Thanks for finding it. You know, I think I've actually seen that, ha. So... according to that review, the 17db Atom is indeed between the M15 and M20. I wonder if anyone out there who has used all three could confirm that? I've been thinking about picking one up. (I'm an M15 kinda guy, but sometimes wouldn't mind alternating by adding a touch more bass. But I usually find the M20 to be too heavy/smaller soundstage etc.)
Thats more or less True, I have all the Fir audio atom modules as well as the MX, m15, and m20 for my A12T, the fir gold(+) is just ever so slightly more open than the m20, but still more isolating than the m15 module.
The bass is slightly less attenuate as well, but there is still more bass compared to the m15 module.
Basically the FIR modules allow you to fine tune in between the 64 Apex modules.
The only exception would be the FIR red(0) vs the MX, where the MX kills the bass response completely.
The FIR audio Red is just as open and spacious as the MX module but still retains some bass.