FORUMS: list search recent posts

Wireless microphone static drops sync

COW Forums : Audio Professionals

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
Vickie Sceifers
Wireless microphone static drops sync
on Feb 18, 2013 at 11:39:19 pm

I typically record a presenter talking to a small group-like at a hotel banquet room. I have a wireless mic that goes into a Zoom H4 (my camera is a D7000, so I record to the external device). For the last several sessions, when I get back to the office and review the files, I'm finding the audio not only has occasional static, the sound completely drops out (but keeps sync), or sometimes there's a "staticky" blip sound that drops the audio out completely for a few frames, thus making sync to video a pain. I monitor it during the live recording, and do notice it, but there's little I can do during the actual program to try to remedy it.

As an aside, the waveforms are very flat, almost looks like a flat line with dust on it. :-)

I've figured out it's not the Zoom because the same thing happens when recording audio to my Zi8. I've tried researching this online, but it's very hard to find my exact issue among the mass of similars. I've seen reference to squelch, but not sure really where to go with that.

Any help would be greatly appreciated. I am frustrated beyond belief at this point!

I've attached an example of what's wrong; the first clip blips a lot. The second one really shows the going out of sync.

audio static sample




Thanks.
Vickie


Return to posts index

Vickie Sceifers
Re: Wireless microphone static drops sync
on Feb 18, 2013 at 11:39:39 pm

Second video:

Example of losing audio sync



Return to posts index

Ty Ford
Re: Wireless microphone static drops sync
on Feb 19, 2013 at 5:10:28 am

Hello Vickie and welcome to the Cow Audio Forum.

The fact that you're getting interference on your wireless is an indication that there is traffic on "your" frequency. If that's the public safety band, you are interfering with federally licensed communications and you are breaking the law. You are on their frequency.

Although moving the receiver closer to the transmitter may help, my advice to you would be to stop using these radios at once.

Regards,

Ty Ford
Cow Audio Forum Leader

Want better production audio?: Ty Ford's Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford's Blog


Return to posts index


Peter Groom
Re: Wireless microphone static drops sync
on Feb 20, 2013 at 12:22:06 pm

Hi Vicky
Aside from any legal reasons about the use of your radio mics in your part of the world that Ty mentioned.

If the radio signal is dropping out as a result of some interference, then as youre going into a zoom h4n, which MUST be analogue input, then this CANT be the cause of your sync drift.
so lets split this in 3.

1) Is your audio arriving at the zoom ok. Your headphones will tell you if this is stable (no holes / clicks etc) If it has holes in it on the cans whilst recording, its a frequency / intereference issue (or a cable fracture) . Try adjusting the frequency to a new one, or adjust the squelch. Moving receiver closer to transmitter, unblocking line of sight and making sure there are no mobiles in room or that they are turned off.
Also check that you dont have phantom power enabled on the recorder for a device that doesnt need 48v up it jacksy.

If the cans have no issues / holes in audio, then it ia s recording error. Try a different recorder.

2) On the sync side. Have you correctly matched sample rates etc on the zoom recorder and whatever you are importing the audio into for picture editing. As the files from the zoom will be inported as a digital import, the sample frequency , bit depth MUST match. What NLE (editor) are you using.? Go for 48k 16 bit if in doubt.
If they are mismatched they will drift over time. Teh camera MUST also agree with these settings.

3) recording looks like a line with dust on it????
1) are you going into your zoom mic or line level. Which audio connections are you using on the zoom. What connectors are u using from the radio mic, or is it coming from an amp or desk?
What do the meters on the zoom say you are peaking at?
What do your ears say. ? Are you monitoring the zoom constantly?

The zoom has a full scae meter topping at 0. Your input audio from the mic should be sitting regularly around -12 ish.

let us know how you come on, unless youve already been carted off to guantanamo bay for radio mic mis use!

Lol.
Peter

Post Production Dubbing Mixer


Return to posts index

Vickie Sceifers
Re: Wireless microphone static drops sync
on Feb 25, 2013 at 6:51:52 pm

Thank you, Peter. I will be doing some more testing this week and will update the thread.

"Lines with dust on it" means, I probably had the wrong setting - line in instead of mic in. I think this will be an easy fix. I haven't used this device very much, so I seem to have to relearn the settings every time I get it out. I def need to doublecheck the bit depth, though, and match things with my Nikon D7000 and FCP7.

Vickie


Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2017 CreativeCOW.net All Rights Reserved
[TOP]