Audio Mixers for DSLR Production--UPDATED 5/20/13
External audio mixers make it easy to adapt XLR mic and line-level sources to the audio inputs on DSLRs. The juicedLink Riggy Assist series of audio mixers are intended to adapt various microphones to be used with DSLRs. They can also provide additional features like phantom power and metering. The Riggy Assist does all this and more.
Using the juicedLink
The juicedLink series of mixers screw into the 1/4-20 thread under the camera. Some are small and light enough that you can also use a hot-shoe adapter and screw into the bottom of the juicedLink and mount the mixer over top of the camera. You can then mount cold shoe plates to the Juicedlink for your camera light, short shotgun mic, or wireless receiver.
Alternatively, the Juicedlink mixers can be rigged with a bracket to hold these accessories making the mixer the basis for further accessorizing the camera. The maker of the mixers calls this a Riggy Bracket.
You use a hex key to screw the Juicedlink's 1/4-20 threaded bolt into the bottom of your camera. Make sure to arrange the mixer so that your battery door can still open (if possible). With my small GH2 camera, this was not possible. I found myself in a pinch when I was on the site of a shoot and the battery in my camera ran out and I didn't have the hex key handy. Without it, you can't easily get the Juicedlink off and for me, there's no other way to get to the camera battery.
It's a trade off because setup also yields the thinnest profile, as there's no vertical height added for a big thumbscrew to mount the mixer. Just be sure to learn from me and put the hex key in your camera bag.
JuicedLink offers 9" audio cables to go from the mixers to your camera--whether the camera be 3.5mm or 2.5mm, as mine is. In the end, however, I opted to not use their cable because I wanted one that had "L" jacks on both ends. I didn't want damage to occur to either the mixer or my camera.
Adjustments
Also, I wanted to use a stereo mic that output to a 3.5mm stereo plug. There's no 3.5mm input jacks on the Riggy series of mixers. So I adapted it from 3.5mm stereo to two XLR jacks. Juicedlink once made a DT454 DSLR Audio Solution which offered an 3.5mm stereo input, in addition to two XLR jacks, which might have been more suited to this setup of mine, but that discontinued mixer is bigger, and has less of the advanced features that have been incorporated into the Riggy series.
I ended up rotating the mixer from the normal pictured setup. I put the audio pots on the left side, instead of facing the rear of the camera. This put the controls on the left side where I am used to finding the operating controls on my camcorder. It also places the XLR jacks out the front, meaning the clutter of cables didn't stick out further to the side. It was tucked under the lens, as you can see in the video.
This placed the battery door right against my finger that rested under the camera grip, holding my camera system up. The molded lines on the battery door ended up rubbing my finger to irritation over the course of a 9-day shoot, but it's not likely to bother anyone if you're shoot's not this long.
Powering the juicedLink
The juicedLink Riggy Assist mixers need a 9v battery, and how long it lasts depends on what features you turn on or leave off. You can turn the phantom power on or off, you can even turn unused preamps off, you can turn the meter on or off, etc.
On average, you can expect to get between 8 and 14 hours, depending on which features you enable and how hot you run the headphones.
Related Articles
This article and accompanying (hear it for yourself) video will compare the results of capturing audio with a $20 Audio-Technica wired lavaliere mic and a $200 professional mic from Sony directly into a DSLR. Is the $200 Sony really worth the 10x cost?