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-   -   Can the on camera mic be damaged by gun fire? (https://www.dvinfo.net/forum/canon-xh-series-hdv-camcorders/483225-can-camera-mic-damaged-gun-fire.html)

Dan Lambert August 11th, 2010 09:28 AM

Can the on camera mic be damaged by gun fire?
 
I have a friend that is an attorney, but his hobby is shotting various guns at his outdoor range. They have a competition called "The Cowboy Shoot" where they have a bunch of building resembling the wild west days. I'm not sure how the scoring works or anything - guns are not my thing.

He was wanting me to shoot some video of one of there competitions, my only concern is weather or not gun fire might damage the mic?

I'm thinking I could probably stand back a good way and just zoom in on the action to I'm not right next to rifles being fired.

And thoughts much appreciated.

Dan

Edward Carlson August 11th, 2010 10:44 AM

Only if he's aiming at the camera!
No, gunshots won't damage the mic, however the high SPL might cause distortion and clipping.

Dan Lambert August 11th, 2010 12:44 PM

@ Edward Carlson

Thanks!

Shaun Roemich August 11th, 2010 01:41 PM

Wear hearing protection yourself, though!

Allan Black August 11th, 2010 04:12 PM

Dan, getting a balance so the gun shot doesn't distort then you can hear the following dialogue will be difficult .. and your friends will want to hear what was said after each shot.

I suggest if you have an A1, zoom in on the shooters and set your record gain on the dialogue and let the gun distort, then replace it in post with another gun sound. With an A1s put the audio limiters on and do the same.

In fact the best way to do this is to employ 2 cameras, one on the shooters, the other framed on the targets so you can cut between them. The guns will probably sound like twigs snapping, so if you want to impress them, look around for some free fx.

For shotguns we'd use a 4" naval gun, aim high and don't forget to dress the part :)

Cheers.

Kevin Currie August 11th, 2010 11:48 PM

When I made my first movie, nobody actually fired any guns (way too much red tape and $$), and even most of the shots were off-screen. But I wanted an accurate sound fx, so I set up a mic and a real gun (firing blanks) in my small basement. I was nearly deafened and all the mic caught was a tiny pop. Lessoned learned LOL

Sorry, that doesn't help you at all, but the question brought back that memory.

Peter Moretti August 12th, 2010 12:46 AM

Dan,

I would post this ? in the audio sub forum. I don't believe outside gun shots will cause damage to your equipment. But I have heard of loud screams blowing out mics. So I imagine there is some merit to your concern.

Peter Manojlovic August 12th, 2010 09:58 PM

Yes, i am concerned about this myself...
I filmed an event near speakers with heavy bass....

Something must have happened.
Since then, my mic has always been clipping near larger speakers...I can verify this, because the second camera (XHA1) didn't have the distortion issues that i had....

I hope your on camera mic isn't damaged...

Paul R Johnson August 13th, 2010 02:10 AM

A typical electret condenser capsule has an air gap between the diaphragm and backplate of 20μm or so - a fifth of the size of a human hair. The virtually permanent charge is between 200-300V is supposed to last the lifetime of the microphone. It's perfectly likely that the over pressure can deflect the mylar enough to short out, but oddly, the only information on the net is in the form of apocryphal forum links, usually "well respected Mowtown producer .... or people who had failed microphones when recording gunfire. I expected to be able to find some scientific data, or manufacturer comment, but I failed. No primary verifiable data at all.

So my own conclusion is that the physics suggests damage could occur, but nobody seems to have actually tested the symptoms to generate an accurate diagnosis of an actual fault.

Don Palomaki August 13th, 2010 03:57 AM

A gunshot provides a high pressure impulse and muzzle blast. Very loud up close and forward of the muzzle. If you are in an enclosed area (e.g., in a room or alley) it will be louder. The chance of damage (due to the sound level) will depend on how close the mic is, the mic type/construction, the type of weapon, how confined the area is, the sound damping properties of the venue, and the direction the muzzle is pointing relative to the mic.

If the camcorder mic is built-in, be careful to stay some distance from the muzzle. I suspect, but cannot confirm, that using something like a kick drum dynamic mic that is designed for high sound levels might work best for gun shots, but not very well for voice.

If you need the live shot sound, run some tests before the money shoot.

As note above, your best bet for "satisfying sound" is to add effects for the gun shot in post.

Alex Chamberlain August 13th, 2010 03:06 PM

Dan, I actually produced a video very similar to this a while back. I used a couple of Azden Shotgun mics and neither sustained any damage, despite the Rifle Range portion being recorded beneath a baffle that actually amplified the sound. Here's a link if you're curious as to how close my camera was to the firearms (quite close).

YouTube - Southern Utah Shooting Sports Park

(Disclaimer: Before you think I'm irresponsible, for several of these shots I setup the camera on a tripod, left it rolling and then got behind the line of fire before anyone approached the range.)

G. Randy Brown August 21st, 2010 03:13 PM

Not to hi-jack but I wonder if 100 mph plus wind (camera above windshield in a convertible) could damage the mic

Allan Black August 21st, 2010 05:21 PM

GR on some real cheap mics, yes.

But you'd only position the camera/mic there to record .. and you'd have to install adequate wind protection on the mic and that would protect it from wind damage.

And it would have to be very serious protection, I'd wind a big woollen sock around the camera.
Cheers.

Robert Turchick August 21st, 2010 05:43 PM

Not a hijack at all. They could be probably won't be damaged by 100 mph wind. Ive mounted many camcorders on my
Motorcycles without wind protection and gone well over 100mph (on a track) and mics were fine. The sound was unusable of course but I knew that going in.

As for the gunfire, distance is your friend. With my experience recording all types of things with some very expensive mics, I have not damaged one yet. Just be smart about it. For most gun shots, I'd say you're good outside of 10 feet which gives you plenty of room to zoom in for a closeup.

I did a recording for the Fort Ticonderoga annual tatoo many years ago and the main mics were U87s on the ground level of the fort and an "ambient" pair of 414s up on the fort wall. They neglected to tell me an eight-pounder (cannon) was going to be fired in the fort about 20 feet from the neumanns. Too big a crowd and not enough time to move the mics, I thought about the $5000 I was about to spend to replace the mics. To my surprise, they handled it flawlessly and I have the coolest cannon sound ever!

I have also used 414s on snare drums in the studio about 3 inches from the head. No issues. BUT a friend used to work with Brendan O'Brien who engineered the Black Crowes among many other big artists and said Brendan's favorite mic for snare was the Neumann KM84. They would last about a song before be destroyed. Sad.

Every mic has different spl ratings but the ones on camcorders seem pretty durable.

G. Randy Brown August 22nd, 2010 06:58 AM

Thanks guys


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