Youtube, bloggers  everyone's a friggin expert these days.

This thread definitely shows the lack of quality suppressor meter testing videos. Most suppressor "reviews" are just a guy saying, "it's pretty quiet" and testing with a junk meter, if at all.

I didn't know much about the .mil standards and how different meters stack up before this thread, so thanks to the guys posting good info.

Agreed if you are posting data and want to be credible at least use the proper tools especially if you are posting in a tech forum.

In this thread random joes try to teach industry experts about their own industries...  wtf is wrong with people.

Shit meets spec or it doesn’t.

That piece was done by PHD, if the meter is that inaccurate why would PHD have done the article on it?

I would like to get together with someone with their 2209 and compare with same weighting system side by side.

*cracks another beer*
There was a post in GD years ago - something to the effect of...
"Arfcom: some of the brightest minds in America arguing with some of the dumbest mother fuckers on the internet"

I hate sound testing.  It's got to be one of the most difficult things to measure for a myriad of reasons:

-It's transient (the thing you measured, can never be re-measured--like a machined piece of metal).
-It's very affected by environment.
-It's a process.  The meter is only part of it--you have to assess muzzle placement alignment with mic, environmental stuff, wind, host weapon, the operator's interaction, it goes on and on...

I'm super anal about all of it, so it's always a stressful day.  We use a National Instrument setup like Silencerco's.  I have very good faith in it.  I believe the faster sampling rate required in the new MIL-STD-1474E is needed more for the super high pressures above 170 dB.  I've done testing with Silencer Shop and I think their 2270 is actually OK.  But first, here's some Cliff notes on assessing sound systems:

These are the parameters that you look at when doing a measurement system analysis.  Remember--it's not just the meter, it's a SYSTEM.  That includes operator interaction, setup, environment, etc....

1.  Bias--this is how closely it matches a known standard.  With sound meters you calibrate at a certain sound level.  Mine is at 114 dB.  This is also called accuracy.

2.  Repeatability and reproducibility-- This is how consistent it is.  This is super hard to assess because the sound is a transient impulse.  We do "pseudoreplicates" of large shot strings to simulate the measurable item over and over to gain confidence in the output.  Reproducibility is being able to have someone else do the same thing or you yourself do it again the next day (think system, not just meter) with very little variation.  Repeatability is also called precision.  Yes, precision is different than accuracy.

3.  Linearity-- This is the ability of the system to measure equally and proportionally across it's range.  Picture a ruler that's six feet long.  If each mark is only a few thou' off on a 12" ruler, you wouldn't notice.  By the time you hit six feet, you'd have a significant difference.

4.  Stability--This kind of looks at all of the parameters above in a time sense.  Stability is a real issue in sound testing.  I test the same can multiple times through a test session if it goes long.

I believe the Larson Davis meter has issues with all of the above.  Bias is an issue when reading 123 dB on average when it should be around 133 dB.  It's like hitting the guys target next to you on the range.  Repeatability is having one shot measure in the mid-130's the next measure in the mid-120's.  That's like having your target shot grouping open up to 10 MOA.

Getting back to Silencer Shop's B&K 2270, I believe it has just a little bit of bias because of the lack of sampling rate.  It has almost always metered 1-2 dB lower than our NI system when shot back-to-back.  You can get good consistency with it the better you orient the mic, control EXACTLY where the muzzle sits, and reduce environmental objects.  One source of error that I'll discuss here was back when they were just loosely standing next to it while shooting.  Tyler fixed a lot of that when he started working there.

In the end, I see my NI system as a micrometer that will measure tenths of thousandths of an inch.  It does well in a lab and it's very accurate and precise.  I can use it assess products during development.  If I see a 1 dB difference between products, I know that could just be noise and not act on it.  If I see a 2 dB difference I know I can trust it.  Several 1-2 dB modifications to a suppressor can really add up.  A B&K 2270 is like a set of calipers that measures in the thousandths.  You loose a little bit of the accuracy and precision, but it's still very reliable.  I may not trust my results if I see a 2 dB difference unless I had several shot groups.  The LD LXT-1 is like a ruler.  That wooden kind.  With the flaky paint.  I couldn't use that at all in my product development.

