Nice work MrBulk.A word of caution with the new sound meter, make SURE the range is set correctly for each and every shot. I somehow made an error when testing with my Extech 407730 and ended up with lower than normal measurements (all those darn buttons [size=78%]). [/size][/size]I suspect my test SHOULD still represent the discharge sounds in a ratio from one LDC to another LDC, just not at the right 'number' for an actual reading. (if that makes any sense)[size=78%]Yes Matt thanks, I plan to use my new meter to present both A- and C-weighted readings for the readers' own interpretation, but will keep the sampling rate at the faster 125ms rather than just once per second. Also the ranging feature will help keep the expected output noise levels within a narrower, 50 dB spectrum which helps the meter concentrate on more accurately reading results within a specific sound intensity range.Another observation I just read and made was the impact noise effecting the sound reading. I was lucky enough to have my backstop hundreds of feet beyond my meters when I did my tests. There was virtually no impact noise to affect the overall quality of the test. Another interesting test might be to take a DB reading with the backstop where it is, then try taking a shot into a clearing to see how much of a DB difference there is. Of course, much like my test, all things being equal for each of the 'test subjects' the comparison between each should be representative of how they perform to each other regardless of what the actual reading is.Oh, I knooow and as I said before, in a perfect world... But seriously I have made up a large layered sack of old clothes and will be firing into that (with a sturdy backstop behind) in the next test. Test shots so far have ensured it is quite silent. At first I tried stacking the clothes in a cardboard box, but the box itself would still help produce a low "Foomp" noise like a very quiet bass drum, so I took all the clothes out and wrapped them up with a large bed sheet and am just shooting directly into that now.One thought also just crossed my mind as far as measuring sound DB down range. How much effect does the shape of the pellet/slug make a difference to the DB output down range? At a far enough distance, you might well be hearing the pellet noise in flight and the impact over the discharge noise. I suspect that is why most manufactures test the performance of a suppressor closer to the muzzle so as to test how it suppresses discharge noise, as their main concern is suppression for the shooter. Though it is always good to know what the neighbors might hear as well, since it is the primary concern of us airgun shooters.I am fairly confident the sound of the muzzle blast far exceeds any sound the pellet makes, even when passing within inches of the meter, otherwise all of the sound readings would be the same since I am only using identical 18.1-grain pellets for every shot plus the meter locks in the max output it detects. But even if different pellets did make a difference, using the same pellet for everything would still make the comparison valid I feel.Also when I was placing the meter directly to the side of the muzzle and about 6 feet away, it may have been picking up incidental noise from the gun action itself as the readings were all much closer, especially for example when I was using the Evanix AR6K revolver-action PCP, which had some blowby on each shot from gas escaping between the cylinder/breech seal. Next test will use the regulated FX Wildcat MkIII.I think everyone (including myself) will be looking forward to your future testing at higher FPE levels, as it was one of the criteria I HAD planned on testing with my AirForce Escape after my original Maximus LDC project (but never found the time). Kudos to you MrBulk for running with the job of testing every LDC under the sun and posting your results.Thanks Matt, although I might leave testing significantly higher FPE guns to someone else, I just simply don't have the room (nor neighbors tolerant enough) to go too much further up the power scale. Besides, this whole journey began when I decided to find out which silencers would work best in my particular guns, so right now I am already in my happy place... Cheers,M
WHY do I keep clicking on this thread?!? 😟
Quote from: JungleShooter on February 07, 2021, 08:50:47 PMWHY do I keep clicking on this thread?!? 😟 Because you automatically receive notifications to subscribed threads. You can always click "un notify" if you like. I do that with any thread that no longer informs or amuses me...
.... I'm also happy to announce, it has found a permanent home on my .22 DAR......
One thought also just crossed my mind as far as measuring sound DB down range. How much effect does the shape of the pellet/slug make a difference to the DB output down range? At a far enough distance, you might well be hearing the pellet noise in flight and the impact over the discharge noise. I suspect that is why most manufactures test the performance of a suppressor closer to the muzzle so as to test how it suppresses discharge noise, as their main concern is suppression for the shooter. Though it is always good to know what the neighbors might hear as well, since it is the primary concern of us airgun shooters.
Interesting you brought that up. It would be cool to get a gun quiet enough to actually measure this. CPHP 14.3 pellets can be a bit noisy at high speeds. I've also shot some RWS 12gr wadcutters, and they seem to be quite noisy as well. I don't think they're intended for much over 600fps if even that.
But don't shoot the mic.
Thank you mrbulk for your work and the good information.
Advertise Here
Share This!