How loud is TOO loud?

R

ryanwaggoner

Member
Hey guys,
 Due to my proximity to the military (I'm in it  :) ) I have a great opportunity to shoot some footage of planes taking off and landing at the Naval Air Station where I'm located.  I'll be about 175 feet away from the planes, so I should be able to get some good footage.  But I'm wondering if my microphone could possibly be damaged by the extremely high volume of the jet engines.  I plan on mixing in sound later in post, so I'm not really after usable audio, but I want to make sure that my mic (the on-camera) isn't going to rupture or something.  Thanks for your help.

Ryan Waggoner
 
Re: How loud is TOO loud?

Use some dynamic mics, or condensors made to handle high SPL's. Some really sensitive condensors can be damaged by high SPL's.

-Dave
 
Re: How loud is TOO loud?

and please do protect your ears!!!!
A mic capsule can be replaced easily but an eardrum can't!!!
We have been recording sound from fighter jets taking of recently
and we used very sensitive Schoeps mics, still no problem.
SPL 175 feet from the aircraft should be up to 140 dB during takeoff
which can be handled by most condenser mics.
 
Re: How loud is TOO loud?

thanks joachim and dave. I'll be sure and use adequate hearing protection (actually, they won't let me out there without it :-) ) and I'll hopefully post some great footage soon...

Ryan
 
Re: How loud is TOO loud?

Ryan,
what aircraft will you shoot? F/A 18s or F14s ?
At which Naval Air Station? I have been visiting Miramar once.
 
Re: How loud is TOO loud?

DPA makes some mics specifically made to handle up to 168db of spl's. If you can get your hands on those, try them out. They sound fantastic.

-Dave
 
Re: How loud is TOO loud?

OK, this is going to sound silly, perhaps, but... Whether or not you use the mic on the camera, isn't it still there being hit by the sound?

Sorta like "Yeah, there's a jet taking off 20 feet away from me, but my ears won't get damaged because I'm not paying attention to it."?

Dan
 
Re: How loud is TOO loud?

[quote author=GenJerDan link=board=audio;num=1090267015;start=0#6 date=07/21/04 at 23:36:03]OK, this is going to sound silly, perhaps, but...  Whether or not you use the mic on the camera, isn't it still there being hit by the sound?  

Dan[/quote]

Dan:

yes, you are right. If the mic's diaphragm would have been "injured" by the hight SPLs using the mic, it would still be injured if it were still there and not being used. The mic diaphragm is like a piece of tissue paper stretched across the top of a glass jar. Sound is air molecules moving at various velocities colliding with other air molecules. Higher SPLs mean the air is moving at a higher velocity. Which means the air hits our piece of tissue paper with more force. More sensitive mics would be represented in our example with thinner tissue paper (3 micron, gold sputtered tissue paper in some mics). If the paper is too thin it can rip the diaphragm.

The reality is, even condensors have to be hit with very hight SPLs to damage them. Some mics like ribbon mics are damaged more easily with hight SPLs.

If I were doing this shoot i'd use a dynamic mic as recommended above. And if i were really concerned for my on-camera mic I'd remove the mic elements (removing the screws) CAREFULLY, and leave 'em at home.
 
Re: How loud is TOO loud?

Y'ok.  Just checking my thinking...I'm heavily into NyQuil at the moment, and...well...my cognitive abilities may have been off.

Anyway, I may be doing the same sometime soon.  I'm gonna check with the Public Affairs Office at Ramstein and see if I can shoot some stock of C-17s or C-5s from the end of the runways.  Nice dramatic shots.

Assuming I don't chicken out, that is.  And I don't fall on my ass doing the tilts.

Dan
 
Re: How loud is TOO loud?

LOL, Dan. I'm actually shooting down at Naval Air Station Sigonella in Sicily. I got a few good shots yesterday, although I had problems with getting a smooth pan...need practice, I guess. Ramstein is a busy field, you should be able to get some good footage. The footage I'm shooting is destined for a DVD that will be sent out to people being stationed here.

Thanks for the tip gossamer...I understand how mics operate and that's why I was worried about the on-camera. I hadn't really considered taking it off, but I thought about wrapping some kind of padding around it to block some of the sound. It wasn't too bad out there, so I think it'll be ok. Even if it does get damaged, it's not the end of the world. I probably won't ever really use the on-camera for anything, anyway.

Thanks for your help guys!

Ryan
 
Re: How loud is TOO loud?

Ryan.

If you're considering wrapping the mic (good idea, better than removing as you have less chance of losing parts) just remember that sound is air. If you blow through something and can feel your breath coming through the other side (like foam) then it won't do a lot to block SPL.

The ideal material would be an airtight or nonbreathable fabric or thick plastic bag. I have this nylon backpacking stuff sack I use which is waterproof and airtight (it'll float) that would be ideal.
 
Re: How loud is TOO loud?

I had a pair of headphones where I lost the foam pads. Like a moron I thought putting some duct tape over it would be a nicer feeling than the plastic. Let me tell you, that stuff is a pretty good insulator.

I bet gaffers would do the same thing, and would come off cleaner.

~Andrew
 
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