) an extra person to operate the DAT. That in itself would improve things at least as a precausion against unexpected audio problems.
Otherwise, you'd be using the same equipment, same mixer etc. So the quality of whatever hits the tape will be the same.
Syncing is a breeze, at least in Vegas (which I use). All in all: an extra sound person is good, the DAT in itself won't make much of a difference.
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Old February 5th, 2004, 05:23 AM   #3
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I have put a link in another forum, which is of interest for you:
http://www.sounddevices.com/tech/pd150.htm




NB.: This is a very nice mixer:
http://www.noyzboyz.nl/
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Old February 5th, 2004, 08:45 AM   #4
 
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Tor is correct in regards tohaving an extra person, but nothing beats the extra set of hands no matter what they're doing.
In terms of audio, the camera and the dat machine are equal. Unless you have an older dat that can't do 48K, in which case the camera is better. Unless you have a newer dat that can do 24/48k in which case the dat is slightly better.
You will still do better with camera audio in long shoots, because the clock will be slightly skewed no matter what. This only becomes a problem on long shoots where there are no edits. Anything longer than about 15 minutes will have drift, it becomes fairly visible around 25 mins or so. If you are editing of course, this is no issue at all.

Jan's link shows a site relating to the PD 150, which is known as a poor audio option in most any event, but it does also show that the DAC's are better in some cams than others, while most DAT machines are fairly consistent. With most cams, ALWAYS defeat the Auto-Gain Control when inputting external audio supplies. Monitor from the camera, and you will *generally* be satisfied with dialog and background music applications. If you are looking for the dynamic range of a DAT, you *probably* aren't going to capture that quality at a live shoot, let alone as a solo act on a shoot.
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Old February 5th, 2004, 09:16 AM   #5
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I'll throw my 2 cents in with regards to the original post.
My answer is it "can" significantly increase your audio quality.
There are lots of variables here, including the audio quality of the SPECIFIC PD-150 you happen to have and the amount of time you can dedicate to post-production.
Obviously the DAT deck you happen to get is also a factor, but as already stated, this is fairly consistent especially if you're feeding it line-level signals from a mixer with good preamps.
Other things to consider are what style of project is this?
Syncing isn't a major problem, but keeping tight control on the relationship between all your media bits can be.
In other words, can you actually find that 2 seconds you need from the DAT tape to match with that reaction shot from Take-15 of scene-12, camera angle-4, where the director said "Do it again" 3 times without re-slating it? That's an extreme example, but you get the idea. Your project may not even be oriented towards generating so many small segments in the finished project either, but if it is, then you should really dedicate an additional person to keeping careful logs of what gets recorded.
Some benefits of an external recorder: As already stated, having someone to specifically control and monitor the deck is of great benefit. Not being tethered to the camera for action sequences can be beneficial, but in static situations you should still send the same signal to both the camera and external recorder by wired connections. Even with an external recorder it is critical to still get the best possible audio into the camera.
One drawback of DAT: Do you have the means to capture the tape digitally into your editor? If you don't, this isn't as big a deal as it is with mini-disc, but you can still have a reduction in quality by going analog. Also, DAT takes real time to capture and at this level won't have timecode for recapturing in sync later if something gets lost.
You may want to consider renting a different format of external recorder such as a Marantz flash-card recorder. It's more reliable, faster to capture and can be more easily backed up to CD-R or DVD-R.
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Old February 5th, 2004, 09:24 AM   #6
 
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One thing worth looking into is the Nnovia box, as it's got ANALOG ins to a hard disk recorder. http://www.nnovia.com for more info. The converters are very good, and it can act as a deck only. Then it's just another firewire drive to your computer later on. It also has a heirarchy for bins, etc. It fits on a belt, has a battery pack, and 80 gigs of diskspace. One thing I've not tested for is if it can see JUST audio vs audio and a video stream.
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Old February 5th, 2004, 09:53 AM   #7
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Re: The Great Debate: Direct-to-Camera vs. DAT

<<<-- Does recording into a DAT machine *significantly* improve the audio quality in order to justify the expense (no budget filmmaking) and required time (for sync, etc.) in post?>>>

You'll get different views. Mine would be spit your signals
and use both the camera
and a DAT. DAT machines usually have better A to D converters
than prosumer cameras, though I've heard the DVX100 has converters
as good as DAT machines. The main thing is if you encounter audio drop
outs on your camera, you'll have the DAT to "punt" to.

I would suggest you consider renting a multi track recorder like
a DA-88 or DA-38. You could then have seperate tracks for each
source. That gives you mix-ability after the shoot.

If you mix it all on site to stereo, you only have that one chance to get it right.
With a multi track you can overdub later and use only what works.
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Old February 5th, 2004, 10:49 AM   #8
 
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I agree with Jacques, but the caveat of sync still exists. Different clocks, unless locked to genlock, will create drift over long periods of time.
Using a DA 98, 88, or 38 is great, but then requires a mixer or multiple pre's, a person to carry it, an extra ear to listen to them grump about what all us sound guys grump about on any given day...:-)
Having a back up is ALWAYS advised in critical shooting situations. Very good point.
we generally record 2 channels of the same dialog, one channel -12dB from the other. This helps in the event of clipped audio, providing a second source.
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Old February 5th, 2004, 11:27 AM   #9
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<<<the caveat of sync still exists. Different clocks, unless locked to genlock, will create drift over long periods of time.>>>

True, audio sync over a long period can be a bit of an issue,
but I really haven't had that much
trouble. I can't remember whether the DA-38 has variable
speed playback, but the DA-88 does, so just a tweak here or there
takes care of what little drift there might be. Most stuff just seems
to drop in and work. Once in a while I had to lift out a frame to get things
back in order if I chose not to try and tweak playback speed.
(Canon XL1 can have this issue with its "not exactly 48K" recording.

