User Panel
Posted: 2/8/2016 8:42:00 PM EDT
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[#1]
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https://youtu.be/2vPfOMCZusA Silencer Shop released their sound meter test data for of the Griffin Armament Optimus sound suppressor. We appreciate their work in putting it into some configs to give people a little insight into how it works in some of the applications and configs possible. View Quote Mother of pearl, it even got good numbers. Hopefully someone gets these in stock soon! |
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[#2]
I want Tyler's job. He gets to have fun and work!
Nice video, looks good for those who want a do all. |
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[#3]
Noice. It's going to suck having to wait 6 months for my optimus to get out of jail.
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[#4]
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Mother of pearl, it even got good numbers. Hopefully someone gets these in stock soon! View Quote View All Quotes View All Quotes Quoted:
Quoted:
https://youtu.be/2vPfOMCZusA Silencer Shop released their sound meter test data for of the Griffin Armament Optimus sound suppressor. We appreciate their work in putting it into some configs to give people a little insight into how it works in some of the applications and configs possible. Mother of pearl, it even got good numbers. Hopefully someone gets these in stock soon! I've hinted at the numbers here a few times the past couple weeks. If I hadn't tried the can before they were shared with me, I would have had a tough time believing them. If you're willing to accept a little extra length over a caliber specific can, the Optimus will work very well. Seeing is definitely believing, but Silencer Shop's test is no fluke. |
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[#6]
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I've hinted at the numbers here a couple of times the past couple weeks. If I hadn't tried the can before they were shared with me, I would have had a tough time believing them. If you're willing to accept a little extra length over a caliber specific can, the Optimus will work very well. Seeing is definitely believing, but Silencer Shop's test is no fluke. View Quote View All Quotes View All Quotes Quoted:
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https://youtu.be/2vPfOMCZusA Silencer Shop released their sound meter test data for of the Griffin Armament Optimus sound suppressor. We appreciate their work in putting it into some configs to give people a little insight into how it works in some of the applications and configs possible. Mother of pearl, it even got good numbers. Hopefully someone gets these in stock soon! I've hinted at the numbers here a couple of times the past couple weeks. If I hadn't tried the can before they were shared with me, I would have had a tough time believing them. If you're willing to accept a little extra length over a caliber specific can, the Optimus will work very well. Seeing is definitely believing, but Silencer Shop's test is no fluke. It was really a nice performing can across calibers. During development we were impressed by that. |
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[#8]
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It was really a nice performing can across calibers. During development we were impressed by that. View Quote View All Quotes View All Quotes Quoted:
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https://youtu.be/2vPfOMCZusA Silencer Shop released their sound meter test data for of the Griffin Armament Optimus sound suppressor. We appreciate their work in putting it into some configs to give people a little insight into how it works in some of the applications and configs possible. Mother of pearl, it even got good numbers. Hopefully someone gets these in stock soon! I've hinted at the numbers here a couple of times the past couple weeks. If I hadn't tried the can before they were shared with me, I would have had a tough time believing them. If you're willing to accept a little extra length over a caliber specific can, the Optimus will work very well. Seeing is definitely believing, but Silencer Shop's test is no fluke. It was really a nice performing can across calibers. During development we were impressed by that. What meter do you guys use to test silencers at the factory? |
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[#9]
We use a B&K2209 like you. The meter is old but it works really well and it is probably still the best meter to use for suppressor R&D. There are only 2 meters that are mil-std compliant as far as I know the B&K2209 being one- both being decades old. A lot of the companies are using systems that are not mil-std compliant, there is a Larson Davis meter for example we've been tempted to buy simply because it looks more modern- Sig is using one of those for example. It is a 30 microsecond peak rise detecting meter, so it is a little slower than the ancient looking 2209. Funny how you either look like you use ancient equipment or you get slightly less accurate data- you have to trade one problem for one solution because firearms suppressors are not a significant market segment for sound testing equipment sales, and sound level meters are not built for our industry but rather are sourced from the industrial safety marketplace for use in our industry.