Sorry.  That was boring--but this is real engineering and real work.

Todd Magee
Dead Air Engineering

Nice write up Todd. Just curious if you've played around with spectrograms as a way of characterizing suppressor performance vs just a single dB value? I know NI has some spectrogram VIs but it's been a LONG time since I've used LabView to do any kind of data acquisition and signal processing.

Thanks for that, Todd--some of us really appreciate it when the pros take time to give us a little insight into the details!

I didn't know MAC's meter doesn't meet the spec.  What's the consensus on the validity of his numbers?  Same as Silencer Shop?

Excellent post, Todd. Thanks for that. It was great meeting you at SHOT as well.

I like the micrometer - caliper - ruler example.

@mikesmith13807 I would say that yes, MAC's numbers could be compared to Silencer Shop's - at least for the most part. He uses the same meter, but environmental factors will differ somewhat. He appears to do a good job of keeping mic placement consistent, so I trust his process.

Also as Todd mentioned, Silencer Shop has done a lot over the last few years to increase the consistency of their testing.

The MIL-STD 1474E has dropped the next to muzzle reference positions, only indicating the ear measurements.

It has also increased the distance to reflective surfaces to 30 m   ( less works very well in practice though )

Sampling rate required is up to 192,000 from 160,000

With regards to the manufacturer/equipment list, to my knowledge SureFire also uses the B&K PULSE system.

Best Regards!

Tuukka Jokinen
Ase Utra sound suppressors

Some amazing replies in this thread.  I've  always wondered about the calibration standard for a very high magnitude impulse noise. I think the practical takeaway here for amateur product reviewers and video documentation is to always have a 'reference' can and ammo setup with the hosts and conditions as similar as possible.  I think this was the consensus on the Claymore thread.

Todd's point about data as an engineering development tool needs to be contrasted against data being used (Mis-used?) as a comparative marketing tool.  Particularly since many of us use the products (happily) on sub-bore calibers and barrel lengths different than what the stated average is tested on, I'd imagine the user variability and standard deviation swamps even the variables that plague controlled testing.  Then there is user environment and individual ears.  There are some cans out there that sound really good relative to their stated meter levels.

I appreciate the OP's efforts and hope the comments here act as a fine polish.  I particularly like seeing the unicorn RDB as a host.  Seems like the lack of blowback gas is pretty sweet, and subjective comments about port pop are useful.

Thanks to all from industry that have replied with the technical aspects of sound metering.

OP - Consider changing the topic title to "The Amazing AAC SR5 - Industry Experts Analyze Sound Metering". For better or worse, very few posts have ever gained this much interest from big names in the suppressor world.

That's really all they should be.  It's not cost justified to replicate .mil testing and that number doesn't even give people the info they really need.  Many people would be happy with a can that meters higher and has less blowback and sounds quieter at the ear (I've personally had people who never shot with a can before shoot the MaxFlo side by side with this can and 100% of them liked the Maxflow better) because of the shooting experience.

99.9999999% of people who purchase a can don't purchase a sound meter to go along with it.  And even if they did they wouldn't bring their meter to the range shoot the gun and then read the number and decide if they felt good.  They shoot with the can, hear it, and go hmm that sounds good or meh that sounds kinda loud.

Having some comparison numbers to go along with the test is nice, that's why I borrowed the meter for some videos.  If a potential buyer wants to know the absolute sound level they're probably just gonna read what's on the manufacturers website and go with that.

RTIC vs Yeti thread. 

I will just stick with my Gem-tech Halo, as I have no purse to swing.

I think you can go to a particular place on the site and learn how to post pictures.

----

Silencer industry drama vs. YouTube hillbilly "testing". This thread is firing on all cylinders.

What does a proper sound meter cost?

I'll answer your comments in order:

The "seems to be going really fast" comparison is bullshit, because literally listening to the can is exactly what people do and what will make them happy.  Watching a bullet is not the same.

It's not worth it to test 100 cans on a YouTube channel either.  They don't even make those analog meters anymore, anything that meets the standard is really expensive and just doesn't make sense for a YouTuber.  If I owned a company doing R&D on cans sure, but not for reviews.