As an audio guy, video's frame accuracy (or close enough to look great) is EASY.
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Old February 5th, 2004, 12:30 PM   #10
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Douglas:
You say:
In terms of audio, the camera and the dat machine are equal.

When I record in 16/48 on my PDX10p I hear a basrolloff a bit like the PD150 but less. When I record on my soundblaster in 16/48 I don't hear that. I think that my soundblaster will sound as a DAT machine. Am I wrong here?

That basrolloff is that typically Sony?
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Old February 5th, 2004, 12:37 PM   #11
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Stephanie, I'm way behind everyone around here when it comes to knowledge of audio (I've been buggng them mercilessly with questions of my own) but since you didn't mention how big a crew you're talking about having onboard, and you DID say it's no budget filmmaking (which is where I'm at), I'm going to add my two cents here. I've gone around and around with this issue, largely because I've come from a film background and I have friends with nominations and Academy Awards in sound, and they've made me paranoid about getting crappy audio. But that said, I don't have the budget to get the quality they're used to working with which is why I haunt these boards (like you are) to come up with as close as I can get, given my contraints. That said, I've decided to go with the Marantz compact flash recorder (mentioned earlier) to use as a simultaineous backup recording. It's DAT quality and I won't have the expense of transfering my DAT tapes to bring into my NLE. I'll just pop in the card.

Pros (IMO)-
*high quality backup at a minimal cost
*ease of use
*no moving parts that cause sync delays
*stays entirely within a digital environment
*sturdier than tape in hot environments where the sun can trash 'em
*small, lightweight, fits in a nice compact gear bag (lot of diff. options) that keeps it safe

Cons (IMO)-
*compact flash cards CAN fail
*to be extra safe and save $ on gig flash cards, will require layoff from your CF card to another medium (I'm planning on getting a stand alone CD burner for the field)
*have to sync up, which for me isn't that big a deal, but is does take additional time if you're under the gun

I plan on always having audio recorded to my DVX, one channel adjusted down as Douglas says, and generally that will be my primary audio track. The Marantz will be for shots which require more than two mics, and as a safety. Since I'm doing docs, I don't have the option to reshoot another day, or ADR if it's awful. If you're doing fiction, my approach may be over kill.

Hope this helps in some small way. Good luck!
Marcia
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Old February 5th, 2004, 12:50 PM   #12
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DA-88, as Jacques mentioned would be a great alternative. I'm curious if anyone has any experience recording timecode to one of your audio tracks and using that to simplify the syncing process. I know the timecode out of a camera is essentially an audio signal. What I'm not sure about is if there is anyway to transfer it back to timecode, without just mastering back to a video deck that has timecode in.

What I'm getting at is, is there a software approach to converting timecode from a wave file to a video overlay, or an "aux timecode track" in avid?
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Old February 5th, 2004, 12:54 PM   #13
 
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Jan,
I wasn't as clear as I should have been.
Spec-wise, cams and dats are equal. Different DACs will make this spec discussion take a hundred different turns. For instance, the PD150 has poor audio DAC's, so does the JVC 500. The XL1 is quite good, GL2 even better, IMO. The audio for cams isn't has harshly compared as DATS are. DATS often use the Cirrus converters, which cams almost never do as a result of cost. Not only that, but the pre's in a lot of the cams are tuned to roll off bottom and top end that's not in the dialog spectrum. It's like the manufacturer thinks the cam will be used only for dialog or something. Look at the curves of many cams, you'll see that they have odd upper and lower end rolloffs.
Your sound card *can* sound like a DAT, depending on the quality of the card.

Jacques, around here we have a joke about 'frame accurate is for sissies.' Everything we do is sample accurate.
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Old February 5th, 2004, 01:24 PM   #14
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<<<I'm curious if anyone has any experience recording timecode to one of your audio tracks and using that to simplify the syncing process. >>>

Yes, I have a DA-88 with the SY-88 sync card. The system worked
perfectly from the first time I had a gig with a TV truck.
They sent me timecode and I recorded it to the track the 88
has for this purpose. (We won't talk about ADAT syncing ;( )

Now days the DA-HR78 has the sync card built in and, AFAIK,
works great, costs less and can do 24bit/96Khz.



Used DA-88s are like $500-700(?) and you have the
tape as cheap storage.

<<<frame accurate is for sissies.'>>>

Haha! Ain't it true!
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Old February 5th, 2004, 01:28 PM   #15
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This is brilliant. Thank you.

We are fortunate enough to have separate hands (and ears) for boom, mixer, and camera ops, which seems to be a major concern when getting sound right.

In general, I'm hearing that the PD-150 does a solid job and the extra recording devices up the ante from a 'very good' to an 'excellent' quality. If I had the luxury of sitting in a dark theater, listening first to a clip recorded from the mixer straight into the camera and then a clip that had gone through DAT ~ What differences would I notice?

On devices other than DATs:
There was also discussion of dumping the sound straight onto a laptop with an enormous hard-drive to lessen the expense of having to re-rent the machine to do transfers... sane?

best,
Stephanie
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