The really important criteria for an R&D meter is that it be portable and rapidly set up on site. The Larson Davis meter (the old Mil-std and the new non mil-std models) do that, as does the B&K2209. The Pulse system is capable of mil-std metering as far as I know, but sound testing people complain about what a terrible pain in the ass it is to set up- talking about dragging a car battery around and essentially setting up an indoor lab outside. |
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[#10]
what effect would moving the meter to the end of the silencer have on the numbers?
seems like having it at the muzzle and then again where the muzzle/silencer meet would make the naked numbers highest and suppressed lowest. Is there a standard all tests are done to? I don't think there is but was wondering. I'm not trying to crap on the numbers at all, but was wondering if theres a testing standard all the companies use. |
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[#11]
All the more reason I'm buying one after 41f goes into affect
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[#12]
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what effect would moving the meter to the end of the silencer have on the numbers? seems like having it at the muzzle and then again where the muzzle/silencer meet would make the naked numbers highest and suppressed lowest. Is there a standard all tests are done to? I don't think there is but was wondering. I'm not trying to crap on the numbers at all, but was wondering if theres a testing standard all the companies use. View Quote I haven't tested to see what the effect of using mil-std vs the Silencer Co / ASA proposed method is. Mil-std is how we have tested and how we do R&D and testing- that samples 1M left of the muzzle of the unsuppressed barrel, and 1M left of the muzzle of the suppressor. Silencer Co working with the ASA introduced the muzzle of the rifle both suppressed and unsuppressed method and Silencer Shop adopted it on their request as far as I know. So all Silencer Shop testing as far as I know is done that way and has been since the Omega was tested in ~february 2015. For example the second to last 762 can tested- the Rugged Razor hovered around 144DB in Silencer Shop testing, that is using the same testing Silencer Co / ASA standard they used here to test the Optimus. What my point is- is that there are several datapoints for comparison using the new testing method Silencer Shop is using- so when you mention that method, it wasn't integrated for the Optimus and we had nothing to do with that being used. Whenever people talk about standards there are as many opinions as minds weighing on the subject, and we use Mil-std simply because it is what Gemtech, AAC, Surefire, KAC, and other industry companies use and have used for decades, but I feel what is most important is that performance comparisons are conducted using the same testing standard. So silencer shop data compared to other silencer shop data is as scientific as anything else as far as we are concerned. By the same token our testing for product performance ratings should be very comparable to Gemtech or AAC testing, as long as that was done to mil-std which most of it is. When I say most the major exception is disclaimed testing using the shooters ear location which most companies do on occasion- an example being .338LM or 50BMG testing- applications where the major concern is that the shooters ear location be ear safe. |
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[#14]
thanks for the testing info. ive never been much of a dB chaser, but its good to see there is some consistency in testing. good video and looking for one of the sportsmen. just ordered one
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[#15]
thanks for the info. The optimus is definitely on my list of cans to buy
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[#17]
The comparison test of the Mil-STD to ASA methods was interesting. Thanks for the post Tuuka.
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[#18]
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[#19]
The argument that some manufacturers use is that the muzzle of the gun doesn't change when you add a silencer. Therefore the location of the meter doesn't change. Not saying it's right or wrong but if everything is tested at the same location then you can compare apples to apples.
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[#20]
Silencer Shop explained their process/logic on their blog last year...here's the link.
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[#21]
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The argument that some manufacturers use is that the muzzle of the gun doesn't change when you add a silencer. Therefore the location of the meter doesn't change. Not saying it's right or wrong but if everything is tested at the same location then you can compare apples to apples. View Quote That just doesn't make good sense. If you want apples to apples, you need to be testing from a repeatable distance....FROM THE SOURCE OF THE WAVE. While it might fool some to test from "the same location", every time......it doesn't take a lot of high level thinking to see this is bogus. IMHO. |
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[#22]
I agree with you. However if some manufacturers are testing at the end of the silencer and others are not then it is not a fair comparison. So we chose to test everyone at the same location so that you can tell how they compare to each other.
