Audio overload while tapping at Gun range

DWhitevidman wrote on 3/24/2011, 5:30 PM
Could I once again lean on those of you with much more experience than I for an upcoming shoot, literally?

I need to shoot footage for a "Gun Training" video. This will include footage of weapons, pistols and rifles, being loaded, cocked, aimed and then fired. It seems to me that no matter if I leave my camera in auto or set the gain manually, I'm going to get a large overload distortion at the time of the weapons being fired.

How might I go about preparing for this situation?


musicvid10 wrote on 3/24/2011, 5:37 PM
Are you determined to use on-camera audio?
You could take an H4, turn down the mic sensitivity (and probably the recording gain) and get fairly good results.

Other approach would be to take a pair of high SPL, low output dynamic mics (think SM57) into your camera on manual gain (AGC will never catch the spikes in time).
ChristoC wrote on 3/24/2011, 5:53 PM
Definitely use a separate mic/recorder with gain set manually.
Remarkably, often you get a more realistic gunshot sound by pointing the mic away from the subject, e.g. towards the ground.
richard-amirault wrote on 3/24/2011, 6:13 PM
OR .. just use an external recorder .. as described .. but only use the audio from that for the shot(s) only.

In other words ... mute the gunshot audio on the camcorder track, and raise the level on the (otherwise) muted digital recrorder track .. just for the gunshot.

That way the camcorder will get all the "normal" sounds and the digital audio recorder will only be used for the gunshots themselves.
DWhitevidman wrote on 3/24/2011, 6:15 PM
Thanks for the replies, If I'm finding the correct H4, it's probably a little prices for me. I'm going to get $250 for this 20 min video, so maybe an external mic aimed at the ground and away from the shots will be best. Guess I'll have to try some tests first.
richard-amirault wrote on 3/24/2011, 6:23 PM
OR .... mute the audio from the camcorder (when editing) for every shot .. and just use a sound effect of a gunshot?
musicvid10 wrote on 3/24/2011, 6:24 PM
If your camera has xlr inputs, you should be able to get someone to loan you a pair of sm57's for free (like a band or a nightclub or music store). Any condensor mics except pricey drum mics are going to be too sensitive for your shoot.
richard-amirault wrote on 3/24/2011, 6:27 PM
Actually, wouldn't a single dynamic mic work? There would't be much of a stereo effect at that distance / level. Obviously put the mono track on both sides of the stereo track in post.
ushere wrote on 3/24/2011, 6:43 PM
few years ago i did something similar - pd 170 on camera shotgun turned right down to (i think it was 2 or 3). sounded perfect, though almost everything else other than the gun fire wasn't picked up. (not that it mattered)
Dave_OnSet wrote on 3/24/2011, 7:54 PM
Quite a while back i was doing audio on an interview show where part of one of the interviews took place between two people trap shooting. I was a little worried, but needed all the dialog in between the gunshots, and had both people (Jackie Stewart and George Plimpton, I believe) on wirelesses - at that time I had Vega systems with Tram mics. Surprisingly enough, the transmitter limiters kicked in so fast on the gunshots, that all you really heard was the echo coming off the canyon walls. The interview dialog was great as long as it didn't happen during a gunshot, and they just added some gunshot fx in post. (I recorded some wild fx separately with a dynamic mic.) It all worked out surprisingly well!
musicvid10 wrote on 3/24/2011, 8:21 PM
"the transmitter limiters kicked in so fast on the gunshots,"

That wasn't actual limiting, it was the RF carrier's inability to fully modulate the AF spike; a bit analogous to the "soft ceiling" when recording to analog tape. In certain situations it can be a blessing.
Tim L wrote on 3/24/2011, 8:55 PM
Although ushere came close, I'm surprised no one so far has directly suggested:

"You need a shotgun mic for that..." ;-)

Rather than using a separate gunshot sound effect, maybe record video with audio set to pick up the dialog, then at the end of the take adjust your audio levels down and have them fire off another shot or two just for the audio. That way you'll get the correct gunshot sound to match the particular weapon.

