Audio Specs for the Panasonic DVX100

[Sara Glaser]

Hey all,

I'm new to this site so I'll introduce myself. I'm 28, female, and I'm an audio engineer:) I started in music studios doing the usual, left the studios and freelanced a bit, somehow ended up doing audio restoration on film for re-release on DVD usually in PAL for a couple of years, dabbled in live sound and mastering as well. At the moment it appears I've landed on set and have recently started working as a production sound mixer (while occasionally also being the post sound mixer and sound designer depending on how low the budget is and how much they want to utilize me:)

So now that I've introduced myself a little, here's my question. What are the audio specs for the DVX100 and why can't I seem to find them on the Panasonic website? I've already checked out Adam Wilt's site (which has a tiny blurb on the audio/video sync issue...why would you build it that way?????). I've also gone to John Beale's site and read what he had to say about the levels and how they work with the ALC.

The setup I'm looking at is the director has talked to the producer who told him that the DVX100 records audio the same as a DAT:) The director then called me to get answers. Aside from the built in limiter (how good/bad is it?), I need to know what my frequency response curve is. What kind of dynamic range does the camera allow the audio? Is there a built in noise gate? What does it do, where does it stop, and is it defeatable? If I throw a PD-4 into the chain between my mixer and the DVX100 (guess what I'm trying to keep) do I need to set levels at -20dB on the camera or can I push it hotter say -3dB (it's not a very *loud* film) Also, the sync issue. I'm sending audio to the camera so we can have dailies with sound. The DAT is my recommendation for good sound as well as a back-up for the inability (without kicking the cameraman out of the way) to monitor levels. Obviously it's 24p, should I stick to 29.97 NDF at 48k? I only have the option of 44.1k or 48k otherwise I'd record 30 NDF at 48.048k and just have them play it back at 48k for sync. If I only have the option of bringing my audio through the mixer and straight to the DVX-100 can anyone recommend a good in-line limiter for film sound that I can find at a rental house?

I think that's all for now:) Thanks everybody:)

-Sara Glaser

[Patrick Bower]

Look for the review by Jay Rose on www.dv.com
Patrick

[Christopher Go]

As Patrick suggested, here's a brief review of the Panasonic AG-DVX100's audio capabilities, written by Jay Rose from DV.com. You do have to sign-up on their site however before you can view them:

http://www.dv.com/reviews/reviews_it...eview/wilt0203

http://www.dv.com/print_me.jhtml?Loo...eview/wilt0203 (This link is the printer friendly version)

It is a side column article called "An Audible Sigh of Relief," which accompanies Adam Wilt's review of the camera.

Won't answer all of your questions I think, but it should give you a better idea of what this camera is capable of.

[Sara Glaser]

Thanks guys.

I checked out the Jay Rose link and got the frequency response info from his article. EXACTLY what I was looking for in response to the first bit of question. I'm still curious about how much "camera sound" I can expect to have bleeding onto my audio. Also, what about the limiter? Of course, if we're going to rent a limiter why don't we just keep the DAT machine instead?!?!?!? Hey man, I just work here:) Okay, that aside, so the Panasonic 24P TC isn't true film 24P but interlevered if I'm understanding this correctly. Also, the DVX100 has what amounts to a 2-frame offset where audio leads video. So.....since the whole point of me sending the sound to the camera is so the director can have instant dailies, what's a suggestion for tricking the camera into sync with audio?

-Sara

[Barry Green]

<<<-- Originally posted by Sara Glaser : what's a suggestion for tricking the camera into sync with audio?

-Sara -->>>

For "instant dailies" it will look basically in-sync right off the bat. If you're using a DVX100A (the new advanced model) it apparently employs a delay circuit so that the audio and video written to tape are in sync. The audio delay only happens on the original DVX100. And it's only two frames, most people don't even notice it. The camera was out six months before anyone discovered the delay.

If it's noticeable, we fix it in post by sliding the audio over. How you can do that in real time when recording, however, I don't know... you'd need some sort of 1/30th-of-a-second audio buffer...

[David Ziegelheim]

<<<-- Originally posted by Sara Glaser :
Okay, that aside, so the Panasonic 24P TC isn't true film 24P but interlevered if I'm understanding this correctly.-Sara -->>>

No, it is 24p. It stores the the even half on one interleave, and the odd on the next. But it is a single frame. Alternate 1/2 frames are duplicated, the duplication pattern varying if it is 24p or 24pa.