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[#23]
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I agree with you. However if some manufacturers are testing at the end of the silencer and others are not then it is not a fair comparison. So we chose to test everyone at the same location so that you can tell how they compare to each other. View Quote I'm confused. Do you mean so that we can see how they compare based on the numbers the manufacturers are putting out themselves? |
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[#24]
No what I am saying is that if there is a universal test that is done the same way each time then you can accurately compare the dB ratings of each silencer. So by us testing at the muzzle then you can compare silencers tested by this method.
We will be doing a test soon to show what the difference is between testing at the muzzle vs testing at the end of the silencer. Mostly to show what the difference would be in dB ratings. |
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[#25]
Philosophically if Silencer Shop uses Mil-Std then customers could unfavorably compare a product to a Silencer Co product which that product performance matches. Obviously with two standards there are pro's and cons to using either so to some people either method will be wrong. Really it would be more simple if companies in the industry didn't try to re-invent the wheel. But they did.
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[#28]
I think it is probably important to understand the way mil-std ~10-20microsecond rise time, compares to ~30microsecond rise metering (something we might take a look at in the future by conducting some testing to help people understand the likely influence of differential rise time between these two types of systems).
However; I don't think dropping to minimum theoretical rise time would do anything more than add another standard, further increasing the in-comparability of results on the market which would then vary by a factor of 9 from ~3-~30micro seconds where currently the comparability is only influenced by a factor of 2 from ~15-~30. I believe the fastest available systems (which are not portable) have ~3-4 microsecond peak system rise time limitations and all that faster equipment is not really portable or affordable for industry companies, so that data is important to consider. So in my opinion as someone who has followed sound testing from the late 90's to present time, portable meters with mil-std, or with ~30microsecond peak rise time should be used for suppressor testing. This limits testing to 2 older meters, and as far as I know 2 modern portable meters- both from Larson Davis and Bruel & Kjaer respectively. Whenever testing is conducted, the meter used should be specified, so that people know which peak rise time approximately they are looking at. Hearing risk is rated based on time and SPL, so metering the absolute crests of peaks at nearly zero duration in time is probably not going to yield an accurate assessment of overall hearing risk. I see the obvious reasons to meter very near to peak amplitude, but at the same time I also see reasons not to meter unrealistically short representations of peak sound for the purpose of a hearing damage risk assessment- that one number value used to represent a waveform of varying amplitude and duration. For example, if we meter [completely hypothetically] 4DB louder at 1/3 or 1/4 the time of mil-std, does that mean that the SPL occurring in 1/4 of the already very short duration in time is more significant? I would say no. Mil-std to ~30microsecond peak rise would be ~ twice the duration of sound- a little less substantial to the effect that my engineering hypothesis would be that ~20microseconds (where the military scientists wanted to be) is probably ideal for conducting this type of testing. B&K 2209's sample at ~16microseconds and that is very near to that. My experience with cans metered on the 2209 is that cans ear metering at 140 do seem to be borderline dangerous to my ears (an unscientific perception), so I feel the mil-std A weighted results fairly closely parallel the OSHA risk limit for practical purposes. This is supported by the fact that C weighted firearms impulse noise (what the OSHA scale is based on) is fairly close to A weighting of the same, and also by the fact that OSHA impulse noise is considered to be duration of less than 50 microseconds- in other words it was probably built around ~30microsecond equipment (what is more commonly available) running C weighting, so Mil-std A weighted at ~16microseconds is actually probably less lenient than the OSHA std for impulse noise. The people arguing for faster sampling or different weighting are disregarding the fact that a new hearing risk scale would be required to interpret data taken with faster equipment. That doesn't exist of course, so they are in essence arguing for a move to data that has no ability to be interpreted- like a new measuring system combining inch and metric that no one is familiar with. Confusion would be the result of such a move. Anything you find on this topic will be an opinion piece, because even the scientists are talking about analytical data, and then interpreting the results which is where their opinion comes into the argument. What is not opinion but rather fact, is that over 2 decades of data at a ~20 microsecond standard exists, and that very recently, some industry motion to ~30 microsecond systems has occurred. |
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[#29]
This is kind of unrelated, but is it possible to use the Optimus in the mid or full size configuration on a 9MM carbine? Looking to add a very short 9mm ar upper at some point and thought it would be nice if I could get some type of taper mount muzzle device or somehow use the direct thread taper mount adapter to work with a 1/2-36 threaded 9mm barrel to get a little better sound reduction.
