Humming noise in video taping

[Gbaum]

I have been working with a friend who is a Minister of a very small country church that tapes a 1/2 hour television church program for shut-ins. They recently started using a Panasonic PV-GS15 digital video cam corder and the sound was horrible using the camera mic. They then tried plugging their mic mixer into the ext mic plug on the camera and the sound was much bettter but then had this annoying humming noise in the audio. The cable they are using is shielded. Anyone have any ideas as to what this hum may be and how to get rid of it? We are all amateurs when it comes to audio problems and any help and advice would be greatly appreciated. Thanks!

[xstatic]

Try plugging the camera into the same AC circuit as the Console. If that is not an option, you can try using a ground lift apadtor on the camera power in a pinch. If you are using batteries in the camera instead of AC power, run the signals through a DI box and use the ground lift switch on the DI.

[cmchamp]

There probably isn't a ground (3rd) plug on the camera's wall wart. In this instance, should using battery power on the camera result in the same hummmmm, run things through a DI for two reasons: 1) proper impedance matching 2) ground lift switch option. You'll have to get or make an XLR to MINI 1/8" jack cable.
C.

[AudioBond]

Also try using an iso transformer. It is a must-have for interfacing audio and video gear! Rapco makes some small ones that work well. They are called Isoblox. Not sure if sweetwater carries them, but certainly ask. I don't think that they are that expensive. Check em out on Rapco's website. They are straight up XLR in and out. Work like a charm most of the time.

Hope this helps!

later,

-Chris

[michaelhoddy]

Originally posted by AudioBond
Also try using an iso transformer. It is a must-have for interfacing audio and video gear! Rapco makes some small ones that work well. They are called Isoblox. Not sure if sweetwater carries them, but certainly ask. I don't think that they are that expensive. Check em out on Rapco's website. They are straight up XLR in and out. Work like a charm most of the time.

Hope this helps!

later,

-Chris

This is exatcly what I was thinking.

[sgsound]

I had the same problem when using a lapel mic on my sony. I didn't have a mixer and a DI so I turned the light on and it worked. Not sure why but it got rid of my hum.

[MidiMagic]

You may have one of the following:

1. A ground loop. Try an Ebtech Hum Eliminator in the audio lines to the camera.

Note: NEVER break a ground loop by interrupting the power line safety ground.

2. Sync buzz getting into the audio lines. The Ebtech unit above might also fix this. If it does not, put a preamp set at unity gain between the audio mixer output and the camera.

3. Power line incompatibilities: Try putting the mixer and the camera on the same power strip. Also try it with the camera on a known different circuit (you will probably need the Ebtech unit for this).

4. Garbage getting into the power lines from the camera. Try a power line low-pass filter on the camera power cord.

5. RF from the camera getting into the mixer. Move them farther apart. Try putting the snap-on ferrites Radio Shack sells on any audio line running close to the camera.

6. Acoustic noise from the camera picked up by mics. Move the camera or put a sound shield around it.

7. Hum fields from the camera's power wart being picked up by a direct box. Move the direct box away from the wart.