Suppressor Testing w/ Sound Measuring Equipment.

[35Remington]

The following link will be a good read for all of you: http://www.qsmsilencers.com/Dr. Matt Branch AAOHNS Article.pdf

ALso, FWIW, SilencerShop seems to do many of their tests at public ranges near Austin, and one can certainly hear other guns going off in the background. While I agree private land is ideal, don't scrap this plan just based on venue availability.

I am very interested in your results. Would also like you to measure the volume of other relative sounds out there, like bolt closing, safety flipping, talking, stepping on a stick, etc. If this were closer to SA I would bring a bunch of toys and my chrono as well.

 

[AaronP220]

We checked out the sound meter the other night. The meter is good to go. Picked up everything we were doing as far as noises. Clapping. Slamming boards. Talking. Snapping. The manual says the sample rates etc will handle gun shots just fine. We've worked out how we want to set the test up as far as removing testing variables and things like that. So we're moving forward at least.

 

[1slow01Z71]

Theres only a handful of meters actually capable of accurately recording a gunshot. Unless it cost you 5K+ it does not have the response rated needed to capture the peak of the sound wave. The standard testing is one meter 90* from the muzzle. I think itd be a lot of fun to get a actual meter capable of registering a gun shot and test all our goodies. Ive got dozen or so cans that couple be tested. Primarily Id like to know how my Bowers Vers50 does as there is NO meter data out there about it all and its got a rough job on my 10" 458.

Edit: Also you don't need a perfectly quiet range to test. The meter measures the peak sound level which is going to be the gun shot as long as someone isn't shooting unsuppressed a couple feet away. Db scale is logarithmic and falls off very quick.

 

[AaronP220]

It costs over $10,000.

 

[TX69]

The 1st is the gun club in Madisonville

Find lout what they want to rent it for the day and split up the costs?

 

[Mexican_Hippie]

Ideally you'd do the "standard" at 90 degrees and then also get data:
- by the shooters head
- 25 yds out in front of the muzzle
- 50 yds
-75 yds
....

lol - I like data. It's understandable that they don't do this due to expense. I did see a YouTube where they did the recording near the impact. That way you could experience what the animal would hear if you're a hunter.

 

[Glockster69]

We checked out the sound meter the other night. The meter is good to go.

Cool beans.

The 1st is the gun club in Madisonville

Find out what they want to rent it for the day and split up the costs?

There's almost no chance we or any other group would be given exclusive use for a day. That only happens for large competitions. And according to several posts, background noise won't effect getting good data.

 

[Glockster69]

A few thoughts from a 20-year audio engineer (retired)...

- Stay away from concrete pads, under roofs of any type, or near any walls/burms as all will cause reflections and skew the results. Grass will be better than hard packed dirt.

Looking at it with Google Earth and a few pictures he's shown me, the Fairfield property is all dirt.

Alan, how far from concrete and roofs is sufficient?

 

[Vaquero]

Funny.
It's just so hard for some people to believe that other people might know what they're doing.

Aaron, Chuck.
Good deal and keep us informed.
Thanks.

Curtis. Not you.

 

[acorneau]

Looking at it with Google Earth and a few pictures he's shown me, the Fairfield property is all dirt.

Alan, how far from concrete and roofs is sufficient?

Imagine the concrete floor and/or roof as a big flat mirror. If there is a chance of getting a reflection between the gun being tested and the microphone move out a bit.

 

[benenglish]

Yeah. I'm not sure if he did it or someone else did but as soon as he set it up I believe someone blasted one of the posts.

It was someone else. I don't blame them. It was my chrono; I should have insisted on doing the shooting.

 

[benenglish]

Most test to their own standard. SilencerCo for example does not even user MILSTD equipment.

I love standards...especially since I have lots of experience making them up out of thin air and forcing other people to abide by them. As usual, XKCD has something on-topic:

 

[benenglish]

We checked out the sound meter the other night. The meter is good to go.

I kinda wish I wasn't so late to this thread. One test I know is difficult (a very fast transient) is the sound of a tight pair of quality scissors cutting. As simple as it sounds, that "snip" sound is such a quick peak that it's a sort of informal standard for certain sound reproduction equipment measurements.

 

[benenglish]

Ideally you'd do the "standard" at 90 degrees and then also get data:
- by the shooters head
- 25 yds out in front of the muzzle
- 50 yds
-75 yds
....

lol - I like data. It's understandable that they don't do this due to expense. I did see a YouTube where they did the recording near the impact. That way you could experience what the animal would hear if you're a hunter.

That sure adds a lot of data points.

Once a certain methodology is settled on, however, what's to prevent taking all those measurements for just a couple of set-ups? If the relative changes in SPL stay the same, that could still be a useful guide.

 

[benenglish]

OT Warning

It's weird but I had this conversation with a suppressor mfg over 30 years ago that leaps to mind. What powder?

Some powders have flash suppressants and some don't. Some are notably louder than others. Pushing the same bullets at the same velocities, for example, H4895 will be quieter than H335 which will be quieter than SR4759. (Since I'm coming from the rifle-caliber pistol world, there are actual use cases where those three powders might be valid choices in the same cartridge, behind the same bullet.)

I've always wondered if there were some powders that worked better with suppressors than others.

Obviously, for this test the answer is to simply use the same ammo for everything and eliminate this variable. However, one of these days I'd love to see if someone could figure out if it's possible to make ammo quieter from suppressed firearms by judiciously selecting the powder used.

 

[Mexican_Hippie]

I'm imaging the data from all over and visualized like the stop film technique in the Matrix.

You could use a 1-2db gray or color scale gradient to visualize the sound in 3d from different angles and distances. Of course you'd need software to fill in the gaps.

Sorry to derail, just thinking how you would model the data in an ideal world with limitless budget.

 

[Sugar Land]

I am sure the data points are endless. and could take days to record. Thanks for the input.

 

[AaronP220]

Chuck and I have worked out something that we think is the best way to go. Simple measuring Deltas. Suppressed / Unsuppressed with different guns and ammo. Even that "simple" objective is likely a FULL days work of data collecting.

 

[CZPistol]

H4895 will be quieter than H335 ....However, one of these days I'd love to see if someone could figure out if it's possible to make ammo quieter from suppressed firearms by judiciously selecting the powder used.

Forgive my ingorance, but then does it not stand to reason that, all other cartridge components being equal, since H4895 starts out quieter than H335, H4895 would also be quieter than H335 when fired through a suppressor?

 

[ZX9RCAM]

I presume that for the sake of ease & consistency, only one type of ammo will be used for the testing?