Looking to place an order with Silencer Shop within the week. |
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[#32]
I looked at the manual for the B&K 2270 and that suggested the sampling rate of the B&K 2270 used by Silencer Shop is 20.1 microseconds [48KHZ], but the impulse peak is based on a 35 microsecond constant. I couldn't find the data for sampling speed of the 2209 in A weighting but it appears to be equal or faster because the minor discrepancies in data trend toward the 2209 hearing a noise as louder - as far as I know only having sent products to be tested. We haven't tested products on the same day in the same location with both meters so I can't be any more accurate than that.
Again rather than ask for unrealistic specs that most industry grade equipment is not capable of, the 20-30 microsecond arena I would consider ideal. If anything needs to be done, it would be to revisit OSHA's risk level and develop risk limit parameters built for ~25 microseconds rather than 50 where it is. This might for example move the 140DB limit to 143, which would probably soften the arguments that people have made that A weighting and mil-std are inadequate because the shorter duration of measurement would have to raise the risk limit because the 50 microsecond data used to develop the 140DB C weighted limit was probably substantially clipped. |
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[#33]
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[#34]
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Probably few if any. We are selling them. I've used it. It works and adds functionality to the Optimus for end users who have A2 mounts or who own our A2 length or flash comp mounts and want to run a can some of the time. View Quote View All Quotes View All Quotes Quoted:
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Has anyone used the Optimus a2 mount? Probably few if any. We are selling them. I've used it. It works and adds functionality to the Optimus for end users who have A2 mounts or who own our A2 length or flash comp mounts and want to run a can some of the time. I had thought of getting it since I'd say probably 10 of my rifles still have it and majority of my close friends and family have a2's. Was just curious about how tight lock up and the seal was. |
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[#35]
Quoted: I looked at the manual for the B&K 2270 and that suggested the sampling rate of the B&K 2270 used by Silencer Shop is 20.1 microseconds [48KHZ], but the impulse peak is based on a 35 microsecond constant. I couldn't find the data for sampling speed of the 2209 in A weighting but it appears to be equal or faster because the minor discrepancies in data trend toward the 2209 hearing a noise as louder - as far as I know only having sent products to be tested. We haven't tested products on the same day in the same location with both meters so I can't be any more accurate than that. Again rather than ask for unrealistic specs that most industry grade equipment is not capable of, the 20-30 microsecond arena I would consider ideal. If anything needs to be done, it would be to revisit OSHA's risk level and develop risk limit parameters built for ~25 microseconds rather than 50 where it is. This might for example move the 140DB limit to 143, which would probably soften the arguments that people have made that A weighting and mil-std are inadequate because the shorter duration of measurement would have to raise the risk limit because the 50 microsecond data used to develop the 140DB C weighted limit was probably substantially clipped. View Quote The 20.1 microseconds is related to the sampling rate. 48 kHz is 48,000 samples per second. If you take the inverse of the sampling rate (1/Sampling Rate = 1/48,000 = 0.00002083 = 20.83 microseconds per sample. That is different than the rise time spec, which relates to the bandwidth (frequency range) of the input signal that the system can handle. (1) a transducer which converts the physical phenomenon, in this case, sound pressure, into an electrical signal. (2) the signal is then conditioned - where filtering to band limit the signal and amplification occurs. (3) then, in the case of the digital noise meter, the signal is digitized. This is where all those specs like rise time, sampling rate, resolution etc. are important. (4) then the signal is processed - in this case the meter does the conversions/calculations and spits out a decibel rating. What I am talking about relates to step 3. We haven't even discussed converting the signal to dB and what sort of weighting is applied to the measurement. I don't believe I'm asking for an unrealistic equipment specifications. This stuff is all outlined in MIL-STD-1474D, which everybody is claiming they test to. Here's an excerpt of the relevant portion of the spec: Section 5.3.1.1.5 calls out a rise time of not more than 20 microseconds - and 20 microseconds translates to a bandwidth of 17.5 kHz. Section 5.3.1.2.2 calls out a minimum sampling rate of 160 kHz or 160,000 samples per second or 6.25 microseconds per sample (compared to the 20.1 microseconds per sample above when the sample rate is 48 kHz). If people are testing to the MIl-STD-1474D standard, they NEED to use equipment that meets those specifications. This isn't an unreasonable request. MIL-STD-1474E is even more demanding on the sample rate. |
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[#36]
I believe the recording they are talking about collection of the metered numbers which could occur by various means. They are also allowing photographs of the screen of an attached oscilloscope. You can set up a 2209 to do that but most people read the dial and write the numbers down. Historically multiple companies working directly with the government on suppressor programs used Larson Davis 800B's and B&K 2209's for 1474-D testing. Very probably these companies realized that the testing was ultimately conducted by the military for selection, so it never really mattered whether they photographed a number or wrote it down.
