Phone apps are notoriously inaccurate and not apples to apples. I do not need an app to shoot CCI Quiet right next to my M-Rod to see which is quieter. I will save you the suspense, it is the CCI Quiet. Even with a DFL Tanto on my M-Rod the CCI Quiet wins.
^^^ What he said. Phone apps do not check to see if they overload the front end. Once that happens, you can't compare results because your data is clipped. Clipped data means the information has been removed from the signal. This means you don't know how loud it is anymore, because the loudness information was thrown away by the clipping. The information is
irretrievably lost. The app can't have any true idea how loud it was, in the presence of clipping.
It's hard to truly measure airgun (or PB) reports with any fidelity. A simple app can't do it. Not saying a sophisticated app won't work, but good apps involve very special signal processing or expensive data capture equipment or both. I've tried monitoring close range reports with a calibrated audio microphone, and 99.9% of the time, the recorded signal was clipped. You have to move the microphone quite a long distance away, or you have to greatly attenuate the microphone output before data capture. All those things dramatically increase your measurement uncertainty, making it tough to compare calibrated results. You need to religiously follow a lab check list, with zero deviations, to get any hope of repeatable data. Most people won't (or can't) do that, which basically makes their data set incomparable to other collected data.
It's a tough problem to faithfully digitize impulsive sound. The sound has a high dynamic range, which means expensive components are required to capture it with full fidelity. I looked into it, for the purpose of measuring moderator performance, and rapidly found out, it's an expensive proposition, requiring a bit of gear that I just couldn't justify the investment. Even with the equipment, it's really tough to do indoors, with echos off walls, and ceilings, and not all that easy outside either. (Echos off houses, fences, target backstops, whatever.) It requires time gating, and intimate knowledge of your local environment (echo removal). Not saying an ordinary Joe couldn't attempt it, but they'd have to have extraordinary technique to get valid data.
I fully believe
@3Crows assessment of the CCI Quiets. Hmm, maybe I should get some for myself, you know for the sake of experimentation.
The human ear is darned good at telling moderate differences between sounds, especially if done in rapid succession.
