I guess the question I’d have is — if possible, can you post the fan’s manufacturer/model number so we can at least look at the current specifications without having to open up a 9000 ourselves?
Here is the datasheet, so if you wanted to install a different fan yourself, you have the information you need. This should not be construed as a recommendation to do so.
Our fan is rated 14.3 dBA, which, according to Noctua’s specs at https://noctua.at/en/products/fan, is quieter than all their 80mm fans with PWM. (However, making absolute measurements of acoustical levels is very dependent on setup/calibration).
Yesterday I did some work to enable the PWM controller on the H9000 and found that reducing the speed makes a big difference to the noise, while keeping the temperature of the DSPs at a reasonable level, at least in my home office environment. This will get released soon, after we do a lot of testing to make sure we won’t overheat.
