Multi-Channel Audio for DSLR Video

I was recently sent the following question:

In your video you talk about possibly having a Shotgun mic and 3 wireless mics hooked into the Azden FMX-42 field mixer at the same time, and the Azden mixer hooked into your Canon 5D.  Is the 5D capable of recording 4 channels of sound?  Will it import into Final Cut Pro with all 4 channels? If so, what cables do we need?

Great questions. Unfortunately, the 5D – like most video cameras – only records two channels of audio.

Indeed, the Azden – and the vast majority of other field mixers – mix all their inputs down to two channels of output: “left” and “right” channels. This is because, until very recently, ALL cameras only recorded two channels of audio. One of the functions of a field mixer has historically been to “mix” – i.e. blend – multiple inputs (the standard used to be three, but now it’s four) down to two outputs, so that a camcorder could capture sound from more than two sources.

Traditionally, the breakdown has been some variation of the following, depending on the setup and the type of program:

– Boom on one channel, lav mics on the other

– Camera mic on one channel, off-camera mics on the other (not an option with the 5D)

– Most important speaker (e.g. host) on one channel, all other audio (e.g. guests) on the other

Now, with all that said, there are some cameras that record four channels of audio – my Sony S270U, for example. However, I have never been able to get Final Cut to recognize or import channels 3 and 4, so I’ve found the capacity to be of limited utility! (In fairness, I have seen Final Cut digest 4-channel Panasonic data just fine.)

For my bigger 5D shoots, I hire a friend of mine who runs audio for a number of nationally-televised reality shows. He uses a $6,000 Sound Devices mixer/recorder that has 8 analog inputs, and records a total of 12 tracks to independent WAV files on an internal harddrive. With that kind of hardware, there’s no issue: I take a stereo feed from the mixer to the camera as a safety/reference track, and use Pluraleyes to sync it to the WAV files in Final Cut.

There are some other – less pricey – alternatives to the top-of-the-line Sound Devices, but there’s still a pretty big gap between the regular two-channel-output field mixers that cost a few hundred dollars, and the ones that do internal recording.

If you can get away with mixing your four inputs down to two outputs, you’re good to go. If you can’t, you might want to look into hiring a local audio operator with a Sound Devices HD recorder (or something similar). I wouldn’t recommend trying to rent a high-end mixer to use yourself, as the learning curve on the operation of a machine like that is pretty steep. Indeed, for any shoot when you have the budget for it, you should hire a professional audio op.



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2 thoughts on “Multi-Channel Audio for DSLR Video

    • Wow! I was certainly NOT aware of that. Thanks for the heads-up. I’ve been waiting for a product like that, and I bet a lot of other people have been too. It’s available from B&H (along with a free carrying case) here: http://bit.ly/c2YJh4

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