Moderators - Sound off

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rangur1

rangur1

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Jan 4, 2018
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peoples republic of New York
ran a quick test of comparative moderation, test guns were FX Wildcat mk11 and taipan veteran long. both guns are 25 cal , this is how different brands/models fared.

Wildcat Taipan vet long

no mod 112 db ave 110 db ave

donfl shogun 98 db ave 94 db ave

donfl ronin 98 db ave 93 db ave

donfl emp v2 96 db ave 91 db ave

0 db 1 1/4x6 1/2 101 db ave 99 db ave

huggett 1 1/4x 6 1/2 100 db ave 96 db ave



all testing was done dry fire, i'm sure that can make some difference, but as for comparing each of them, conditions were consistent. i am sure the donnyfl sumo would be right where the 0 DB and hugget were. all these brands are spot on and it seems to come down to preferred looks and service-which donny fl wins. as for cost. the ronin, 0 DB were about same, huggett was $60 more but may have come down in price since i bought mine .
 
Clearly shows how the effectivity depends on the gun.

What we really need is a plot of the SPL as a function of frequency for the gun itself and then the same with the selected moderator.

Moderators will have natural "resonance" frequencies where they will have high attenuation and other frequencies with less attenuation.

Guns, likewise, will have sound output that varies with frequency.

Mapping the two overtop of each other is what we hear and what we are all trying to mentally do when making a purchase decision - basically impossible without good frequency-domain measurements.




 
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Interesting, I'm sure there's lots of variables (shroud,velocity,barrel length, etc. Either way looks like the emp v2 wins. Im pretty sure they are quieter when shooting pellets. Thanks for the comparison.
Click to expand...

the emporor was figured to win, it's a 10x2" mod, both guns shrouded, but i was a bit surprised it was that close, but then again, these are not hatsan or airforce were they are real loud. so the effect may be less on the 2 guns i had.
 
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What instrument were you using to measure the moderators? What was your test distance? (muzzle to meter) I ask because the overwhelming majority of meters aren't able to accurately capture the peak sound pressure. I did some testing which demonstrated this issue:
https://www.airgunnation.com/topic/fx-crown-bespoke-moderator-tesla-gas-diode/page/3/#post-423262



So I actually just raised this issue to our friend Steve from AEAC who runs an Extech 407730 which is a very nice entry level meter, but even that is totally un-suitable for measuring moderator peak outputs. That meter has a response time of 125ms and a maximum frequency of 8khz. (ref. page 3 on the product manual http://www.extech.com/resources/407730_UM-en.pdf ) Compare that to the trace below, where each vertical grid line represents just 1ms and you can clearly see it isn't going to capture the peak. And that is a much nicer meter than many people use. 

1553817866_9438596955c9d610ad16071.19700059_Donny Sumo.png


Why do I bring this up? Because unless you're using one of just a handful of pieces of fairly exotic equipment, you'll be missing the peak (highlighted below in purple) and instead what you're comparing is something highlighted somewhere in the blue. This is another interesting aspect of moderator performance, how quickly and quietly the moderator tapers, however it isn't the same unfortunately. If you're interested, I have complete traces on several of the moderators you tested above, which you can find here: https://www.airgunnation.com/topic/fx-crown-bespoke-moderator-tesla-gas-diode/page/5/#post-453278

1553818038_5755646035c9d61b6a58d94.45409411_cell phone measure.png






I hope that helps. :) I realize sound is a complicated and confusing thing, particularly when it comes to impulse sounds like exit our rifles. 
 
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Anyone tried the Trident? And, what are the internals of the Trident made of that are destroyed by regular firearms ... Plastic? And is that a concern on higher caliber/power airguns?
Click to expand...

So I should have a Trident on the way to test. I think it is a really exciting looking design, one of the few on the market which is innovative and novel in its design, but as I'm sure you've noticed there is basically no information out there about it. When/if I get it (never count your chickens) I will test it and post the results in my big moderator testing thread. 



I will say I really wanted to test a Ramus Trident my first time around, and even asked for one specifically to borrow but NOBODY seemed to have them, or at least nobody willing to trust a lunatic like me to borrow it. ;) So hopefully it performs well and I can finally get some good data out there on it. 



As far as how it is made, I have some guesses but I'd rather wait and give answers than post possibly wildly incorrect speculation now. ;) If I'm right though, it should have reasonable enough durability to handle your typical airguns. Obviously you can always bore/air up until you break something on any moderator but...... 



I hope that helps. :) 



*update*
Trident showed up. Initial impressions are very positive. The whole thing looks nicely made and is much lighter weight than equivalently sized mods from other brands. Testing will take some time but for now I have no complaints. :) 
 
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I have been finding that the point of impact is much louder then my guns, anybody know how to make a silent backyard friendly target to go with those super quiet moderators. rangur1 thank you for the info.

Using a DonnyFL Koi on .25 Wildcat II, the sound of a taget hit is louder than the shot report. I've been using an orange "Homer" bucket filled with the rubber mulch. When the snap on lid gets too porous, I tape a piece of cardboard inside the lid. Or, they sell 10 and 20 packs of the lids.




 
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STO touched on this, so I wont. Also affecting YOUR perception of how loud/quiet a LDC is, will be WHERE the shot is taken (in my garage is louder than outside, outside means sound reflected off the building close by, shots taken at midnight vs rush hour)

I ve got a Form-1 .22 LR that will measure lower dB than my TKO on the same gun, but it seems louder than the TKO under the same conditions. (FWIW, on my 10/22 its dead silent) Lower db is only part of the equation, what the device does to the TONE of the shot is a huge factor also. IMO its the TONE that we perceive as a significant portion of "loudness".

Ambient temps and humidtiy will affect sound too....... 

When we discuss this topic we should agree on some things to mention: The device used, where it was tested, time of day, temp, humidity. Then we can get sense of apples to apples......

and almost forgot, BIG thanx to Rangur1 for doing the comparsion tests. ANY data contributed is helpful to us all........



edited for spelling, grammar, incomplete sentences
 
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