Noise Level Results
For the stock testing, the fans were spinning at near 1200 RPM and gave me a 29 dB rating on the meter. At this level, you really have to have your head within six inches of the fans to hear anything at all.
With 12 volts passing through the fans, and verifying a speed of 1795 RPM, these Helix fans do jump a bit in noise level to 50 dB. I test in open air, so of course I could hear it clear as day. Inside of a chassis and with the fans angled up to the top, you are likely to hear much less when in use.