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All Springer/NP/PCP Air Gun Discussion General > PCP/CO2/HPA Air Gun Gates "The Darkside"

20 Silencer Test

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mrbulk:

I have received several more silencers (or suppressors, moderators, LDCs, pickles, front-ends or whatever you want to call’em) so it seemed like a good time to do another sound output comparison test.

Key point - prior tests were performed with a shrouded .22 cal. Air Venturi Avenger.

There were questions about how the shroud might be “pre-silencing” the full air blast before it reached the external silencer, possibly favoring some silencer designs over others.

So for this new test I used a bare barrel airgun (no shroud or baffles), the Evanix AR6K Renegade in .22 cal. shooting JSB 18.13gr Match Diabolo Exact Jumbo Heavy pellets at 800fps making just over 25 FPE.

Un-silenced it was pretty dang loud and definitely not backyard friendly.

The gun’s air reservoir was recharged every 24 shots to ensure shot-to-shot consistency.

All silencers were shot through three (3) times each and the averages calculated.

An earlier test had the decibel meter placed approximately even with the gun’s muzzle and 6 feet off to one side.

A subsequent test had the meter placed 25 feet downrange and almost directly in the line of fire, to capture as much of the forward sound output as possible. This method seemed to spread out the max sound readings more, and made it easier to see the spread among sound outputs. In my opinion it made for a more accurate comparison.

So this time the meter was located a full 50 feet downrange and again as nearly into the direct line of fire as practical (without shooting up the sound meter). In other words, how loud would it sound to someone standing 50 feet downrange.

The meter itself was a Meterk Digital Sound Level Meter, Range 30-130dB w/Self-Calibrated Decibel Monitoring.

The pellet trap used was a duct seal “silent trap” with no target paper in front, so it was virtually silent and did not affect the sound meter’s readings.

And as it turned out, some silencers now showed better efficiency than before due to the way they were designed to muffle the full blast. Interestingly this yielded some different results from all prior tests.

=====================================

See the details about all the silencers tested, listed alphabetically (any commercial links are just what I could find, there may be others):

0dB (Zero dB):
Commercially available silencer.
See here for detailed descriptions and photos:

https://www.airgunsofarizona.com/airgun-silencers/0db-airgun-silencer-110c-black-with-1/2-unf/

Amazon Pill Box - Modified:
Modified from a screw-together aluminum pill box available online, in this case Amazon.
Modified build by private owner contributed for test.
See here for detailed descriptions and photos:

https://www.gatewaytoairguns.org/GTA/index.php?topic=180311.msg156046962#msg156046962

A.U.O.:
Finalized production version of the MM-1.
See here for detailed descriptions and photos:

https://www.gatewaytoairguns.org/GTA/index.php?topic=182312.new#new

DonnyFL Sumo & Tanto:
Commercially available silencers.
See here for detailed descriptions and photos:

https://donnyfl.com/collections/ldc

FX factory - Modified:
Standard factory silencer that came on FX airgun, with additional baffles added to certain sections of the internals.
Contributed for test by private owner.

Geo Short & Geo Hunter:
Commercially available silencers made of 3D printed monocore internals with a polymer shell and decorative vinyl wrap.
See here for detailed descriptions and photos:

https://www.airgununiverse.net/wp/store/12-20-hunter-class-ldc/

HT-68:
This large hefty unit is made of metal with extra wide & short proportions, created to facilitate use of an unnamed proprietary fluid to dampen harmonics and thereby improving accuracy in larger, more powerful airguns. Not specifically designed as a silencing device, although some sound reduction was noted as a side benefit.
See here for detailed descriptions and photos:

https://www.gatewaytoairguns.org/GTA/index.php?topic=181725.msg156068211#msg156068211

Huma 30mm - Modified:
Standard Huma silencer with partial replacement of the internals with 3D printed baffles.
Contributed for test by private owner.

