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Posted: 8/29/2026 8:38:24 PM EDT
[Last Edit: hhsmiley][Edited]
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Hypothetically, if a person were to take advantage of the current situation regarding the NFA to buy or build .22, .556, and .308 silencers, is there a relatively inexpensive way to accurately measure the sound levels in DB? My initial research indicates that phone apps and inexpensive meters are just totally ineffective for this, and that meters that actually work are very expensive. Is there some cost effective work around? |
The more the government tells us we should not do a thing or have a thing, the more crucial it is that we do those things and have those things.
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The cheapest and easiest way to a reasonable, peak dB respected-but-old-school yardstick is to buy a B&K2209 off eBay. There’s a guy in Hungary that finds old ones and refurbs them. Seems to do a good job of bringing them up to speed. Not a bad deal, all said. Add a 4136 mic and you’re 1992 state of the art. |
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The sound of a gunshot happens WAY too fast for an el cheapo meter to accurately measure its pressure wave. The Mil Std requires measuring at 192,000 measurements per second. That is that is minimum spec meter that you need to use. TBAC and Griffin have made videos about this, Jay/PewScience has loads of info about it. The meter that TBAC is using measures at just over 262,000 per second. Jay's meter is 1 million per second. And if you are gonna compare cans to the nth degree, you need to do an apple to apple test, so same environments, same ammo, same hosts, etc. |
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Originally Posted By Arete: The sound of a gunshot happens WAY too fast for an el cheapo meter to accurately measure its pressure wave. The Mil Std requires measuring at 192,000 measurements per second. That is that is minimum spec meter that you need to use. TBAC and Griffin have made videos about this, Jay/PewScience has loads of info about it. The meter that TBAC is using measures at just over 262,000 per second. Jay's meter is 1 million per second. And if you are gonna compare cans to the nth degree, you need to do an apple to apple test, so same environments, same ammo, same hosts, etc. That Mil Spec is either intended for something else or the quote is in error. ETA: I looked it up. The only reason Mil Std 1474E requires 192 kHz is for very precise resolution in time of the gunshot. There is absolutely no reason to acquire at that rate if all you're doing is comparing the audible performance of one suppressor to another. Applying any weighting scheme will cut that data off anyway. Common standard in measurement of any dynamic event is 10x the sampling rate of the highest frequency of interest, and even that is 5x the Nyquist-Shannon standard of 2x oversampling. You need 10x when you're really splitting hairs, doesn't sound like what the OP wants to do. 192,000 Hz would be sampling a 19.2 kHz sound 10x, which is just shy of the theoretical upper limit of human hearing of 20 kHz. I can find no data that suggests even a pistol shot has meaningful sound energy above 10 kHz, with the vast majority of energy concentrated below 2 kHz for all calibers, including shotguns. The general standard established decades ago is that to adequately measure what a human will hear, you need no more than 51.2 kHz sampling rates. Frankly, the YouTubers are just trying to wow you with big numbers because they can, and your likes and subscribes support them buying that unnecessary gear. OP, you really should ask a mod to consolidate your two threads on this same topic. |
| The 821H-QPR is apparently a 30micro second rise time (~33KHZ), and $4050 cost so that's a pretty affordable practical meter for the field compared to other larson systems around $8000 doing basically the same thing. The $125 rental fee is pretty affordable for something that costs $4050. |
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Originally Posted By kel: The cheapest and easiest way to a reasonable, peak dB respected-but-old-school yardstick is to buy a B&K2209 off eBay. There's a guy in Hungary that finds old ones and refurbs them. Seems to do a good job of bringing them up to speed. Not a bad deal, all said. Add a 4136 mic and you're 1992 state of the art. |
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Maybe so, but circa my randomly-picked date of 1992, I don’t know anyone in the silencer industry that WASN’T running a 2209, or the far-rarer 800B, or good ol’ OPS-Phil with his oscilloscope. This predates me a bit (I’m not THAT old), but pretty sure Qual-a-Tech, Reed Knight, Walsh, et al were rocking B&K’s back then. I’ll have to ask Jon Ciener next time I see him what, if anything, he used back in the dark ages. The first time I recall seeing a DAQ offered as an alternative to the tried and true 2209 was ~2006. Maybe Rob Silvers was talking about A-D converters at some point, but used a 2209 for his SilencerTests metering site. Silencerco in 2010 announced their digital setup. This, of course, generated controversy because the silencer industry was well-populated with egotistical keepers-of-fire leery of change they didn’t initiate or bless. :) |
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