Sound dampening shooting bench.

[k31]

This is one I designed for a gent who lived with neighbors a bit too close some time ago. I own a recording studio and have a good grasp of acoustics.
Materials are simple...... 2x4s , plywood and Auralex http://www.auralex.com
Use at least 3" thick Auralex. The best is the wedge shaped sheets. I buy it in 4'x4' boxes for different acoustic applications. You'll probably want the 2'x4' sheets.
The objective is to keep the muzzle no further than 1/4 of the way into the enclosure. Use your own building skills, but make sure the Auralex covers both sides and the overhead. The two angles at the front are 45 degrees, covered with Auralex and they're important.






P

 

[sefus]

and for the rednecks amoung us, a line of old tires lined up to shoot through. I like the Auralex idea better though

 

[DMK]

Cool idea! Thanks for sharing your plans. I'm always looking for a way to dampen the noise of my backyard range.

How much should a 2'x4' sheet of Auralex cost?

I'm confused about this statement:

The objective is to keep the muzzle no further than 1/4 of the way into the enclosure.

Why would having the entire rifle (or pistol) inside the enclosure be a bad thing, as long as the muzzle isn't too close to the far opening?

 

[k31]

The more Auralex ahead of the muzzle the more sound absorbtion there is.
We buy Auralex by case lots for recording studios so I'm not sure what my office manager pays. I'll find out.

k31

 

[swingset]

I used a section of concrete form (cardboard stuff) lined with 2 layers of convoluted mattress foam (poor man's aurelex) to shoot through. It works great.

If you think about it, a round shape is much better for dampening than one with sides and corners. You want as little deflection and ability for the sound to bounce as possible. A tube.

 

[270Win]

Exactly how much sound absorbtion are we talking about?

 

[Acrid]

The problem is due to the sheer dB at extreme frequencies a rifle makes. Think of it this way....in a studio you run prolly somewhere around 100dB if you got some rock band cranked in there. A -30dB isolation brings it down to 70dB outside the room, a safe level. Now I believe a .45 Colt pistol at 25ft is 140dB, so a 30dB cut wouldn't bring it into a safe range, especially considering sound pressure is a log. So just doing studio dampening wouldn't be enough.

What you'd need is acoustic traps, like those found in a silencer.

 

[270Win]

Any practical way to construct one of those, on a bench, or perhaps a portable version?

 

[k31]

You're right, of course. I really don't know what I'm talking about and none of the shooters that used this design had any luck with it at all. That's exactly why I posted this.

k31

 

[DMK]

If you think about it, a round shape is much better for dampening than one with sides and corners. You want as little deflection and ability for the sound to bounce as possible. A tube.

There's no reason you couldn't put angles in all the corners like K31 did at the front in his drawings.

K31, how much of a DB drop are we talking about with your design?

 

[Drakejake]

This is an interesting discussion. I may be buying some land for outside shooting and the noise, certainly from .30 rifles, would bother my neighbors. If this purchase goes forward, I will need something like what is described. But how much is the noise reduced?

Thanks,

Drakejake