Metering at the ear hasn't been adopted as an industry standard, so the comparison of numbers becomes more difficult.

Just like with a chrono you can read the box and know what type of velocity to expect, a chronograph is also very cost effective most people should own one.

Because people like them.  I'm making review videos not doing lab research.  Often times I post links to videos on arfcom and people bitch and bitch and bitch, but the feedback from YouTube is very positive.  Because not everyone is a hardcore silencer nerd and many people just like some data that shows it's doing what its supposed to.

Manufacturers should be testing to a standard to produce comparable numbers, anything else is a waste of time.

I've been told $50,000 ish for the digital ones that meet the standard.  Or you can try to find an analog one that isn't made anymore.

I think the future is going to be using high quality microphones and data acquisition system to just plot the entire wave and a spreadsheet to convert to dB.

Interesting that for whatever reason the LD measured the unsuppressed shot so low. When I used the meter, I obtained an average over 5 shots from a 22" rifle of 163.3 dB..

If the analog gauge is the gold standard, why isn't it made anymore, or why hasn't someone come along and built a meter to take it's place?

The exact same meter, Buffman shipped it to me.

1. It IS subjective, which is all the more reason one person saying "it's loud" or "it's quiet" doesn't count for much. People with multiple cans will have different opinions about which one sounds the best to them, so how does that make for valuable review information? You could end up with a completely different opinion than the reviewer. There's no way to know exactly how you'll like a particular can without trying it yourself, but there IS a way to get reasonable accurate NUMBERS about a can's performance. That's far more useful for comparing one can to another than any one other person's opinion.

2. HansohnBrothers corrected you by pointing out that there is a standard, so there you go.

3. If people who actually know that they're talking about pointing out the flaws in your testing is "bitching" to you then I don't know what to say.

It's almost as if you have to value the opinion of the person giving the review lol.   Why would you ever make a video if all you were going to do is show numbers from a meter?  You could just write a few sentences and be done with it.   If the entirety of your video can be summed up in two sentences it doesn't need to be a video.  The reason people watch online reviews is to hear the opinion of the reviewer.

There is a standard that everyone follows?  I thought I just read someone say even all manufacturers numbers aren't even comparable.  Which is it?

That's a long post for someone who doesn't know what to say lol

EDIT:  Found it, it was you lmao

I do agree it would be nice if there was an industry wide standard that everyone used.

Yeah, but not always.  That 1-2 dB falls under bias (from my post above) and it's not like it's a constant.  Test setup (remember, this is a process) can negate it or enhance it.  If the mic is a tad closer than 1 meter or it's maybe 1 cm in front of the front cap of the suppressor then you may find it averages the same.   Backing the mic off the front of the can by a few cm can really help consistency.  Or, if you put it all the way back at the muzzle of the gun, it helps your marketing (see Silencerco).  Anyone notice a few years back how all of their numbers dropped by a few dB?  That's why.

Which is another thing.  People love to hang their hat on averages without looking at the spread.  If you're target shooting and you have one load that hits 1" on average from the another load, but both are 5 MOA, you would never been able to tell the two groups apart.  Only a few hits on either side would truly be "different".  That's suppressor averages for you.  The bell curves can overlap 90%, but the one that is 2 dB quieter on average is declared a winner by dB weenies.

The trick is to reduce all variation in testing.  The more you keep things exactly the same when testing, the more accuracy and precision you'll have.

Good point.  I learned this saying from my stats teacher:  "Engineers (or silencer companies, youtube personalities, fanbois, whatever) use statistics like a drunk uses a lamp post--more for support than illumination".  Most people stumble through sound testing and in the end they're just filming their learning process.  I don't fault the OP for this.  My reference to Silencerco above is a perfect example, though.

Thanks.  Yep, I've definitely used frequency response curves, but not actual spectrograms.  I think those are more for continuous sound, but I guess I need to look into those more.  I feel like it's more of an art than a real science for me when applying it to product development.  Like, I'm not taking a dozen representative curves from two test variables and overlaying them and doing scary calculus.

I'll try to keep it simple so you can keep up.

