NRR of 18 doesn't sound too good from a rifle-range point of view, unless I've misunderstood the meaning of these various figures.
https://www.earshotcommunications.co.uk/wp-content/uploads/2019/04/SWATCOM-Active8-UK.pdf
It really does seem that size matter with over-ear protection - and IMO the figures seem to bear out that the slim ones (except perhaps with plugs under them) are not adequate protection against rifle-bangs.
I agree. The Swatcom Active-8 appear to have identical performance to the Sordin Supreme Pros, i.e. on a par with or maybe a little worse, than Peltor SportTacs. As judged by both SNR and NRR ratings.
They do bring some nice features such as a more rugged build. The gel earpads are nice of course, but Peltor and I think Sordin can also supply replacement gel pads, e.g. the ones for the SportTac cost £32.50 plus vat. Whereas a standard "hygiene kit" of foam earpads, and the foam inner lings for the shells, costs £10 plus vat. No claims are made as to whether gel pads provide any more noise reduction, but certainly might be more comfortable, and possibly mould a little better around spectacle or eye protection frames.
So comparing SportTacs plus gel earpad upgrade = £159 inc. vat. with Swatcom Activ8 at £270 is valid, I think. Or you could buy two sets of SportTac, one with gel, one without, for the price of one Swatcom. Or nearly four sets of Protac Hunter. All nominally giving the same performance.
Saying that "sound level is limited to 82 dB (A) is misleading. That is simply where the limiter of the electronic circuits is set, and is a standard figure used by most manufacturers. It is similar to the threshold set for long term noise exposure at work before hearing damage starts (80 dB(A) or 85 dB(A) in the UK). In no way does it have anything to do with the attenuation provided by the muffs.
As regards wearing muffs on top of earplugs, as I suggested earlier it is good policy, and what I do at the range. However the total noise reduction is not a simple addition of the two ratings. The rule of thumb is that doing so increases the overall reduction by 5dB, based on the higher rated of the two. I'm not sure of the theory behind that, it seems a little simplistic.
Nevertheless say using 26dB SNR SportTacs over similarly rated earplugs might give a combined figure of 31dB. Similar to the physically larger 32dB ones, when used without additional earplugs. Higher rated earplugs would further improve that.
Both SNR and NRR ratings are measured using noise sources applying the A scale representing the response of human ears, which is far from linear. The actual frequency spectrum of the noise in the real environment is important, e.g. brushcutters, chainsaws, power hammers. rifles etc. are probably significantly different. It is at the lower frequencies where the attenuation is poorer than at the mid or high frequencies. This is documented in the data that I posted earlier. SNR measurements quote not only the single figure rating, but also ones for low, medium and high frequency performance. I suspect that the sound energy from gunfire may be more biased towards the low end.
