range noise & decibel meter

[Czech_too]

First some backround info -
At the one range I belong to, I'm a trustee & the property is leased.

The relationship between the club & the property owners is not the best, so in the interest of possibly improving that I've been toying with the idea of putting up some sort of sound absorption material(s)
whether it be foam insulation board and/or carpeting under the existing roof & the back side of the firing line. Cost is also a factor here so the less expensive ...

Before I go ahead and do the whole firing line, I'd like to do a small area of the firing line first, say 10' wide & take sound readings before & after any materials are in place.
I'm going to need proof that this is a worthwhile 'improvement' before I put it before the board and do the whole line.

For starters, any suggestions on a decent, $30-100, decibel meter?

Brian

[Ickisrulz]

If you didn't know this, you will need a noise meter that measures impact noise rather than steady state as gun fire is an impact. So make sure whatever you buy can be set for impact (impulse) measurements.

[Minerat]

I don't know a source of a decibel meter and know just enough about measuring sound from sand and gravel mines to know that the scale that you use is the most important. Also most meters you find at radio shack work for indoor sounds but may not be the best for outdoors uses. We usually hire it done since it is a specialized science. Sorry for not having more info, I'm just knowledgeable to be dangerous.

[matrixcs]

I think you may be way too low for a decibel meter that will tell you anything. The cost of a meter to measure the short duration of a gunshot will cost dramatically more.
I attempted to get some kind of measurement using an iphone app and it told me nothing ... the sampling rate on even $100 dedicated units will miss the real noise of a gunshot.
The best advise is to look to see if you can rent one of the $2000-5000 meters.

[dragon813gt]

Might as well use an app for the price you're looking at. You aren't remotely close to how much you'll have to spend. Decibel meters are specialized equipment and cost accordingly. We used to hire a company to take measurements before and after we replaced industrial equipment that was close to residential homes. This way neighbors could complain but had no ground to stand on.

[Czech_too]

Yeah, from the bit of reading that I have done, I got the impression that meters on the low $$ side would not register the actual shot but rather the 'echo' of such. And then there's the calibration.
When I saw that Amazon has some listed in the lower , $30, range I thought...
but I'm not paid to think anymore!

I'll ask around the club membership, maybe someone will have such an instrument available.

Brian

[jcren]

Check with local school bands to rent of borrow one. Also, around here anyway, oil and gas companies may have one.

[Smoke4320]

any phone app will be a waste of time

[starnbar]

The thing can be looked at in a number of ways when the S.O. I worked for built a range there were complaints about the night shoots we used to do for qualifying. they finally went to a 45 foot berm around the range and you could hear the shot but it sounded like it was a half mile away. I don.t know if there is a material that will absorb the noise baffles will help but they are more directional than noise cancelling.

[Artful]

http://www.dkenourgios.gr/dk-proionta_shooting_Shooting-Ranges_eng.html
The first Dozen Feet are the most important to control /direct the sound
http://www.dkenourgios.gr/images/Ballistic-Baffles-And-Guard.jpg
http://4.bp.blogspot.com/-YWgqoHldmfI/TkSKf9_ZRjI/AAAAAAAAAYI/DR5adMJdYWw/s1600/club+member+ready+to+shoot.jpg
https://usercontent2.hubstatic.com/13279267.jpg

http://www.allnoisecontrol.com/Industrial-Noise-Control/Noise-Control-Blankets.cfm

http://stopthesound.com/pinta-acoustics-sonex-illbruck/

https://www.nssf.org/ranges/rangeresources/library/NSRS/04PolicyTrack/SoundAttenuation.pdf

https://skyaboveus.com/hunting-shooting/Shooting-Range-Sound-Reduction

http://files.dnr.state.mn.us/destinations/shooting_ranges/outdoor_shooting_best_practices.pdf

http://www.sccoplanning.com/Portals/2/County/Planning/devrev/LARGC_NoiseMitigation_Report_2.pdf?ver=2012-12-18-093940-837

http://bcwf.net/files/Noise_Mitigation_Implementation_Version_1_0_dated_ 18_April_2016.pdf


https://www.youtube.com/watch?v=A5AlH65uT2M
part 2
https://www.youtube.com/watch?v=FG878n3xBts

http://www.actiontarget.com/wp-content/uploads/2015/08/Tactical-Ceiling-Baffles-05-e1455058228252.jpg

