FORUMS: list search recent posts

Horror Story from the Field - Sound problem with HPX170. Your opinion?

COW Forums : Panasonic Cameras

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
Jack Lam
Horror Story from the Field - Sound problem with HPX170. Your opinion?
on Jan 14, 2011 at 4:21:42 am

Hi all,

Here is a bad experience from the field that happened to me today. I'd like to share this with working peers like you and hear your take.

I was hired by a producer to shoot a sit down indoor one-person talking head today with a high profile figure. We shot with two HPX170. The wide shot has a shotgun mic. The close-up shot as a wired lav through XLR. (I don't have the exact model of the lav mic).

I was assigned to operate the closeup shot with the lav mic, while the producer monitored the wide shot. My shot has less room echo and sounded better. The producer and I set up the sound and the cameras together. We tested the sound before the session began. I was on the headphones during the test. Everything sounded fine.

We finished shooting the session without technical glitches. There was a couple fire truck sirens faint in the background. We paused our interview once to wait for it to clear. I had been listening for background noise and audio glitches throughout the session. If I have to be picky, I remember hearing a minimal level of hiss that sounded just like the normal noise floor of any prosumer camcorder (we know all audio equipment have a noise floor that is within spec, and it is more noticeable in headphones than from a TV speaker). At some point in the middle of the interview, I handed the producer the headphones. He listened for a few seconds and he said it sounded better than his shotgun mic.

But a few hours after we left, the producer called me up and told me that my shot has a lot of "static noise" from the lav mic. He said the noise happened in the later half of the interview (it was shot in a ~25-minute long take), and the static is so "overwhelming" that we had to reshoot it. He believes I have failed to identify the static noise that came in during the taping.

In the past, we have experienced hearing strong static noise with the HVX200 and the DVX in similar talking head settings multiple times. They were easy to identify during setup. In most cases we were able to isolate the problem to the 60Hz ground loop hum, interference of power cable being in close proximity to XLR cable, or if we had a dimmer in our lighting. This time we had no dimmer, and I didn't detect any 60Hz hum at all. I haven't seen the downloaded footage so I don't know whether it is analog noise or digital dropout / clipping.

I have shoot and monitored audio for literally hundreds of talking heads in the past and for different producers on professional jobs. They were done with DVX / HVX full-sized ENG cams / HDSLR with audio recorder, etc. I believe I am qualified enough to tell good audio from bad ones.


From my perspective, these are the few things I'm sure:
1) I didn't hear any audio problem during the shoot. Certainty nothing that can be called "overwhelming".
2) I playbacked the first 10 seconds of the 25-minute-long clip immediately after the interview. It sounded just fine.
3) The dialog and the noise floor sounded consistent throughout the shoot.
4) One of the two cameras was a rental (I can't recall which one).

Given the above, if my hearing is healthy and well, I can only conclude that:
1) The camera I was assigned to was faulty.
2) By design of the HPX170, the headphone circuit only shows me a live signal as opposed to a recorded signal. The signal chain to the P2 recording are processed differently than what I heard, and it is these processing that was at fault.

I'm not trying to find excuse or dodge responsibility. But in all honesty if it happens to me again, I can't think of any way to catch it on the spot. I know industrial practice usually warrants separate audio recorder for mission-critical shoots. Full-sized ENG cameras have robustly designed audio circuits to prevent this.

My fellow working pros, let me put this out to you all:
1) Have you experienced similar audio problem with this camera? (sounded OK in headphones, problem in the recording?)

2) There are times when we are assigned to work with prosumer equipment. How would you prevent nightmares like this? (We can't be expected to check playback for all 25 minutes on the field, right?)

3) To frame question #2 differently, in all humility, is there anything I should have done better to fulfill my job duty as a cameraman and ensure reliability in my output?

thanks a lot for your insight. I hope this discussion will help us get to the core of the problem and to help other shooters prevent this nasty situation.

Jack


Return to posts index

Michael Sacci
Re: Horror Story from the Field - Sound problem with HPX170. Your opinion?
on Jan 14, 2011 at 4:39:04 am

[Jack Lam] "2) By design of the HPX170, the headphone circuit only shows me a live signal as opposed to a recorded signal. The signal chain to the P2 recording are processed differently than what I heard, and it is these processing that was at fault."
You choose which one you want to listen to, if you monitor the recorded there will be a delay but that is normally what would be expected.

Without posting a segment of the issue there is no way of knowing.

BUT here is one thing, the HVX and HPX always record the camera mic. So if the producer is not turning off the camera mic he is listening to a mix of the built in Mic and the Lav, which would sound like crap. If you have a external mic you will not hear the camera mic through the headphones. Hopefully this is the problem.


Return to posts index

Jeremy Garchow
Re: Horror Story from the Field - Sound problem with HPX170. Your opinion?
on Jan 14, 2011 at 4:40:57 am

Do you have a copy of the footage?