Huma 40mm Standard:
Commercially available silencer.
See here for detailed descriptions and photos:

(USA) - https://www.trenieroutdoors.com/gear/airgun-moderators/airgun-moderators-3/huma-air-airgun-moderators/
(U.K.) - https://www.huma-air.com/Modular-Airgun-Silencers-or-Moderators#filter:9fcb43a01238ad8db1bd75a7a6370d97

MM-1 (Mystery Moderator 1):
3D printed proprietary internals, with end caps and body tube machined from 6061 aluminum, comes apart for maintenance.
Prototype of the A.U.O.

MM-2 (Mystery Moderator 2):
3D printed proprietary internals and end caps, aluminum body tube triple painted with one coat primer and 2 coats enamel.
Contributed for test by private owner.

Neil Clague custom build:
This is a build-to-order maker, the tested unit was built to handle airguns up to 50 FPE power.
Contact the maker directly online:
https://sites.google.com/site/ncairstrippers/home

Rocker2 and Rocker1:
Actually I do not know the model number, but since it was from the same builder as the Rocker1 (except a bit longer with improved sound dampening), I called it the Rocker2 to differentiate.
The builder is a member here, please do a search privately.
See here for detailed descriptions and photos:

https://www.gatewaytoairguns.org/GTA/index.php?topic=182340.msg156077081#msg156077081


STO Falx:
Commercially available silencer.
See here for detailed descriptions and photos:

https://www.silentthunderordnance.com/air/falx

TKO Slim:
Commercially available silencer.
See here for detailed descriptions and photos:

http://www.tko22.com/index.html

Wolf 30mm & 35mm:
Commercially available silencers from Poland.
See here for detailed descriptions and photos:

https://www.wolfairguns.com/index.php?cPath=32&osCsid=eg830cbqg305ls5c1a1gvrsdb7

========================================

Here are the results by category, beginning with dB (decibel) output averages of 3-shot readings:

Sorted by dB Low to High:

79.0 Huma 40mm Std
79.1 A.U.O.
79.4 Huma 30mm (modified)
79.5 Rocker2
79.6 MM-1
79.6 Neil Clague
79.9 FX Factory (modified)
80.0 Wolf 30mm
80.2 DonnyFL Sumo
80.9 Rocker1
81.3 0dB 110C
81.3 STO Falx
81.4 Wolf 35mm
81.5 Geo Hunter
82.9 Geo Short
83.3 TKO Slim
83.4 MM-2
83.7 DonnyFL Tanto
86.8 Amazon Pill Box (modified)
91.9 HT-68 Fluid Damped
105.2 bare barrel (meter overloaded)

Interestingly some of the louder silencers from the earlier test (shot from the shrouded Avenger), performed better in this new test through a straight barreled gun. For example the Neil Clague rose from 11th place to 6th when capturing the full air blast from the straight barrel.

The Huma 40mm Std did well in both tests, it was no.2 when shot through the shrouded Avenger and no.1 through the bare barrel AR6K.

The worst performing Wolf 30mm when shot through the shrouded Avenger, rose from 14th up to 5th when shot through today's bare barrel gun.There were more position changes if you compare the tests:

https://www.gatewaytoairguns.org/GTA/index.php?topic=180075.0

Sorted by PRICE ($):

27   Geo Short      
29   Geo Hunter      
49   Wolf 30mm      
59   Wolf 35mm      
59   A.U.O.
65   Rocker1      
70   Rocker2   
80   FX factory (modified)
92   TKO Slim      
99   DonnyFL Tanto   
120 0B 110C   
125 Huma 30mm (modified)
129 STO Falx      
135 Neil Clague      
150 DonnyFL Sumo   
160 Huma 40mm Std
n/a Amazon Pill Box
n/a HT-68
n/a MM-1
n/a MM-2

