Some quick moderator numbers.
My STO Accipiter came in today. I got the Falx size, standard flow .22 cal for my Avenge-X .22 - this is as simple as this post is going to get, everything from here on gets more complex, but if you bear with me I'll try to provide some information that might be helpful to other people looking for a moderator or wondering how to interpret moderator reviews or comparisons. I want to preface everything you're about to read with "I have BS in Audio Engineering" (I'll wait for the not another engineer groans to die down before continuing)
First a word about Decibels. This is not a linear scale, it is logarithmic. In short, a 3db change in sound, although technically a doubling in sound power, is considered the smallest change the human ear can discern. A change of 10db is a tenfold increase in power, but only sounds twice as loud to the human ear. The same thing applies to reductions in sound levels, just to be clear, since we are obviously hoping to be talking about reductions since we're talking moderators.
I took my db meter and a video camera into the back yard, put up a paper target, and set the db meter and camera up 3 feet in front of the gun, slightly to the side, with the gun on a tripod at 50 yards from the target. Unmoderated, I got 95db over a range of several shots. I then moved the db meter and camera to 20 yards from the target, so, 30 yards away from the gun. From there I got 86 db on a series of shots.
Before I go on, I want to talk about the db meter for moment. Please, no one ask if this meter is calibrated. It's very nice meter, but it's probably older than about half of the people posting here - I wouldn't give a plug nickel for this thing having the CORRECT db for a given sound - but I will bet that the ability to accurately document the relative difference in two sounds is incredibly good. And that's really all we care about here. The difference. That said..
This indicates that the sound of a shot from the gun is half as loud at a distance of 30 yards as it is 3 feet from the muzzle. So I installed the STO Accipiter, and repeated exactly the same process. The results surprised me a little. From behind the gun, all I could really hear was the hammer spring and other mechanical workings of the gun. Good. From in front of the gun, I recorded a level of 84db. That means it's a little better than half as loud. At 30 yards from the muzzle, I was surprised again - 71db. That's significant, and quieter in a non-linear way from unmoderated.
Of course, I have no other moderators to compare - but if any of my talking about the numbers helps anyone understand other reviews or comparisons, that's good. Also, I would like to say, I was most shocked by something that had nothing to do with sound levels while doing this. I fully expected to have to re-zero this rifle. In fact, the only change in point of impact from the zero without the moderator, is maybe 1/4 moa to the left. Too small to even adjust out with my scope.
I'm sure I've left out something someone is interested it, so I'll try to follow up questions. And no, I didn't (and probably won't) post the video, as it was really only there to give me a way to see/record/remember the numbers on the db meter. You'd literally just have a video of a db meter display that means nothing with this post, which covers ..well, everything in the video anyhow.