(I'm pretty sure gun enthusiasts would know if the gunshot sounds weren't authentic, just the same way motorcycle guys would know if you dubbed in audio from a different type of motorcycle compared to what appears onscreen, etc.)
DWhitevidman wrote on 3/25/2011, 7:13 PM
Thanks for the additional suggestions. I don't have XLR inputs on my Sony VX2100 and the sound isn't extremely important, I just don't want an overloaded sound. I'll have a cooperative team I'll be taping, so with some initial testing, considering the options presented here, I'm confident you've given some good background and how to approach this scenario. Thanks to all.
Serena wrote on 3/26/2011, 4:28 AM
You want all of the audio of loading, cocking, firing clearly and at representative levels. My approach would be to shoot each of these separately (as separate SFX for the weapon involved) then shoot the complete sequence. In post mix each SFX into the sequence. This will enable you to set the appropriate audio levels for speech etc whilst having full control over spot SFX. Doesn't need to be said that an AGC will clamp down after a gun is fired, which must be avoided.
baysidebas wrote on 3/26/2011, 8:42 AM
If you're shooting tape, there's yet another effect to be aware of. Depending on firearm and distance to camera, the shockwave can affect the tape transport and result in image breakup. Some years ago I was taping the firing of a 44 Magnum with the camera about 6 feet from the gun. Every shot resulted in the image breaking up due to the physical effect of the shockwave. So test before you commit.
farss wrote on 3/27/2011, 1:20 AM
Watch out for people with guns with compensators.
I've been trying to figure out why some pistols are way louder than others and it just dawned on me. There's a couple of people in our club shooting 38 Super and the blast from their STI Grandmasters is way louder than every other pistol. They're the only pistols in the club with compensators. They are really loud, loud enough to damage a mic I'd think.

ushere wrote on 3/27/2011, 1:41 AM
bob - what time zone are you posting from!?

ok. same one as i am - so where are we? daylight saving or something?
JJKizak wrote on 3/27/2011, 5:21 AM
I would find out how they recorded the gunshots in the movie "Shane".
farss wrote on 3/27/2011, 5:58 AM
"so where are we? daylight saving or something? "

Daylight saving ends 3rd April, don't jump the gun.

Serena wrote on 3/27/2011, 9:46 PM

Muzzle brakes, as I know them. But I see they also go by the name "recoil compensators", and Wiki tells me that in pistol competition they're just known as you named them. Whatever, they work by directing propulsion gases sidewards/backwards and consequently the muzzle noise. Yes, definitely require ear protection and a robust mic. In films/TV gun shots are usually foley.
Marc S wrote on 3/28/2011, 12:09 AM
I shot a training video last summer for pistol, shotgun and rifle. I did record seperate audio during parts but the on camera microphones actually did pretty good. I did a lot of taping following the shooter close behind with a Sony MC-50 and the gun shots sounded pretty good from the onboard mic. You might want to do some testing. The cameras seem to clamp the shot quick enough.

Here's a sample. I believe the editor ended up using the on board sound for most of the shots. The over the shoulder stuff is MC50. Other cameras were Z1s and a Canon A1 with shotgun. There was also audio coming through the lavs which sounded good as well. From what I remember I think I used the limiter on the Z1s with auto audio. If you can do some testing you may find you are happy with the camera audio.

I wore ear protectors that had built in mics. Whenever there was no shooting you can hear fine. As soon as guns start firing it clamps the noise, This was helpful. Also make sure everyone involved in the shoot is practicing SAFETY-SAFETY-SAFETY. No shot is worth getting shot. Good luck!


Serena wrote on 3/28/2011, 3:44 AM
The gun shots are lacking presence, especially the automatic rifle. Nevertheless they serve the purpose and in a training video that is sufficient.
JJKizak wrote on 3/28/2011, 4:52 AM
The gun shots recorded in Shane were the best I have ever heard bar none.
Marc S wrote on 3/28/2011, 8:14 AM
"The gun shots are lacking presence, especially the automatic rifle. Nevertheless they serve the purpose and in a training video that is sufficient."

Well said. While not "Shane" or "True Grit" quality, for training purposes it's still better than what the shooter hears through his ear protectors and serves the purpose. The hassle of replacing every shot would not be worth it in my opinion. Most viewers will not care.

I was just surprised at how well the cameras I used handled the gun shots. I did a fair amount of pre-testing to figure out the best settings which I recommend if you go this route.
DWhitevidman wrote on 3/29/2011, 7:49 PM
Update: I am going to take some test footage on-site the day before the actual training shoot.

The group I'm taping and making the video for is the local Sheriffs department and officers are the shooters, so all necessary safety precautions will be taken and followed.

I post some feedback this weekend as this Thurs & Fri is the test and then the shoot.