Since I had three fans to connect, when running the stock tests I only allowed the fans to receive 9.5V to achieve these results. Even so the fans are audible, but just ever so slightly at this point. The 31 dB rating is what you would get with these fans running roughly 1100 RPM.
Sliding the sliders to maximum on the fan controller only supplies 11.83V, but at near 1650 RPM, the fans do increase in volume. I do like that they aren't out of control loud, more along the lines of average with a 52 dB rating with the overclock applied.