Review on Noctua NF F12 Chromax Black Swap Premium Grade Quiet by Jay Lee

So that was the last item I installed on my new PC. They arrived forever (well, Revain forever. 10 days). Anyway, I just got it yesterday. I installed 10 of them in a Corsair Obsidian 1000D. 8 for front air intake and 2 for rear air intake. I also installed 3 140mm fans of the same brand and model on top of the tower to extract hot air. So my PC case has 13 Noctua Chromax fans. I also installed 3 Be Quiet fans inside the case on a dual tower CPU air cooler. That's 16 fans plus my GPU fan running inside the PC case. After installing everything last night, I also installed a decibel meter on my phone. I turned off everything in the house that could hear the noise. The decibel meter read about 30-35 decibels (low whisper) in the center of my computer room when I was standing still with my computer turned off. I turned on my computer, stood in the middle of the room, and tried the switch again. The meter still read 30-35 decibels. I went to the PC and put the phone on the case. I'm reading a steady 35 decibels. I opened the case and put the counter inside and then closed it again. The meter reads between 37 and 40 decibels (which still counts as a low whisper). At this point I would like to point out that my computer is running 6 14TB Seagate NAS hard drives. Although these drives are very quiet, I can feel them spinning while not hearing any of the fans I installed. In summary, these fans are so quiet that I would expect it to be quieter inside my PC case than outside when turning off my spinning hard drives. Also, after connecting 10 additional fans, I noticed that my PC case's idle temperature dropped by about 4 degrees Celsius on average (according to 6 sensors in a strange place and the motherboard's CPU sensor). It's not much, but then again, it wasn't exactly HOT at idle. I expect they will work fine when my machine is under extreme loads.