5.2.5.3.1.4 Test personnel. Noise measurements shall be made with the minimum
number of people in the area, including test personnel. When noise is being measured in personnel-occupied enclosures, no test personnel or observers shall be present within the enclosure unless required to operate or adjust the test equipment, or to record data. View Quote That person would appear to be recording on paper, but maybe that person would be taking pictures of an oscilloscope as mentioned here: 5.2.1.4 Recording procedure. The pressure waveform shall be obtained by analog or
digital means. It may be displayed directly on a cathode-ray oscilloscope (or equivalent) and photographed, recorded with an FM tape recorder, or stored digitally. View Quote I'm more concerned with consumer reports style testing for consumers than with the minutia of military standards. I can't comment on what NATO or the military needs for sound testing (which is a shifting concept across time), but I can say that the suppressor industry has used 1474-D for ~20 years and that it provides single numbers that are useful to the consumer in helping to understand individual silencer performance. I would like to compare the B&K 2209 to the 2270 and Larson davis 831 to see how the numbers compared, and what the influence of ~30 microsecond rise time was, but that is as far as my interest goes. I don't want to change the standard that I've seen as easily used and understood by consumers researching products for ~20 years. As a company we realize engineers ultimately need efficient and reliable testing equipment, and often have to test off site, so portable equipment needs to be used for that. In that respect I wouldn't fault a company for running a Larson Davis 831 if they couldn't find a 2209. It doesn't help a company or an industry to force testing equipment on engineers that is so time consuming to set up that it reduces the frequency of testing in product development. As time passes there will be less and less access to the old analog meters that are considered 1474-D compliant. Unfortunately our industry demand for equipment is too small to drive equipment design. So I believe the most applicable and available portable equipment should be used, and everything I've talked about is a reflection of that in today's market. |
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[#37]
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I would like to compare the B&K 2209 to the 2270 and Larson davis 831 to see how the numbers compared, and what the influence of ~30 microsecond rise time was, but that is as far as my interest goes. I don't want to change the standard that I've seen as easily used and understood by consumers researching products for ~20 years. As a company we realize engineers ultimately need efficient and reliable testing equipment, and often have to test off site, so portable equipment needs to be used for that. In that respect I wouldn't fault a company for running a Larson Davis 831 if they couldn't find a 2209. It doesn't help a company or an industry to force testing equipment on engineers that is so time consuming to set up that it reduces the frequency of testing in product development. As time passes there will be less and less access to the old analog meters that are considered 1474-D compliant. View Quote I understand where you are coming from. It'd be interesting to see your results. My thoughts are that you will see more "erratic" data as the lower sampling rate hits/misses the peak but I would like to have data to confirm that hypothesis. I think the issue for me is having people understand the limitations of the equipment being used. Most people accept that the $25 noise meter they buy at the Val-U-Electronics Shop isn't suitable for testing impulse noise. But harder to understand that the $2000 impulse noise meter still falls slightly short of the standard and that if you can accept a confidence interval of +/- 6dB then by all means, go ahead and use it. My industry focuses on noise standards mainly from IEC60601-1. The money we spend on maintaining test equipment and sending out equipment annually for calibration and certification is insane. But we have to cross all our t's and dot all our i's or else the government gets very unhappy with us. This was an interesting discussion. And now back to the regularly scheduled Optimus show. |
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[#38]
Quoted: But harder to understand that the $2000 impulse noise meter still falls slightly short of the standard and that if you can accept a confidence interval of +/- 6dB then by all means, go ahead and use it. View Quote The 2209 is very accurate. We can meter the same can twice with accuracy of a couple tenths of a DB (same day/platform/ammo)- and that shows consistency of the 10round testing method as well as the meter. We can use the system to recognize performance gains in R&D as small as 1DB. All the systems discussed are class 1. I'm not sure how bad the meter would have to be to see +-6DB but my guess is all the discussed systems would be more accurate than that. |
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[#40]
Mil-std 1474-E has never been used as a silencer industry standard test. They could have made the number 1500KHZ, it wouldn't have any validity in my discussion as a consumer market silencer company representative. It is not uncommon for the government to ask for things that have no logical basis in reality. That doesn't mean the private sector has to pay attention or pretend like they made intelligent decisions. There is not one portable meter on the market capable of satisfying 1474-E. If someone working a hired job wrote that specification, his boss would laugh him out of the office.
