Not quiet enough on the left had side of a tower case.
Perhaps the case acts as a Helmholtz chamber and resonates with the fans?
I would have preferred fans with a 4 pin connector (the motherboard controls the fan speed) but right now electronic stuff is as available as rocking horse poo.
I am an Electronic Design Consultant and supply hurts, weekly requests from customers for alternate component sources - ?search the web, I have already provided all parameters? but sadly so called engineers are not really competent.
Guess why clients outsource design projects.