Return to posts index


Jack Lam
Re: Horror Story from the Field - Sound problem with HPX170. Your opinion?
on Jan 14, 2011 at 5:02:35 am

I wish I do. But I don't have access to that footage. I haven't even seen it. I will check with producer.


Return to posts index

Jeremy Garchow
Re: Horror Story from the Field - Sound problem with HPX170. Your opinion?
on Jan 14, 2011 at 5:14:33 am

Yeah, before anyone plays the blame game, make sure you hear it for yourself.


Return to posts index

Michael Sacci
Re: Horror Story from the Field - Sound problem with HPX170. Your opinion?
on Jan 14, 2011 at 9:43:49 am

I got this call once, and it was in fact they were listening to channels 3 and 4. So if they send you a clip make for they send a source file. If they export they will be down-mixing all the channels to stereo.


Return to posts index


Frank Nolan
Re: Horror Story from the Field - Sound problem with HPX170. Your opinion?
on Jan 14, 2011 at 6:49:46 am

It is not totally clear from your post but are you saying you were monitoring the audio via headphones for the entire length of the interview or just the 1st part?



Return to posts index

Jack Lam
Re: Horror Story from the Field - Sound problem with HPX170. Your opinion?
on Jan 14, 2011 at 9:50:54 am

I was monitoring throughout the whole shoot. It sounded good to me and it sounded consistent from beginning to end. In the middle of the shoot I handed the producer the headphones only for a few seconds and then I continued monitoring.


Return to posts index

Steve Eisen
Re: Horror Story from the Field - Sound problem with HPX170. Your opinion?
on Jan 14, 2011 at 12:53:08 pm

It is very important to know what make and model your mic is. You also never mentioned the make and model of your headphones.

Personally, I have never experienced bad audio from my HPX-170 or HPX-500.

Steve Eisen
Eisen Video Productions
Vice President
Chicago Final Cut Pro Users Group


Return to posts index


Chris Tompkins
Re: Horror Story from the Field - Sound problem with HPX170. Your opinion?
on Jan 14, 2011 at 1:54:11 pm

There is a setting in the 170 menu to monitor audio as recorded or live thru.

That being said, I think the Producer is hearing Ch. 3&4

Chris Tompkins
Video Atlanta LLC


Return to posts index

Jack Lam
Re: Horror Story from the Field - Sound problem with HPX170. Your opinion?
on Jan 14, 2011 at 8:36:12 pm

That makes sense. But I doubt that coz the producer also owns the same camera and he has cut many many similar interview pieces.
I will double check with him.


Return to posts index

Jack Lam
Re: Horror Story from the Field - Sound problem with HPX170. Your opinion?
on Jan 14, 2011 at 8:40:50 pm

The headphones were Sony 7506.
I believe it was a Audio-technica wired lav. Something like the AT899. But I will check with them.


Return to posts index


Nate Stephens
Re: Horror Story from the Field - Sound problem with HPX170. Your opinion?
on Jan 15, 2011 at 9:39:39 pm

I have had a similar problem years ago with a Sennheiser Lav. Half way thru the shoot the battery started to go bad. You did not notice the static noise at first because it was intermittent. It took a couple of weeks to track down the problem. Now I make sure we always use fresh batteries or phantom power.

Sounds like a job for Sound Soap.

FCP, Mac Pro, Mac Book Pro, HPX500, HVX200, Betacam, Dvcam
Write for the Edit, Shoot for the Edit, Edit.....KISS Principle


Return to posts index

Alden Brigham
Re: Horror Story from the Field - Sound problem with HPX170. Your opinion?
on Aug 16, 2011 at 4:39:22 pm

Hi Jack,

If you're still monitoring this thread, did you ever figure out the problem? I had the exact same thing happen to me on Friday. Sounded great on set, no noticeable studio noise, bring it into FCP and there's a really strong hiss. I had a shotgun mic, and lav, so the internal mic wasn't being used, but it seems like hiss was introduced from the camera at some stage. Yikes!

(I was using an AG-HPX170)

thanks,
Alden



Return to posts index

Bill Farnsworth
Re: Horror Story from the Field - Sound problem with HPX170. Your opinion?
on Oct 8, 2011 at 11:51:33 pm

I am not Jack, but I did have this problem come up twice in the past.
The second was resolved by replacing the battery in the microphone. Hearing aid batteries can die in a matter of minutes.
The first was the worse of the two. The phantom power switch was not fully seated into the off position.
The audio was fine thru the headphones but on playback there was more static hiss and hum than the desired audio which was way in the background and off mic. This told me that the primary mic was not recording at all and the camera mic was bleeding over.
So. Replace the batteries early and often. Verify that the phantom power switches are fully seated in the off position when not in use. (I have taped them over just keep from accidently hitting them)
Regards,
Bill Farnsworth


Return to posts index


Alden Brigham
Re: Horror Story from the Field - Sound problem with HPX170. Your opinion?
on Oct 10, 2011 at 8:04:04 pm

Interesting, with more testing I found I had much cleaner audio using the mic on phantom power.



Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2018 CreativeCOW.net All Rights Reserved
[TOP]