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[#43]
Quoted: Mil-std 1474-E has never been used as a silencer industry standard test. They could have made the number 1500KHZ, it wouldn't have any validity in my discussion as a consumer market silencer company representative. It is not uncommon for the government to ask for things that have no logical basis in reality. That doesn't mean the private sector has to pay attention or pretend like they made intelligent decisions. There is not one portable meter on the market capable of satisfying 1474-E. If someone working a hired job wrote that specification, his boss would laugh him out of the office. View Quote Agreed. But it was to make the point that the latest revision of the specification did not relax the sampling rate. They didn't say to themselves "Yeah, 160 kHz was totally absurd." And even if 1474-E doesn't apply to the suppressor industry, 1474-D still defines 160 kHz as the minimum sampling rate. The paper I cited was directly related to gunshots and the technical requirements for accurately capturing a gunshot sound profile in the digital domain. Be it 160 kHz, 190 kHz, 200 kHz - it's all well above the 48 kHz sampling rate of some of the meters in use today. I believe I have also illustrated my point regarding the issues of under-sampling data. Like I said above, go ahead and use whatever hardware you want as long as you understand the limitations. If portability is the driving factor and none of the portable meters available today satisfy standards/best practices then the tradeoff should be understood. Personally, I've gotten to the point where a the "dB number" ranks pretty low on my list when considering a suppressor for purchase. |
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[#44]
Quoted: Nerds. View Quote This is much more interesting that sitting at the office running a Failure Modes and Effects Analysis (FMEA) while Dumb Ways to Die is playing through my head. |
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[#45]
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Agreed. But it was to make the point that the latest revision of the specification did not relax the sampling rate. They didn't say to themselves "Yeah, 160 kHz was totally absurd." And even if 1474-E doesn't apply to the suppressor industry, 1474-D still defines 160 kHz as the minimum sampling rate. The paper I cited was directly related to gunshots and the technical requirements for accurately capturing a gunshot sound profile in the digital domain. Be it 160 kHz, 190 kHz, 200 kHz - it's all well above the 48 kHz sampling rate of some of the meters in use today. I believe I have also illustrated my point regarding the issues of under-sampling data. Like I said above, go ahead and use whatever hardware you want as long as you understand the limitations. If portability is the driving factor and none of the portable meters available today satisfy standards/best practices then the tradeoff should be understood. Personally, I've gotten to the point where a the "dB number" ranks pretty low on my list when considering a suppressor for purchase. View Quote View All Quotes View All Quotes Quoted:
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Mil-std 1474-E has never been used as a silencer industry standard test. They could have made the number 1500KHZ, it wouldn't have any validity in my discussion as a consumer market silencer company representative. It is not uncommon for the government to ask for things that have no logical basis in reality. That doesn't mean the private sector has to pay attention or pretend like they made intelligent decisions. There is not one portable meter on the market capable of satisfying 1474-E. If someone working a hired job wrote that specification, his boss would laugh him out of the office. Agreed. But it was to make the point that the latest revision of the specification did not relax the sampling rate. They didn't say to themselves "Yeah, 160 kHz was totally absurd." And even if 1474-E doesn't apply to the suppressor industry, 1474-D still defines 160 kHz as the minimum sampling rate. The paper I cited was directly related to gunshots and the technical requirements for accurately capturing a gunshot sound profile in the digital domain. Be it 160 kHz, 190 kHz, 200 kHz - it's all well above the 48 kHz sampling rate of some of the meters in use today. I believe I have also illustrated my point regarding the issues of under-sampling data. Like I said above, go ahead and use whatever hardware you want as long as you understand the limitations. If portability is the driving factor and none of the portable meters available today satisfy standards/best practices then the tradeoff should be understood. Personally, I've gotten to the point where a the "dB number" ranks pretty low on my list when considering a suppressor for purchase. 