Helping Out My Friends New Gun Club

[Syncamorea]

No pun intended, but there probably is no magic bullet fix. The steel plate in the shooting zones provides some degree of safety but is bound to be part of the problem for the shooters since it's reflective and pretty rigid. And there's not a bunch of space in the shooting spots to add absorption over the steel.

If the owner can invest in treating the walls, broadband absorption with some air gap to the wall should have a measurable effect. Say 6" of attic insulation with a 4-6" air gap - thicer is better if there is space. I'd cover every possible square foot. Limp mass vinyl bass traps, VPRs, anything to take down the reflection of the gunfire will help matters.

The zone directly behind the shooter should be looked at closely for trapping opportunities. The area that reflects from the muzzle to the ear on those steel plates also. If they could afford the space to put in absorption there, it should have real benefit.

On the other hand, adding silencers to the guns would have a huge effect!

[gullfo]

also consider the material - lead can collect in the covering so it may be that these absorbers should be removable and have the cloth covering removable (like a zippered pillow case) so they can be cleaned periodically. coloring should be neutral and non-reflective. 1"-2" thick should suffice. scattering them around the side walls, ceiling, and behind the shooter lanes will help the overall noise level.

[KennyS]

Hey thanks for the responses! Which insulation would the best bang for the buck? Haha. I figured high density like 703? Or 705 I don't remember which would trap the lower frequencies better.

Cheers and thanks,
Kenny

[avare]

Originally Posted by KennyS

Hey thanks for the responses! Which insulation would the best bang for the buck? Haha. I figured high density like 703? Or 705 I don't remember which would trap the lower frequencies better.

Gun shots do not have significant energy at lower frequencies. For low frequency absorption the best vakue is depth, assuing you have the real estate. Use 3 lb/ft³ glass insulation or 4 lb/ft³ mineral wool. 4" thickness minimum.

Enjoy!

On target,
Andre

[DAH]

Originally Posted by avare

Gun shots do not have significant energy at lower frequencies. For low frequency absorption the best vakue is depth, assuing you have the real estate. Use 3 lb/ft³ glass insulation or 4 lb/ft³ mineral wool. 4" thickness minimum.

Enjoy!

On target,
Andre

Andre, I do not know whether it was due to the room response or the sound itself, but I FELT quite a powerful low-frequency impact with my body while I was standing in 2 meters from a .308 carbine being shot-in in a 150 feet shooting range with brick walls.

[Syncamorea]

It varies gun to gun and no doubt how/where the frequency response is measured. I've seen plots that show the low frequency for a .308 to be a major component of the gunshot sound - and I've also seen a plot for a 9mm pistol that had the LF over 30 dB down from the midrange.

[avare]

Originally Posted by DAH

Andre, I do not know whether it was due to the room response or the sound itself, but I FELT quite a powerful low-frequency impact with my body while I was standing in 2 meters from a .308 carbine being shot-in in a 150 feet shooting range with brick walls.

There is a difference between the sound of an explosion, which is what a gunshot is, and the blast from an explosion. If you have thought about criticaly what you heard and felt when a bomb went off near you, mostly what you noticed was the blast moving you. The "sound" was actually quite low in comparison. The spectrum of M-16 and M-60 guns with out a silencer are shown in blue in figs 16 and 17 of the attached document.

And some people think good studio design is limited to studio sounds. It goes well beyond that including understanding of noise and architectural design etc.

Explosively,
Andre

[Syncamorea]

Originally Posted by avare

If you have thought about criticaly what you heard and felt when a bomb went off near you, mostly what you noticed was the blast moving you.

I'm glad to say I've never had a bomb go off nearby!

Or does a flash pot count?