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Shotgun vs. Hyper, deeper dive


Ben C

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Hey all!

 

Apologies is this feels beaten to death, but I have a question about indoor mic technique. I'm pretty well-versed in the arguments for using a shotgun vs. a non-shotgun indoors. But I've been thinking lately about the effect of distance on the signal-to-ambient-noise ratio. With a shotgun mic, the capsule is inherently farther away from the talent, since there is an interference tube between them. So is the off-axis rejection of a shotgun mic really that helpful when a hypercardioid capsule could be 6-8 inches closer?

 

Thanks,

Ben

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That's not quite how it works. From the physics standpoint you also have to consider how the wave front travels and gap refraction. You can probably figure it out yourself if you understand how wave physics in medium fundamentally work. But I'll leave you with a thought experiment:

Assume you have two microphones, one omni and one that has a pickup pattern of a perfect cylinder. Except for reflection from directly behind the sound source, what other reflections would the second microphone pick up? What difference would distance make to the sound picked up by the second microphone, compared to the first microphone? (Hint: there are two key differences.)

 

Practically speaking, as you are aware of the arguments of interference tube mic vs. not, I don't need to tread any of that ground.

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With a great boom op, the capsule will be further away from the talent - or with a hyper perhaps angled brilliantly away from the worst reflection. But there are also occasions out of doors where a hyper might do a better job than a short shotgun. Sure, it's physics, but it's also plain mic technique.

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Yes. Inside, where you may be dealing with room reflections, closer is quite often better (unless you have a weird reflection problem) and the interference tube is not your friend for that reason. OTOH, the Sanken CS3e's element is at the tip of the mic, not at the base of what looks like an interference tube. It's a completely different design. And, yes, a CMC641 supercardioid with proper wind cutter does a fine job outside. 

BTW, an interference tube shotgun mic can be a poor choice outside if there's enough ambient to the side. The polar pattern of shotguns is sharp for HF, but a lot wider at mids and lows. You'll hear them on  a "car-by" at 90 degrees. 

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Generally speaking (there are always exceptions), a shotgun or short shotgun is more effective for exteriors (because of no reverberation) or large interiors with high ceilings and little reverberation. Cardioids and supercardioids are often better for interiors, particularly when the walls are close and the ceiling is low.

 

Regarding the CS-3e: There are actually 3 capsules (thus the CS-3) They are in an array, and combined in such away to give it its unusually large amount of low freq off-axis rejection. Most other shotguns become more omni directional at the low end of the frequency response.

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