Workflow suggestion for external audio in video production?

Special Interest Groups Audio Processing
1

Hey everyone—

I have been into video production for quite a while and finally decided it was time to upgrade my sound equipment. I now capture my audio completely separate from my video and sync it up in post-processing.

I am using a Tascam DP-800EX as my field recorder, and a Rode NTG-2 as my primary microphone.

I recently did a shoot where the talent was stationary in a chair. I had the NTG-2 on a boom pole and it was placed probably about 18-24 inches away from her mouth, just out of the video frame. IIRC, the built-in high-pass filter on the mic was off.

I had it wired into the XLR input on my recorder. The recorder was set to record at “high” and my trim for the input channel was nearly as loud as it goes. It was loud enough that I could hear a fairly significant amount of hiss even as I was recording. The indicator on the screen showed that I was peaking at around -12dB (which, as this noob understands it, is about right?).

Upon getting home, I started cataloging the video clips, matching the external audio and getting ready to make the first rough cut. The audio from the DSLR’s built-in mics sounds like normal, crappy, audio, but the volume levels are good. The audio from my external setup sounds much better, much cleaner, and MUCH quieter. When I amplify it in Audacity, I get a lot of loud noise. When I remove that noise using noise removal, I have to choose between leaving a lot of hiss, or cutting out all the hiss at the cost of making the dialog I wanted to actually keep sound tinny and weird.

I can’t seem to get my signal-to-noise ratio where I expected it for equipment this nice. Actually, I can’t even seem to get it to the point that it’s usable as external audio for my video production.

I really know my way around the video world, but I’m pretty new to the audio world. I’m convinced that it’s something to do with my workflow or capturing technique, rather than my equipment not being good enough for a setup this basic.

Does anyone see any glaring errors in my setup, gear choices, workflow… etc.? Or failing that… what kind of tools would you recommend to clean up my audio and boost the volume levels to being usable?

2

A bit on the low side. We normally recommend that you aim to peak at around -6 dB.

How did you power the mic?

3

For this shoot I powered the mic with an AA battery. The mic can also run off 48v phantom power provided by the DP-800EX.

4

If you use the internal battery, can you turn Phantom Power off? You can get a conflict (not likely with that microphone).

These are the hard ones. If somebody forced me to design that shoot, I’d be doing what you did.

You can’t get rid of hiss in post. You just can’t. Noise Removal works by carefully designing filters to remove objectionable noise. Hiss is white noise which has all frequencies, so Noise Removal tries to remove the whole show.

You can try Effect > Noise Gate.

I’m more concerned why the shoot seemed to require extraordinary settings. This is the show your microphone was designed to shoot. I need to look up your mixer.

You did have a fishpole operator, right? These are not the easiest microphones to aim particularly at high direction setting. Is this the mic that comes with two speeds by changing its nose?

Koz

5

The recorder was set to record at “high” and my trim for the input channel was nearly as loud as it goes.

Where is this “high” setting of which you speak? I would have picked medium volume or low volume to make the preamp give me more Zot (technical term).

Also the A Volume and the Channel 1 Volume should have worked at about 3-o’clock. Correct me, but both affect the recorded volume, right? You should avoid cranking one up in favor of the other. Sneak them both up if you have the option.

I’m guessing about some of these settings and adjustments, but any recording system still has to pass Microphone Recording 101.

The goal is live recording with peaks around -6, but your show should have worked. It’s well within the permissible range.

Something’s wrong.

Koz

6

Aside from various volume and trim knobs, the recorder has a digitally selectable input mode for each input channel. You can choose to use the internal mics, external “low,” external “mid” or “medium” or something, or external “high.” I think there’s also an option for line-in if you’re recording an electric guitar or some such. Anyway, I used “high.” Also… what is a zot?

As far as I understand, the only knob that actually affects the input volume is the “trim” knob for channel A. The volume knobs for channels 1 through 8 affect playback volume only, as does the “master” volume knob, and the headphone output volume knob.

Good to know about my new target peak volume of -6dB. But like you said… I wasn’t too far off. I think part of the problem is in my recording settings… and perhaps even more of the problem is in my noobish post processing.

Anyone want to offer up their workflow for taking a WAV file and getting it ready to sync to a video track?

7

Step 1:
Find out why I’m getting such a weedy signal from a shotgun microphone that is 18 inches away from the mouth of the person speaking.
Until that is resolved there is no step 2.


I hate it when they label inputs as “high / medium / low”.
Do they mean “for a high level signal” or do they mean “high gain (for a low level signal)” ?

What happens if you change the setting to “medium external” ?

8

That’s a good point - will run some tests with the input mode set to various settings (high, med, low). Could be I had it set to “high” and the recorder thought that meant my signal was high so it would have to trim it down.

Thanks for the help so far everyone.

That being said, I have audio now from the shoot that I’m having a lot of difficulty processing. What do you recommend for getting the signal-to-noise ratio where I need it?

9

My recorder says “Low” when you are expected to record low level sounds. It has the highest boost to the microphone signal.

Koz