Depending upon your clubs use you might set up one or two stations and require they be used first
http://weaponsman.com/wp-content/uploads/2014/07/non_portable_noise_reduction.jpg
http://img.photobucket.com/albums/v30/Turborex/barrel.jpg (http://smg.photobucket.com/user/Turborex/media/barrel.jpg.html)
http://i243.photobucket.com/albums/ff132/orchidman_album/suppressor2046.jpg (http://s243.photobucket.com/user/orchidman_album/media/suppressor2046.jpg.html)
Sound baffles down range [ http://www.nzha.co.nz/?page_id=22 ]
http://www.nzha.co.nz/wp-content/uploads/2015/02/range1.jpg

If your shooting metal targets - attach putty to back to deaden the ring

Your best resource will be your fellow club shooters.
The guy who is in construction can help you get used / waste wood
the carpet layer can get you used carpet
the guy who works retail can help you get packing materials
All of this can effect sound absorption / redirection

[popper]

I used them at work for some medical equipment, even the high $ don't work well for impulse noise. Any inexpensive audio (guitar center type) will work but place it 100 yds or so at several locations around the range. Then you play back into a software analyzer program to get DB (relative). I assume your concern is DISTANT noise, not ear protection. The concrete pipe/baffle system is the least expensive/most efficient system. Local PD indoor range is 1 1/2 mi away, still hear it on certain days. Local public range rifle shots can be heard 2 mi away and are still loud. Cheap packing spiky foam works but longer spikes work better, but less durable. Pipe helps with people using ported guns too - for adjacent shooters. spray on polyurethane foam coating under the corrugated roof will help but must be over covered with butyl rubber to prevent deterioration. Angled baffles work but $$ and maintenance. Spacing should be reverse log, not linear.

[country gent]

Carpeting (Shag is better), egg crating, foams , angled surfaces all help to deaden noise. For years we had a 400 yd range between 2 corn fields. When the corn was up and to full hight and leafed out good the 2 neighbors 1/4 mile away couldn't here the gun shots from my m1As. The standing corn brofe up the noise waves and directed the remaining up. Soy beans weren't near as good not as tall to contain the noise waves. Also on an out door range you need a material that small animals and or insects aren't going to burrow, nest, dig in and tear up. Actually strips of canvass tarps 8"-10" wide every 8" should go along ways to deadening noise. Concrete floors reflect a lot of noise concussion as do hard walls.

[David2011]

Good luck! I live in an area where trees are few and far between except in peoples' yards. I can hear rifle shots at my house which is 3.8 mile straight line from the rifle firing line. The dragstrip is 2.6 miles away and I can hear the cars run.

Would planting shrubbery that grows to 6 feet or more be an option?

[NavyVet1959]

The cheap handheld meters or phone apps might give you an indication of relative *change*, but they are not going to be accurate for absolute measurements. I've used a phone app to give me a rough idea of what sort of reduction in noise I got when I fired a round in my garage vs what it sounded like at the street or inside my house. Even if the sample rate was up there, the cheap units and phone apps don't have the range for the dB level of a gunshot. I've wondered if maybe this could be gotten around somewhat by enclosing the meter in a sound-attenuating enclosure. Let's say that you have a meter that will do 130 dB, but you are wanting to measure gunshots which are probably 150 dB. If you can put the meter in a sound-attenuating enclosure that was good for 30 dB, that would bring it down into the range where that meter could handle it. Of course, you still have the problem of sound impulse / duration.

[Czech_too]

I appreciate all of the suggestions, comments, links & pictures.
May just be spinning my wheels here, but I feel like I have to at least make some effort to get along with the land owners, otherwise....
Wish that others on the board would feel the same, but that would be another topic altogether.

[popper]

Concrete pipe or those old clay sewer pipes is probably the cheapest for a 'test'. 50 Db is loud, 70 is pain threshold, 120 is hazard. Muffs usually are spec'd for an attenuation. The recording device needs dynamic range greater than the expected measurement, 80 Db is typical. Record ambient - lightly tap a table with hammer or something, then muffs on the mike and test. Db is easy to figure - use ambient noise as zero (unity) then it's a log scale from there. Absolute 0 Db is VERY expensive - anechoic chamber and all - nothing you really need.

[Ickisrulz]

I appreciate all of the suggestions, comments, links & pictures.
May just be spinning my wheels here, but I feel like I have to at least make some effort to get along with the land owners, otherwise....
Wish that others on the board would feel the same, but that would be another topic altogether.

If an organization is serious, a consultation with professional noise attenuation company is the best route to a guaranteed successful solution. It won't be inexpensive though.

