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November 9, 2010 at 11:30 PM #46018
I am recording our Sunday church service with a Canon Vixia hf s200. I have a single audio cable running from our sound boards tape out, directly into the camera. the audio is fine, no distortion or hum or anything. When i connect the a/v cable to a tv, with a male to male a/v cable (connected to TV) connected to a coupler to male a/v to male 1/8″ (connected to camcorder) i have a hum in the recording, which doesn’t make sense to me, considering it is sending the signal to TV, not from TV to camcorder. the hum is only there when i connect the cable from the camcorder a/v out to the coupler which connects to the a/v cable into the TV…any reason why?
November 9, 2010 at 11:55 PM #190158
so i tried to recreate the setup at home, and there is no humm. The hum only comes around when the camcorder is connected to the tv at church. Could the tv be the problem? unfortunately i only have access to the church set up on Sunday mornings.
November 10, 2010 at 11:31 AM #190159roadtriprayParticipant
When you recreated the setup at home did you use the same cables you used at church? Cabling is a very common point of interference. The first step is to eliminate the cables themselves. If you can use the same cables at home and get no hum, i would check the path of the cables at church to see if the cable is in proximity to sources of “noise.”
November 10, 2010 at 6:46 PM #190160
yes, i used the same cords. the only time there is a hum is when the cable is connected to the tv.
could the tv be sending a signal back through the cables? like maybe its a cheap tv?
November 10, 2010 at 7:19 PM #190161
what you need is a DI-Box to isolate the grounds (eliminate ground loops) and to match the impedance. search DI-Box on Google and you will find one that meets your needs
November 10, 2010 at 9:13 PM #190162
a di box to send the camcorder feed to a tv?
November 11, 2010 at 2:06 AM #190163CvilleParticipant
I believe the DI or direct box is just for audio. We use them all the time at our church to connect our computer audio out to the sound board as well as various instruments we have had noise issues with.
November 11, 2010 at 5:20 AM #190164XTR-91Participant
It could very well be the TV that’s causing interference. The RCA audio cables (red and white) are not balanced audio like three-pin XLR. If it’s TV output you’re trying to feed, why not just tap into the TV’s audio feed and use the camera’s a/vjack for sending it to the TV.
November 11, 2010 at 5:23 AM #190165XTR-91Participant
“When i connect the a/v cable to a tv, with a male to male a/v cable (connected to TV) connected to a coupler to male a/v to male 1/8″ (connected to camcorder) i have a hum in the recording”
Are you sure your camcorder’s “A/V” is not set to input?
November 11, 2010 at 12:46 PM #190166
you have a ground loop! the ground from the TV and your camera are causing this… you need to isolate them here’s a post I found sometime ago on DVinfo.net
“I ran into a similar problem while recording a kick-boxing match several
years ago. The camera audio was fed from a Mackie 1402 and video out
was feeding a projector hung from the convention center ceiling.
A severe hum was introduced when the video was connected. The problem
was fixed by inserting an isolation transformer on the video out. Video
isolation transformers are available at Markertek.
Of course I didn’t have one in my bag, but the second camera on the
shoot was operated by a local TV station tech. He was able to find one
at the station and returned with it just before the show was to start”
i had the same issue the other day and this resolved it… mi mystake i call them all DI-Boxes ( this one is labeled VIDEO…
hope this helps you…
November 18, 2010 at 5:38 PM #190167
Thanks FX1shooter! I will try that out this week. Question: why does it work fine at my set up at home (the ONLY thing different is that I have a way smaller sound board). could it be that i need a DI box or isolator going from the board to the camera? or just the camera to the tv…
November 19, 2010 at 12:23 PM #190168
it’s simply due to different potential (voltage) on the ground of your different devices and is a commun and well known problem.
to be safe i would make sure i had one for both!
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