1474-D (your citation above) talks about data recording (AKA capture of information from the sound level meter), 1474-E is talking about the actual sound testing equipment sampling of information. So 1474-D could be tested with a 2209 and a tape recorder or an oscilloscope like the military did do in August of 1968 during the Silencer Principles and Evaluations report and allowed for through 1474-D , but 1474-E appears to be made with the B&K Pulse system in mind. The military also doesn't manufacture silencers, and people usually get a pat on the back for constantly moving goal posts that involve solicitations because the military has an unscientific belief that whatever specifications they request will ultimately be achieved by the industries supporting their purchases and that the end result will be positive. Case in point the new modular handgun solicitation in which the military doesn't even want to rise to the level of responsibility required to ask for what it believes will be best- rather it asked for one gun that is multiple handguns in theory- a seat for every ass that I believe reduces the pistol to a soul less item like a screw-gun. Another point to keep in mind is that the only authority the military takes data from is itself. So you don't have to test to 1474-E to sell a product to the military or to win a contract with it. As an industry it will generally make more sense to test with portable equipment, or to at least have testing standards that support portable equipment. For that reason 1474-D is a sensible standard for the industry to have and it makes sense to me why we use it. |
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[#47]
First I don't want to hijack the thread and I like Griffin. Both brothers has been at my place and we have tested silencers together. They are both veterans and good people.
Second, no company/dealer who releases so-called silencer testing is doing it right. Period. The only companies that I know that are using digital sound meters that actually meet Mil Std 1474D or E is Surefire and AAC. The other digital meters being used are a joke. They are not capable of testing silencers as per 1474D or E. This includes every single test Silencerco has released, Silencer Shop released, Capitol, etc... They are nothing more than marketing meters. Doing 5 shot averages, not placing the distal end of the silencer at the same place for suppressed vs un-suppressed testing...etc.. its all a joke and is for marketing. The truth is that most people don't care. Most people buy into whatever marketing garbage they see and if some big company says it, well they know all about this stuff, so they are right. Marketing meters are cheap and make people think they are doing real testing. They are not. Its all marketing. Lots of people say dB's don't matter, or they don't chase dB's....or whatever. I don't blame them with the bullshit information that they have been able to get for the last 5 years from bogus digital marketing sound meters. There are many quality products on the market these days. As for how they actually perform with regards to Mil Std testing, you are not going to find any real answers today. Buy what you want and what you like, but don't take any of these sound tests seriously because they are pure marketing hype. Now back to your regularly scheduled dose of marketing madness... |
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[#48]
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First I don't want to hijack the thread and I like Griffin. Both brothers has been at my place and we have tested silencers together. They are both veterans and good people. View Quote I have not had the opportunity to meet them but I definitely respect their participation in this discussion. This discussion definitely isn't focused at or directed towards Griffin. I like their products and own a couple of their suppressors - well, I will once they get out of NFA jail. |
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[#49]
Quoted:
The 2209 is an analog meter and the AC output of the meter is still in the analog domain. http://i78.photobucket.com/albums/j88/Engineer303/ammo_and_guns_quotes/BK2209_Block_Diagram_zpsf3ya8vls.jpg So using a tape recorder (again, staying in the analog domain) is fine as long as the recorder has the proper frequency response and the output signal of the meter is matched to what the analog recorder's input levels. Everything is good as long as you stay in the analog domain. The terminology is the same in 1474D as in 1474E. The specific sections are calling out the properties of the analog to digital conversion process. I'm not looking to get into a debate about how the military does things or how they go about soliciting their proposals. I'm focusing on the discussion of using digital sound meters to acquire impulse noise data. It is not about performance requirements for something under solicitation but performance requirements for the tools that are used to gauge the widget being solicited. 1474D calls out a certain performance requirement which is also echoed by a technical paper outside of the military arena. If these performance criteria are not met, then the data acquired by the equipment is in question. View Quote View All Quotes View All Quotes Quoted:
