Ahh good information to know, so you don't think they are worth it? Maybe I should get something less fancy that has good noise/cfm ratio. lol
Right now I have 8 fans in my case all at full 12v speed and that's the only one that makes any audible noise.
I would suggest some Scythe Gentle Typhoons. AP-14s seem to be a decent tradeoff between noise and CFM. I believe they are around 50 CFM/ 21 dba.
The noise specs for the R4 must be for what they sound like at the lowest possible speed. There's no way they're only 19 dba. I have a Scythe S-Flex E in my case as the GPU intake fan on the bottom of the case and that's rated at 20 or so and it's tons quieter.