Good airflow for such a quiet fan.
I have 3 connected with speed control from the motherboard, set at 40-50% of the speed until the CPU (AMD 5900x) or GPU (Intel Arc A770) temperature rises.
In 80% of cases, with usage in office apps, programming, video editing, and occasionally racing sim, they don't bother me -- with the PC 1.5 meters away from my ears, at desk height.

Disappointment. Having always had Noctua cases for many years, this was the first product that disappointed me a lot. With already two NF-A14 in the front for intake and one NF-A12 in the back as exhaust, I decided to get two more 14s for the top. Since the cost of the A14s is high, I decided not to spend much and go for the redux, not needing a large airflow for the top, just for supplementary operation. One of the two worked as it should, but the other one was returned immediately as it made a constant ticking sound as if it was "hitting" something (without anything visible, some fault in the motor). Its replacement was even worse, it wouldn't turn. To make it turn, you had to nudge it a little with your finger, which obviously you can't do every time. Note that it was placed in the same slot as the other redux that works fine. I threw it away, I got tired of dealing with it. Conclusion: Either go for the "regular" series and pay what you need to pay, or go for another brand/model (e.g. Arctic) that works just fine for half the price or less.