Shotgun for car exhaust audio

T

Trademark

Well-known member
I'm doing a lot of work shooting cars at the moment and my shotgun that I have now is pissing me off a bit because it peaks very easily, especially when I'm pointing it at a particularly loud car. My levels are ok and the intake is never in the red but it still breaks up. I have an Audio Technica 4073 that I paid 600 for.

Maybe my mic is ****ed, wind blasted to hell perhaps, but either way im looking for something that can handle loud exhaust noise without taking a ****.

I've read the stickys on shotguns but they don't mention anything about high noise levels or trying to capture very loud stuff. This is going into my hvx/hpx.

I'm all about investing in the best gear the first time, but if we can keep it under 2k that would be sweet.
 
You might consider looking at what the pros use to record gunshots. Cheap mics may be the way to go, borrow or buy a sm58 and see if that works.
 
The mic is rated at 141 dBSPL without the pad switched on, 151dBSPL with the pad. That should be good for anything this side of a nuclear blast :) I'd suspect that you're overloading the input to your camera's preamp and driving it into clipping rather than overloading the mic itself. Driving the camera recording amps with too hot a signal can't be corrected by turning down the recording gain because the damage happens upstream of the gain controls - all the gain controls can do in that case is make the distorted signal louder or softer but no matter how how soft you turn it down it's still distorted. Try inserting an inline pad between the mic and the input to knock the signal level down a bit and see if that helps. If that doesn't help and you still think it's the mic itself that's the culprit, dynamic cardioids are the go-to mic for very high SPL situations, get closer and give something like an EV RE-50 a try.

Don't get too enamored with mounting a mic - any mic - on-camera. Overall that's one of the LEAST useful, and least used professionally, mic placements. Virtually every ENG camera has one and virtually NONE of them are ever used for anything other than general scene ambience.
 
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If you can't find a good answer here I'd ask the question at jwsound. They'll give you the right answer. They're all pro sound mixers.
 
If the exhaust sound is overloading the mic itself, try backing the mic off a bit. For extreme closeups of very loud vehicles, a good dynamic mic may well be the way to go. I'd second Lambert's suggestion of an SM58. When recording vehicles in extreme closeup, I usually reach first for an Electrovoice 635, although I sometimes add an AKG D112 for that massive sub-bass rumble. If you want to make your recordings even more flexible, record two perspectives simultaneously: a dynamic cardioid a couple inches from the exhaust, and your shotgun mic several feet away. While extreme closeups sound really impressive, medium closeups tend to be more useful in post-production.

If it's a matter of wind buffeting the mic, shoot it from a bit of an angle so that you're not directly in the path of the exhaust itself.
 
Trademark said:
sm58 is a handheld im looking for a shotgun I can mount on camera
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Ah, that changes things a bit; I had been operating on the assumption that you were shooting the exhausts as a effects element.

If you're planning on shooting the footage and recording the sound at the same time, then you'll inevitably be forced to either compromise mic placement and coverage for framing and camera position, or else compromise your shot in favour of dramatic and engaging audio. If you want it to sound as good as it looks, then you'll have to shoot two takes: one for the camera, and one for the audio. Fortunately, marrying the two in post-production is a pretty simple affair.
 
There's no reason one can't shoot the picture and record the sound as separate takes. It's not like dialog where there are lip movements that will reveal fractional second mis-matches. If I see an exhaust pipe on the screen and even see gases coming out in puffs while I hear the engine revving , there's nothing there that will clue me as to whether the sound was recorded simultaneously with picture or not.
 
With a shotgun you are going to clip the inputs of your camera - if you are recording loud car sounds. An SM57 will mount just as easily as a shotgun. The SM57 is a dynamic mic that requites no phantom, and you can yell into it. I'm sure you can find a cheaper mic by searching "SM57 clone". Otherwise you'll need an inline attenuator like this one:

http://www.bhphotovideo.com/c/product/68085-REG/Audio_Technica_AT8202_AT8202_In_Line_Attenuator.html

It may work with your shotgun. You might also try using the camera's built in mics with the AGC on - loud cars is one of the few things that would work on. Or one channel camera mic, one channel shotgun.
 
Steve House said:
There's no reason one can't shoot the picture and record the sound as separate takes. It's not like dialog where there are lip movements that will reveal fractional second mis-matches. If I see an exhaust pipe on the screen and even see gases coming out in puffs while I hear the engine revving , there's nothing there that will clue me as to whether the sound was recorded simultaneously with picture or not.
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for this type of shooting, race cars, cars on open roads flying by me, I cant really set-up another take to get sound perfect, its just me and no sound guy so the mic has to be on camera. If I'm looking for really good audio I'll hook up a G2 lav to the bumper and record it that way.