Quoted:
1474-D (your citation above) talks about data recording (AKA capture of information from the sound level meter), 1474-E is talking about the actual sound testing equipment sampling of information. So 1474-D could be tested with a 2209 and a tape recorder or an oscilloscope like the military did do in August of 1968 during the Silencer Principles and Evaluations report and allowed for through 1474-D , but 1474-E appears to be made with the B&K Pulse system in mind. Another point to keep in mind is that the only authority the military takes data from is itself. So you don't have to test to 1474-E to sell a product to the military or to win a contract with it. As an industry it will generally make more sense to test with portable equipment, or to at least have testing standards that support portable equipment. For that reason 1474-D is a sensible standard for the industry to have and it makes sense to me why we use it. The 2209 is an analog meter and the AC output of the meter is still in the analog domain. http://i78.photobucket.com/albums/j88/Engineer303/ammo_and_guns_quotes/BK2209_Block_Diagram_zpsf3ya8vls.jpg So using a tape recorder (again, staying in the analog domain) is fine as long as the recorder has the proper frequency response and the output signal of the meter is matched to what the analog recorder's input levels. Everything is good as long as you stay in the analog domain. The terminology is the same in 1474D as in 1474E. The specific sections are calling out the properties of the analog to digital conversion process. I'm not looking to get into a debate about how the military does things or how they go about soliciting their proposals. I'm focusing on the discussion of using digital sound meters to acquire impulse noise data. It is not about performance requirements for something under solicitation but performance requirements for the tools that are used to gauge the widget being solicited. 1474D calls out a certain performance requirement which is also echoed by a technical paper outside of the military arena. If these performance criteria are not met, then the data acquired by the equipment is in question. I just wanted to clarify because really you are talking about a nuance of the testing and the fact that all the industry companies and also all the independent testing authorities (Al Paulson, Robert Silvers, John Titsworth) have historically read the dial and not hooked up the oscilloscope and taken pictures of the screen. I understand your argument. I'm glad I was able to get to the point I can say I see what you are driving at. I don't feel it disqualifies the statement the industry as a collective whole has made for the last 20 years, that it tests to Mil-Std 1474-D. I also don't see the data collection std which is unrelated to peak system rise time as a precedent to 1474-E for establishing that the peak system rise time was seen as not fast enough at 20 microseconds. |
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[#50]
Quoted: I just wanted to clarify because really you are talking about a nuance of the testing and the fact that all the industry companies and also all the independent testing authorities (Al Paulson, Robert Silvers, John Titsworth) have historically read the dial and not hooked up the oscilloscope and taken pictures of the screen. I understand your argument. I'm glad I was able to get to the point I can say I see what you are driving at. I don't feel it disqualifies the statement the industry as a collective whole has made for the last 20 years, that it tests to Mil-Std 1474-D. I also don't see the data collection std which is unrelated to peak system rise time as a precedent to 1474-E for establishing that the peak system rise time was seen as not fast enough at 20 microseconds. View Quote So the nuance with the B&K2209 is that the data acquired by the meter, in the analog domain, is accurate. The error comes from somebody's eye not being able to discern where that needle exactly is on the scale. With a digital meter, you don't get to look at the analog data. You're looking at undersampled data that's acquired and then processed in the digital domain. So the data acquired by the meter is inaccurate, but there is no inaccuracy associated with reading a number off of an LCD . Rise time and sampling rate are two different things when characterizing a DAC. A good explanation of the difference between bandwidth/rise time and sampling rate can be found in this white paper from National Instruments. |
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