audio problem with HMC40 xlr rig

droliff

droliff

Active member
Hi all,

Dennis here. I am a newbie filmmaker. I've had a Panasonic HMC40 with XLR adapter and Rode NTG microphone for about 8 months now and have done various projects with it. Everything has been working fine up until last weekend when I shot an event at a church, downloaded the footage onto my Mac Pro, opened the footage in Final Cut Express and discovered a major problem with the audio tracks. I shot the footage on heavy sticks with a Manfrotto fluid head as I've done in the past. I am getting a heavy rumbling in the audio and it sounds like it's breaking up. Parts of the audio are missing completely. Please go to this link for a detailed visual of my setup and an audio sample of the problem.
Does this sound like a loose connection? I'm stumped and want to get the issue solved before shooting again.

Thanks in advance for any input.

Best,

Dennis

Dennis Roliff Photography
 
helpful, thanks

helpful, thanks

Hi Jordan,

Thanks for the note. This thought never occurred to me (again, I'm new at this and always seem to learn things the hard way, lol). The Rode NTG-2 microphone that I have is capable of being powered either by an internal AA battery or by 'phantom power' via the camera. I had a friend who is a video pro tell me that the +48V switch on the xlr adapter is for switching to phantom powering the mic. As you can see in my visuals, this switch, on input 2 (the input that I am using), is in the 'off' position. So the mic was being powered by the internal AA battery, which I installed when I purchased the mic about 6 months ago and have never removed. I see on the literature that came with the mic that it is recommended to remove the AA battery when the mic is not in use because it continually draws power. I am wondering if a weak AA battery is the culprit then? Is it best to run the mic on phantom power? My cameras battery is a Panasonic VW-VBG6 and has a 6 hour life when fully charged.
Also, when running a single microphone, is it best to use input 2 and put the channel selector to channel 2 rather than 1•2?

xlr_001.jpg
xlr_001.jpg
xlr_001.jpg
xlr_001.jpg
xlr_001.jpg



Thanks in advance for any input.

Best,

Dennis

Dennis Roliff Photography
 
I'd guess the culprit is probably a low battery, but toss a new battery into the mic to test, just to be certain. Going to phantom will have a slight impact on the battery life of the camera, but it shouldn't be too bad.

I'm not familiar with that camera at all, but if it's possible to record the mic to both channels and set one to a lower level to give you some insurance against unexpected peaks, that would be the way to go. I'm assuming that's what the CH Select on the second channel does, allow you to take the input of ch1 and route it to ch2 for that safety track - check your manuals to be sure.
 
The ag-mya30g adapter manual says that when you select CH1.2 you get the signal from input 2 recorded on both CH1 and CH2. When you select CH2, you get the input 1 connector recorded on CH1 and the input 2 connector recorded on CH2.

Actually slightly counter-intuitive isnt it? I'm pretty sure a bunch work this way though.
 
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