I guess im just looking for a better shotgun for the loud situations I run into.
 
Chadfish said:
With a shotgun you are going to clip the inputs of your camera - if you are recording loud car sounds. An SM57 will mount just as easily as a shotgun. The SM57 is a dynamic mic that requites no phantom, and you can yell into it. I'm sure you can find a cheaper mic by searching "SM57 clone". Otherwise you'll need an inline attenuator like this one:

http://www.bhphotovideo.com/c/product/68085-REG/Audio_Technica_AT8202_AT8202_In_Line_Attenuator.html

It may work with your shotgun. You might also try using the camera's built in mics with the AGC on - loud cars is one of the few things that would work on. Or one channel camera mic, one channel shotgun.
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will that SM57 do well with a car thats 50 plus feet away? I may try that attenuator with my current shotgun as well
 
Trademark said:
will that SM57 do well with a car thats 50 plus feet away? I may try that attenuator with my current shotgun as well
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Do try the attenuator first. If your current mic has actually been damaged, of course replace it, but unless it has been damaged, I doubt that the problem is caused by the sound being too loud for the mic itself . The spec'd limit of 141dBSPL is one of the highest among shotguns. By comparison, the Rode NTG-3 is 130dBSPL as is the Sennheiser MKH416, the Sanken CS3 is 120 dBSPL, and the Schoeps CMIT is 132 dBSPL. It's output is also fairly high in comparison but thatt's where the pad comes in. Assuming you have a proper shock mount for your mic and proper wind screening so the problem is not actually that you're picking up handling noise, I seriously suspect that it's the mic overloading the inputs rather than the mic not handling the sound levels. Switching the mic's own pad on will cut the signal by 10dB, raising the max SPL spec to 151dBSPL and if that isn't enough, a 10 or 15 dB pad inline would cut it even more. Putting an omni or cardioid - even a shotgun - on your camera to record something 50+ feet away seems to me to be a recipe for recording clear conversation next to you and all your handling of the camera controls while engines go by in the distance background. The inverse square law means you're going to record the kid next to you saying "Look at that, Daddy!" clearer than that racer on the track going by at full throttle 50 feet away. :)
 
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The shotgun is not the problem, the camera preamps are the problem. Switching the pad on the mic in will help as will switching the low end roll off switch in on the mic (if it has one) The overload is probably coming from very low frequency sound from the cars that you don't really hear.
Are you using an external preamp on your camera like a Beachtek? These can help too has they typically have more headroom and give you a poiint for gain adjustment before the camera preamps.
 
If the sound is loud enough the mic will overload mechanically, no amount of padding will do any good. Using a 10 dB pad is still recommended, as it might protect the mic-pre from overloading.

With a shotgun aiming the gun slightly away form the sound source might help, at the cost of non-optimal sound quality (uneven frequency response).
 
Petrus said:
If the sound is loud enough the mic will overload mechanically, no amount of padding will do any good. Using a 10 dB pad is still recommended, as it might protect the mic-pre from overloading.

With a shotgun aiming the gun slightly away form the sound source might help, at the cost of non-optimal sound quality (uneven frequency response).
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The overload point for his shotgun is 141dB spl. Short of sticking the mic up a tailpipe you will not see anything anywhere near that level, and you could not stand in a soundfield that intense without suffering excruciating pain and instant permanent hearing damage. The mic is not the problem. Camera preamps are notorious for having no headroom on the other hand. Condenser mics in general and shotguns in particular put out a pretty hot signal. I use a Beachtek adapter to solve this problem with my GL2.

The suggestions to use a dynamic cardioid type mic are good too. The EV635 is the classic ENG dynamic mic and works well in a broad range of situations.
 
Razz16mm said:
The overload point for his shotgun is 141dB spl. Short of sticking the mic up a tailpipe you will not see anything anywhere near that level, and you could not stand in a soundfield that intense without suffering excruciating pain and instant permanent hearing damage. The mic is not the problem. Camera preamps are notorious for having no headroom on the other hand. Condenser mics in general and shotguns in particular put out a pretty hot signal. I use a Beachtek adapter to solve this problem with my GL2.

The suggestions to use a dynamic cardioid type mic are good too. The EV635 is the classic ENG dynamic mic and works well in a broad range of situations.
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A bit of an exaggeration. Yes if you were in a constant 141dB sound field it would not be good for you but the instantaneous levels can be much higher than the average. 141 dB is about what you get three feet from a riffle shot. The individual exhaust "pops" might well be over the limit even if the average isn't. mix stages get up to this level occasionally.
 
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