The Avenger sound test

The rifles used are a .177 (4.5mm) and a .22 (5.5mm) caliber. So, I measured the exit opening on each moderator to determine "up size" for this test. However, as stated in a previous post, I did 5-shot groups through my .25 Gauntlet II with each one and only had a single flyer the whole time. Obviously, "clipping" is not a problem with these cans and rifles.
Here's what I used in my testing:

9.77mm 0dBA 110C
9.59mm DonnyFL Sumo
9.57mm DonnyFL Shogun
8.57mm DonnyFL Ronin
7.95mm DonnyFL barrel adapter
7.92mm DonnyFL FX
7.42mm DonnyFL Tanto
6.73mm DonnyFL Tatsu
6.18mm Hatsan Air Stripper

To measure the noise these rifles made I put the SPL at 3 meters in front of and 1 meter to the left of the barrel. Then, firing groups and averaging the measurements, here are the results:

Air Venturi Avenger .177
Ammo: Crosman Premier Hollow Point (7.9 grain)
Stock: 100.1 dBA
eBay AV177 air stripper: 86.96 dBA
DonnyFL barrel adapter: 63.7 dBA
" " w/ Hatsan: 77.32 dBA
0dBA 110C: 63.42 dBA
DonnyFL Sumo: 65.54 dBA
DonnyFL Shogun: 74.12 dBA
DonnyFL Ronin: 70.94 dBA
DonnyFL FX: 71.78 dBA
DonnyFL Tanto: 71.92 dBA
DonnyFL Tatsu: 55.04 dBA

Air Venturi Avenger .22
Ammo: Crosman Premier Hollow Point (14.3 grain)
Stock: 73.44 dBA
eBay AV2 air stripper: 71.02 dBA
DonnyFL barrel adapter: 73.32 dBA
" " w/ Hatsan: 64.14 dBA
0dBA 110C: 77.94 dBA
DonnyFL Sumo: 73.22 dBA
DonnyFL Shogun: 78.64 dBA
DonnyFL Ronin: 77.28 dBA
DonnyFL FX: 62.8 dBA
DonnyFL Tanto: 75.04 dBA
DonnyFL Tatsu: 66.16 dBA

The weird thing, as you may notice, is that on the .177 adding an air stripper made it louder whereas on the .22 it was actually quieter. So quiet, in fact, that only the DonnyFL FX could match it! The other thing is that I'd been hearing negative comments about the DonnyFL barrel adapter/air stripper with some saying that it didn't help at all. Well, my testing shows that it does and, on top of getting better groups it allows the addition of a moderator, which the eBay unit does not. (accuracy testing will follow)

The testing here differs from the Gauntlet II testing in that here I averaged reports, but with the G2 I set the SPL to hold max. What I learned from watching the playback of each shot string was that the sound could vary by 50 or 60 decibels! I didn't hear that difference from behind the rifle. But, the variation could be due to variations in ammo-barrel fit, velocity (which I wasn't measuring), or simply environmental sounds that I didn't notice!

Nonetheless, I'm left wondering if I need to retest the G2. Perhaps even changing locations and trying to find someplace quieter to test at. (maybe Steve at AEAC would let me use his table in the trees?)

As always, I welcome your comments and suggestions.