I’ve done sound for shoots with Red cameras on a number of occasions, and in summary they aren’t great for sound, and have some variables in there depending on the version of the firmware that is being used. I suggest always recording double-system sound with Red cameras as it currently stands.
Here are some notes on the set-up I used with a Red Scarlet recently along with my Sound Devices 442, and Sennheiser G3 wireless transmitters and receivers for reference in case it is useful:
442 out at Mic Level to Sennheiser SK100 transmitter using a Sennheiser Line Output cable.
Set input Sensitivity of SK100 to -15dB.
Transmits to Sennheiser EK100. Set AF Out on it to 0dB.
Preamp gain on Red set to +15dB.
This gets the tone from my 442 into the Red reading on the meters of the Red at -20dBFS.
That was for 1 channel input with the Red’s analog inputs set to Unbalanced.
I also run a cheap lapel mic into the second mic input just so that there is always some guide audio in case my wireless hop goes down. In the case of the crappy mic I use, I need the preamp gain on the Red set to +57dB for that input.
Also, please note the fan settings in the menu on the Red, and make sure that it is set to turn down to minimum speed when shooting.
Addendum – 8 July 2014
– The standard Sennheiser 3.5mm TRS to 3.5mm TRS cable that comes with their G3 kits doesn’t work with the Red. The Sennheiser cables are wired different to what is required. A standard wired 3.5mm TRS to 3.5mm TRS cable works fine however from the Sennheiser G3 wireless receiver to the Mic Input.
– I recommend you get a 3.5mm TRS to female XLR cable for your kit. This would make it much easier for you and others to connect either mixers or microphones to your camera…
Red make one:
http://www.red.com/store/products/xlr-microphone-cable-20/790-0229
But you can get a no brand option for cheaper.