LostGround? - Radio Interference

[jbbpvdri]

Dear DVX Users,
I recently experienced an audio problem using the HVX. Audio being recorded to P2/HD-100 and output from the headphone monitor was mixed with a radio station. We used our standard audio rig for this interview situation (a lav and shotgun mic going through mixer which was hardwired to the camera). All audio was clean at the mixer but not after going to the camera. Our work around was to only use the lav (linked to camera using lectro 201/211s) connected directly to the camera. All other scenarios caused the radio station to bleed into the recording. The shoot was in NYC. Any ideas?

[Jim Carswell]

Sounds like the shielding on your snake running betwen the camera and mixer is bad. Specifically your return wires.
Jim

[stuckfootage]

In an interconnected setup like this, it's important to make sure everyone has the same Edison power. Try to connect all equipment to a single AC source and distribute from there.

Secondly, use balanced shielded cables (make sure the mixer output is balanced XLR, and switch the XLR connectors on your HVX to LINE for your mixer feed).

Thirdly, avoid routing power and audio in a loop. Instead of having your power run on one side of a room, and your audio along another wall, you can run audio and power next to each other, that is, IF the signals are balanced.

Finally, you may need to break one ground connection. That is, the camera or mixer may be connected to ground by both the audio cable(s) and the power cable. The unsafe way of disconnecting one ground to lift the ground pin from a power cable. Don't do that! The safe way is to use something like a direct box with a ground lift. This can be connected to the XLR inputs of the HVX200 and powered by the camera's phantom power.

The above tips are quite useful for radio interference, hum, and buzz.