Get low-noise audio with a DSLR and a wireless microphone

The more I do video production with my Nikon D4 DSLR, the more I have come to like how it handles in-camera audio with an external mic attached. One of the big issues with the first generation video-enabled cameras like the Canon 5D Mark II and the Nikon D3s was they had limited audio capabilities. Many producers felt the need to record separate audio into a recorder like a Zoom H4n and then sync it later in post. What a pain. It’s one of the reasons I put off switching from a traditional video camera to a DSLR.

Sennheiser G2 Wireless MicWith my Nikon D3s, I went the route of trying to use a JuicedLink audio interface to manage my audio. The unit bolted on to the base of my camera, which made it feel bulky. It had great features like dual XLR audio inputs, levels monitoring and a headphone jack, but the truth is, on that piece of equipment, I could never dial in a clean audio signal.

A big part of the problem was the way the D3s handled audio with only three levels settings—high, medium and low. The last time I used the camera with the JuicedLink, I had such a high noise floor (a low background hiss) in my interview audio that I just left it on the shelf after that. Soon after, I upgraded to the Nikon D4 and have found I could generate low-noise audio, especially with a wireless mic, all without all the add-on accessories.

I like using a DSLR to shoot formal interviews. The shallow depth-of-field makes the subject look great. I use my trusted Sennheiser G2 wireless mic for my audio. Be advised,  out of the box the gain on these mics are set really high. The first time used it,  I had such distorted audio that it ruined the video story I produced for the newspaper. I quickly learned how to turn down the levels and make them work with my Sony Z1u video camera.

When I first used a wireless mic with My Nikon D4 (plugged directly into the camera’s mic jack,) I found the same high noise floor that my JuicedLink produced. After fooling around with the settings I came to this conclusion: I had to turn the levels on the mic back up and turn the camera audio levels way down. With the right balance (the mic sending the clean signal, which I assume overpowers the camera’s weak pre-amps), I now  get quality audio without a lot noise-floor hiss.

Is my camera audio as good as recording separately to a Zoom H4n? I’d say depends on what you are doing with the video. If its going to be broadcast on TV, or destined for the big screen, then maybe not. But, if you are producing for the Web like I am, I’d say it’s more than good enough.

You can hear an example of what my wireless Nikon D4 audio sounds like in the interview and voiceover audio in this video I produced for a speech therapy clinic:

Here are my settings:

On my Nikon D4 (the same as on the Nikon D800,) I set the camera on manual and dialed the camera audio down to number 4 level.

On the Sennheiser receiver pack (the one that connects to the camera) hit the “Set” button then toggle the left selection button until you get to “AF Out.” Hit “Set” again and toggle the left arrow until you see -12 Db. Hit “Set” again.

Next on the transmitter pack (the one connected to the lav mic) hit “Set” then toggle to “Sensit” and hit “Set” again. Toggle until you get -06 Db. Hit “Set” again.

Now do a test. Watch your in-camera levels. If they are too low, bump up your audio level to “5,” but no more. If they are still too low go back into the mic pack and set the AF Out level to -6 Db.

Just remember that there is no phantom power with DSLRs. You need battery power from the mic for it to work properly. I sometimes put my big Sennheiser ME-60 shotgun mic on top of camera and it works like a charm with very low noise. Just make sure you have a fresh battery in mic and that it is turned on. If you don’t, you won’t record any audio.

One of the great things about the new generation DSLR’s is that they have headphone jacks to monitor your audio. Use it, or you’ll regret it later (trust me on this one.)

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Great audio starts in the field

You’ve probably heard it a thousand times before–viewers will forgive you for bad video, but they’ll bolt if forced to listen to bad audio. Wind noise and distorted audio hurts the ears.  Have a video where the subject can’t be heard over distracting ambient nosie? I, like most people, just hit the back button on my browser. Here are some audio tips I’ve learned from my time behind a video camera:

  • I’ve watched too many videos and audio slideshows where wind noise has ruined an interview or mucked up the ambient sound. It is important to use a quality microphone with a windscreen to minimize this horrible sound. A couple of years ago, I climbed windy Mount St. Helens with my video camera. I bought one of those fuzzy windscreens that looks like a tribble (yes that is a Star Trek reference.) It worked brilliantly. For reporters stuck with a point and shoot cameras, good luck. Your audio is at risk every time the wind blows.
  • If you use a lapel or wireless mic on a subject, the rule of thumb is to place it at the second button on a dress shirt. Don’t place the mic inside the shirt or against skin, as that will add a rustling noise every time the subject moves. Listen closely with headphones for noisy clothing like ski jackets or jingly jewelry. You will beat your head against your keyboard trying to edit around these distractions.
  • Nothing screams amateur like a dangling mic cord on the outside of a subject’s clothing. Take the time and run it up inside the subject’s shirt or top. If it is a tee shirt, run the mic out the collar, and down a couple of inches. Pinch the shirt and clip the mic so that it is facing up. It doesn’t always look the best, but will give you better audio quality than if you just clipped it to the collar. Also, take charge of placing the mic. The subject usually has no clue of how to clip it correctly. Stringing it under their shirt, well, I’ll leave that to my subject.
  • If you are using a wireless mic, make sure to turn off all cell phones near the transmitter and receiver. Our company’s smartphones interfere with our Sennheiser G-3 wireless kits. This random interference will happen only when the subject says something profound.
  • When I shoot interviews with a wireless mic,  I record in two channels of audio ( I use a Sony XDCAM EX-1 with two XLR inputs.) One channel is the wireless mic and one channel is my on-camera shotgun microphone. That way if I get interference or distortion, I can use the other channel in a pinch. This has saved me countless times. This also works well for stories where you have one subject that you need to wire up. I have that channel always recording, even if I’m just shooting b-roll of something else. I can always drop that channel when I’m editing. Great things are said when the camera is not in the subjects face. Just remember to turn off the receiver if your subject heads to the restroom…
  • Get a curly cord extension for your on-camera shotgun mic. That way when you do a quick on tripod interview with someone, you won’t have to stick the camera so close to his or her face. A TV news shooter once told me that sound falls, so place that shotgun mic about a foot out and below the subject’s mouth. In other words, let the sound fall into the mic.
  • Always wear headphones to monitor your audio. Everybody that shoots video knows that, but not everyone does it. Nothing is worse then realizing you captured crappy audio and then having to spend way too much time trying to make lamb chops out of ground beef. Ok, I admit  it. I hate wearing headphones. Sometimes I get lazy, but one thing I don’t ever compromise on is wearing them during an interview. You can always fudge your b-roll audio by lowering levels, but rarely can you do this with your a-roll audio.
  • If you’re doing an interview with a subject outside, turn them away from noise like traffic. Shotgun mics tend to amplify the noise from behind the subject.
  • Nothing is worse than trying to edit a sequence with music playing in the background of several clips. The ambient music will jump around like a goldfish on a carpet. Which brings me to the first thing you should do when walking into a room you’re going to record in. Listen. Listen for hums, clock tics (my favorite), traffic noise, music etc. Try to minimize these distractions if you can.
  • Record a minute of room tone. You’d be surprised at how handy it comes in when you’re editing. Need a bit of breathing room between two clips of someone speaking? Room tone to the rescue. 

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