There is a military standard for testing (MIL-STD 1474E). This includes at ear measurement. Not all manufacturer's use that standard. They use meters that don't meet the requirements, or different measurement parameters. I'm not even sure they all make their testing methods public. So when I say it would be nice to have an industry standard, I mean it would be nice if suppressor companies agreed to all use the same standard consistently, to make comparisons easier. Using MIL-STD 1474E would make the most sense, but it could be different. The idea is to have them all doing it the same way, which they don't right now. Keeping up so far? If not go back and read the thread, it's all been covered.

You do have to value the opinion of the reviewer, and having watched your other videos, my value of your opinion on suppressors is exactly zero. I do like to have some quality feedback and impressions from the reviewer ALONG with the numbers, but I ALSO would like the numbers. Who said anything about video with ONLY numbers and nothing else?

When I said "I don't know what to say" I meant in regards to your comment about everyone "bitching" (I have plenty to say about your mediocre review). I would say maybe learn to admit when you're wrong and try learning a thing or two from the more knowledgeable folks, but clearly you refuse to look at criticism as anything other than "bitching" so I won't waste any more of my time.

That's good you won't waste any more of your time being wrong and bitching.

Yep, exact same meter. Just for clarification, I do not do reviews for AR15.com (yet) :)

You are being incredibly defensive when you could just take the opportunity to listen and learn from industry professionals.

The “industry professionals” in this situation are only worried about others testing their cans and giving numbers.

Since the LD LXT1 is the meter that a few have gotten and used some now want to say the bk 2270 is not to bad because silencer shop and Mac use it. This is crazy, the Larson Davis lxt1 is and has the closest specs to the mil spec standard in a digital meter and is the best option today. There are some professionals that worked on changing some standards and the Larson Davis would be the best option as a meter to use if that ever happens.

I’m in Illinois if we can get together somewhere to test side by side.

This thread =

Attached File

No kidding. These threads just turn into pissing matches. Despite the drama I really appreciate the likes of AAC, DA, TBA, PHD etc and our industry partners chiming in to try and clean the process up.

No crazy is trying to justify the use of a meter that does not work but is close. The best option is to use a meter that works properly. Folks using a meter that does not work and then reporting the results (like 123 on 556) do more harm than good and set the industry back 20 years.

And the worst part is folks using this meter have never done a side by side or s gunshot calibration to know how bad it is.

Imagine if cops used a radar gun that was off up to 10 mph.

How long do we have to wait until we stop hearing people refer to "industry standard" and just talk about milspec xxxx?  Have you ever heard anybody refer to the AR-15 "industry standard"?  Of course not, because we have milspec to keep everybody on the same page!

As a community of users, prospective customers, reviewers, experts, etc. we need to unite and force manufacturers to get with the program and stop enabling the manipulation and suppression of data for marketing purposes.  There's no reason we shouldn't have reliable data available at this point to compare every product's performance at the ear (and the muzzle, of course).

The reason good data isn't universal is it is expensive and painstaking to get.  Then reducing that data to one figure of merit takes all that resolution and smears it with a broad brush.  In the end it's the VHS vs Beta conundrum and good marketing and customer support usually trumps the engineers micrometer evaluations.  And by good marketing I don't mean SilencerCo lifestyle vids, I mean getting the right information out in a useful form.

Getting back to the awesome video theme of this discussion, many posts in this sub forum come down to people trying to select between a couple of similar candidates. So since we've already mentioned the utility of having a reference suppressor for a meter bench mark, I'd also suggest that judicious pairing might also help inform that final choice between top contenders.  Videos comments as to mounting, cleaning, options can also be useful.

I'd like to hear and contrast the Halcyon against the Oculus and maybe the Optimus Micro for rimfire and 5.7.  It might be a while before those are all out in the wild but I think that would be a popular video.

Similarly I'd like to see the Sandman K versus Omega 9k on short 8-10" barrel 300BO with supers and subsonics.

Finally Obsidian 9 vs Tirant 9m.  With typical 147gn subsonic in both configurations and commentary on blowback on a pistol.

Did I mention steel targets should be banned from suppressor vids?  Just trying to be helpful...

^ The Halcyon ran good on my 5.7 hosts (FSN and SBR). Even ran pretty good on the PMR-30

Which of these industry professionals make YouTube videos?