[Kraschenbirn]

Been down this road a couple times in the past. As previously stated, most hand-held meters...even the expensive ones...are intended for indoor use, like measuring industrial noise levels for OSHA compliance, but are pretty much useless outdoors. NRA publishes are fairly comprehensive guide for a reasonable price that covers just about every facet of range planning/construction/operations.

http://materials.nrahq.org/2012-nra-range-source-book.html

Bill

[popper]

http://soundbible.com/1638-M1-Garand-Gun.html
M1 Garand shots.
per Sony SoundForge, 90Db peak, unknown distance. Koenig, LLC recorded.

[Ickisrulz]

Been down this road a couple times in the past. As previously stated, most hand-held meters...even the expensive ones...are intended for indoor use, like measuring industrial noise levels for OSHA compliance, but are pretty much useless outdoors. NRA publishes are fairly comprehensive guide for a reasonable price that covers just about every facet of range planning/construction/operations.

http://materials.nrahq.org/2012-nra-range-source-book.html

Bill

I performed an awful lot of noise surveys during my time in the USAF. This included static noise readings, octave band analysis and dosimetry and never ran across any meter intended for indoor use only. When obtaining readings outside a wind screen is used. This is just a foam cover for the microphone.

[Eddie17]

Great info, pictures Artful! Thanks have to show to my local club.

[Artful]

http://soundbible.com/1638-M1-Garand-Gun.html
M1 Garand shots.
per Sony SoundForge, 90Db peak, unknown distance. Koenig, LLC recorded.

No Garand firing a service load at any reasonable distance of measure will register at 90 db!

Boeing 737 or DC-9 aircraft at one nautical mile (6080 ft) before landing (97 dB);
power mower (96 dB); motorcycle with good muffler at 25 ft (90 dB).
Newspaper press (97 dB).

90dB is 4 times as loud as 70 dB. Likely damage in 8 hour exposure

[Artful]

Great info, pictures Artful! Thanks have to show to my local club.

Your welcome - show us what your club does after they change your range!

[popper]

Artful my comment is only that a noise reduction testing is relatively easy with inexpensive equipment. DbA is different from dB. IMHO the OP needs a test to compare noise reduction, not certification, to start. If the OP needs a city cert. range cost is ~$1.5M.

[Bookworm]

90dB is 4 times as loud as 70 dB. Likely damage in 8 hour exposure

Actually, I believe you are incorrect. The dB scale is not linear.
70 is 10x louder than 60.
80 is 10x louder than 70.
90 dB is 10x louder than 80.

so 90dB is actually almost 100x louder than 70 (10x10, or 10 squared)

That's how a conversation can scale at 60, and a mower at 96
The volume doubles approximately every 3dB

[Ickisrulz]

Actually, I believe you are incorrect. The dB scale is not linear.
70 is 10x louder than 60.
80 is 10x louder than 70.
90 dB is 10x louder than 80.

so 90dB is actually almost 100x louder than 70 (10x10, or 10 squared)

That's how a conversation can scale at 60, and a mower at 96
The volume doubles approximately every 3dB

I think Artful's conclusion was based on the OSHA permissible exposure for noise. For each increase of 5 dB the length one may be exposed is cut in half.

You can be exposed to an average of 90 dB(A) for 8 hours/day. If your exposure is an average of 95 dB(A) the time reduces to 4 hours/day. If your exposure is 100 dB(A) then it is 2 hours/day and so on.

[popper]

DB = 10*log(noise sample/reference sample). DBA is weighted to the human ear but there are several weighting curves. 357mag is supposed to be 136dBA, howitzer is 165dBA. I used to walk under the 5"38 when firing, noisy but not unbearable. If gunshot noise is so bad for us the guys in firefights in WWII would be deaf. The ones I have met weren't. But yes, we need ear protection - come on Washington, let us have suppressors.

[Ickisrulz]

DB = 10*log(noise sample/reference sample). DBA is weighted to the human ear but there are several weighting curves. 357mag is supposed to be 136dBA, howitzer is 165dBA. I used to walk under the 5"38 when firing, noisy but not unbearable. If gunshot noise is so bad for us the guys in firefights in WWII would be deaf. The ones I have met weren't. But yes, we need ear protection - come on Washington, let us have suppressors.

When impact/impulse noise is measure and considered, no weighting is used. An M9 pistol has a sound level of 157 dB at the shooter's ear. The 357 mag will be louder for sure.