Sound decisions

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Film-making is a highly technical undertaking. And while I’m comfortable using a camera, having been a photographer for about 40 years, video is new to me. And it’s new to everyone on the shoot. We’re not just amateurs, but rank beginners, albeit with the desire to learn.

So, making this film is going to be a steep learning curve that I, for one, am enjoying. We’ll share that experience with you.

As we’re shooting on a DSLR, and as all DSLRs have crap sound, we’re going to be doing the classic thing of double system shooting – ie, recording the sound separately from the image. Mostly.

I say mostly because we will be using a Nikon ME-1 mini-shotgun mic mounted on the camera hotshoe. It’ll be there mainly to record reference sound for syncing up later in Final Cut Pro X. But it might prove a useful backup, just in case.

Zoom H4N

Zoom H4N

So, for sound we’ve chosen a Rode NTG-2 shotgun mic (and maybe a Rode M3 cardioid condenser mic for one or two indoor shots) hooked up to a Zoom H4N digital recorder running at 48KHz, 24-bit. We’ve put a shock mount for the mic on the end of a carbon fibre monopod, which is going to be our boom.

The one problem we’ve already run into is that the preamps in the Zoom are a bit feeble. I bought it for recording podcast interviews (see, both in my home studio, where it’s hooked up to a mixing desk, and on the road. In the latter case, I use the built-in mics. And it’s superb for that kind of use.

Running a mic straight into the Zoom, though, results in fairly low levels. Our first experiment was with the Rode M3 mic held about 50cm from the actor on an outdoor test shot. With the record levels cranked up to 85-90% we were still only getting about -20dB. Normally, we’d like to see the levels between -12dB and -6dB. I’ve done some tests since with the NTG-2, with similar results.

Both tests were done using phantom power provided by the H4N. Phantom power is a DC power supply (48V in our case, though 24V is also frequently used) that devices like mixers, preamps and recorders provide in order to power the mic.


FetHead Phantom

So I’ve ordered a FetHead Phantom from Triton Audio. It’s an inline device, runs on phantom power and which passes on the phantom power to the mic. It gives a fixed +20dB boost, which I think will do the job. And its advantage is simplicity. No batteries to worry about. No dials or switches to inadvertently set wrong. One day I hope to be able to afford a Sound Devices preamp, or even better, their MixPre-D field mixer. But these are expensive devices, way beyond our budget for the foreseeable future.

Tom is our sound recordist. Luckily he’s a quick study and is picking this stuff up very fast, so we’re in safe hands there. But we need to find a boom mic operator, to free Tom for the tricky stuff. Last time he was trying to hold the boom, hit the record button and monitor levels all at the same time. And it would have been fine if he’d had another arm and another pair of eyes.

UPDATE (14/07/2013): The FetHead arrived and I immediately ran into a problem. With the M3 mic it works beautifully, and exactly as advertised. The gain is boosted to a perfect degree without increasing the noise to any significant amount. But with the NTG-2 there was an absolute hiss storm.

Many experiments later (changing cables, testing with a mixing desk instead of the H4N and other futile efforts) I discovered the only way to use the NTG-2 and FetHead combination is to power the mic with a battery and the FetHead with 24V phantom power from the H4N. This is slightly annoying, as I’d wanted to avoid using batteries in the mics.

Triton Audio was very responsive, even returning emails on a Sunday. But in the end, we came to the conclusion that there is some weird incompatibility between the mic and the preamp, at least when using the 48V phantom power that the NTG-2 requires.

Oh well, I can live with it for this project. But I see a field mixer in my future…


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