Sorted by WEIGHT (oz.):
1.7 Geo Short         
2.3 Geo Hunter         
2.9 TKO Slim         
3.0 MM-2   
3.3 Rocker1            
3.5 0dB 110C      
3.7 Rocker2
3.8 DonnyFL Tanto
4.1 A.U.O.
4.1 FX Factory (modified)
4.2 MM-1
4.7 Huma 30mm (modified)
4.7 Wolf 30mm            
5.1 Amazon Pill Box
5.9 DonnyFL Sumo      
5.9 Neil Clague         
6.4 STO Falx         
6.6 Wolf 35mm         
7.6 Huma 40mm
13.7 HT-68

Sorted by VOLUME in cu. in.:
(calculated from external dimensions only)

5.11   Rocker1
5.25   TKO Slim
5.49   Rocker2
5.68   0dB 110C
5.99   A.U.O.
5.99   MM-1
6.02   DonnyFL Tanto   
6.06   Geo Short      
7.33   MM-2
7.68   Geo Hunter      
8.32   Wolf 30mm      
8.72   FX Factory
8.96   Huma 30mm
11.25   Wolf 35mm      
12.10   DonnyFL Sumo   
12.44   Amazon Pill Box
12.70   STO Falx      
12.88   Neil Clague      
14.14   Huma 40mm Std   
15.70   HT-68 Fluid Damped

The sound deadening effect is dramatic going from bare barrel to almost any silencer. And it should be remembered that on the decibel scale, a doubling of intensity corresponds to an increase of 3 dB. This does not correspond to a perceived doubling of loudness, however. We perceive loudness to be doubled when the intensity increases by a factor of 10, which corresponds to a 10 dB increase.

Therefore, going from the bare barrel’s 105.2 dB reading (which could be even louder since it maxed out the meter) down to even the loudest silencer (91.9 dB from the HT-68) was more than 50% less in perceived loudness to the ear. It was a 13.3 dB reduction, or more than half the perceived loudness of the bare barrel.

Again it should be noted that in today’s test, by placing the dB meter almost directly in the line of fire of an un-shrouded bare barrel gun, the forward sound throw was more accurately measured and the loudness differences between the various silencers clearly magnified.

For example the spread between all silencers was only 12.9 dB (the HT-68’s 91.9 dB minus the Huma 40’s 79.0 dB) and the bare barrel output overwhelmed the meter into overload, measuring a maximum of 105.2 dB before the screen locked and started flashing.

Keeping in mind that a 10 dB increase creates a perceived doubling of sound to the human ear, this 12.9 dB spread means the output from the loudest silencer was more than twice as loud as the quietest. So the spread was easier to see when the meter was 50 feet downrange and almost in line with the muzzle.

It also appeared that silencers with more open internal structures that provide room for the incoming air to expand quickly, were more effective on shrouded or baffled guns, but units with more complex internals that directly engage the airflow and force it into convoluted patterns thereby delaying their exit time, seem better able to handle the full air blast from a straight barrel, while still working quite effectively on shrouded guns.

A few things I noticed among the units that seemed to be desirable:

Durability: Metal threads are preferable to synthetic ones for longer wear, and less chance of cross-threading

Disassembly Friendly: the ability to take the unit apart for cleaning and maintenance would seem important in the long run

Bang For Buck: how quiet vs. how much

Finally, please remember that these comparisons are for these particular units on this day with this gun shooting this ammo at this distance at today’s temperature, barometer, humidity and other associated weather conditions. Maybe even the phase of the moon and the tides, so YMMV.

Also rest assured that absolutely no science was harmed (or even used) in the completion of this test.
 ;D ;D ;D

CraigH:
Your efforts are to be commended, Charlie!

Great information for all interested parties.     8)

Lostkiwi:
Excellent review and really useful.

OTmachine:
Great review Charlie!  Thank you for your effort!  I wish that I had more time to contribute to the hobby.  Airguns are Great for Tinkering.  I am changing out my Sentry’s shroud for a CF tube for experimentation. 
Thanks again!
Keith

avator:
Dang Charlie.. You put some time and effort in that.
Greatly appreciated !

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