When loaded in to the NLE, the duplicates are stripped an you are left with a true 24p image.

[Christopher Go]

Best bet would probably be to slate the beginning of every take, and maybe even at the end of a take with an upside down clapboard. That way you can adjust for synch in postproduction, and move the audio as Barry suggested. Synch the sound of the clap with the visual and you should be fine - or so I've read!

I have yet to do double-system sound myself!

Speaking of double-system sound, instead of DAT I am leaning toward the Fostex FR-2 Field Recorder (click to visit Fostex's website) for my audio.

[Ken Tanaka]

Sara,
If you're not locked into the 100 you might want to look into the 100A. It is my understanding that the DVX100A introduced some improvements to 24P audio synch over its predecessor. I have both the 100 and the 100A but cannot verify this for you.

You can find more comparative information at Adam Wilt's site if you've not already visited his site.

[Sara Glaser]

<<<-- Originally posted by Ken Tanaka : Sara,
If you're not locked into the 100 you might want to look into the 100A. It is my understanding that the DVX100A introduced some improvements to 24P audio synch over its predecessor.

Ken,

Thanks for the heads up. I actually don't know which one we will be using on the shoot. *blush* DETAILS MAN DETAILS!!! ...but I have a pretty good feeling I'll be making it my business to find out ahead of time.

-Sara

[Sara Glaser]

<<<-- Originally posted by Christopher Go : Best bet would probably be to slate the beginning of every take, and maybe even at the end of a take with an upside down clapboard. That way you can adjust for synch in postproduction, and move the audio as Barry suggested. Synch the sound of the clap with the visual and you should be fine - or so I've read!

I have yet to do double-system sound myself!

Speaking of double-system sound, instead of DAT I am leaning toward the Fostex FR-2 Field Recorder (click to visit Fostex's website) for my audio. -->>>

Actually Chris once you get to editing that only helps a little. Obviously the head sync or the tail sync on a take SHOULD be mandatory. However, you can still sync without it. All you really need is an impact noise that is established on camera (production sound - post sound cannot EVER be used to sync reliably). A good example is a footstep, a door being shut, a close-up of a dinner plate being set on a table, lighters, etc. Once you have the sound you can sync the waveform to the TC on the video. Most of the general public can't see anything unless it's around 2 frames out of sync. This would explain why the DVX100 was out for 6 months before somebody said something. When I did audio restoration we synced everything. Our cutoff was 20 subframes. Anything less than that we didn't have to sync. Of course if it bugged the shit out us we did it anyway:) But I digress. The point is, if you have a head clap and a tail clap and they sync you might not actually have stayed in sync. This is because if you have a variable drift it is possible for it to come back in sync with itself by the end. In other words you have to watch the whole thing from beginning to end in order to make sure. When I did restoration we worked on DVD re-releases in PAL. Sometimes you'll get a segment with a head pop and tail pop but it's actually been cobbled together from a multitude of reels and given to you as one. Guess how you find this out?:) Theory is a wonderful thing but it allows to much for human errors and miscommunication. In the end you can only trust your ears.

I'm taking a look at the Fostex though:) Man, my director needs to give me a bigger budget to play with:(

Girls and their toys:)

-Sara

[Sara Glaser]

<<<-- Originally posted by Christopher Go : *snip*

Speaking of double-system sound, instead of DAT I am leaning toward the Fostex FR-2 Field Recorder (click to visit Fostex's website) for my audio. -->>>

Chris,

I think I like the look of the PD-6 better. I like to have as much control of the audio going down as I possibly can. That way I can get the cleanest, richest, best sounding audio that circumstances allow for. Check out the link at
http://www.fostexdvd.net/fxdvd_route/docs/product/dv40/overview.htm

-Sara

[Christopher Go]

In the end you can only trust your ears

I believe you! Once we get started on double-system I'll have to report back on our results. Your post reminds me that there is so much work and research to do... If the budget allows, I may just hire someone to do the audio.

That PD-6 goes for $8,500 at B&H Photo! Click on this for more info. I imagine you would have to rent if you're shooting with AG-DVX100(A)s.

I'm eyeing the Fostex FR-2 only because I'd like to purchase the unit since there's not too many places to rent from here and for reasonable prices.

I'm also looking forward to Sound Devices' 722 and 744T field recorders when they come out in April/May. Click on this link for preliminary features. The 722 will go for around $2000 US and the 744T for $4000 or so.