[SOLVED] How to reduce the fan noise without slowing down the fans?

[yargd]

Thank you

 

[Gam3r01]

Generally there are a few ways, none of them are "good".

One option is to sound dampen the case, adding foam sound dampening and such inside the case, this however restricts airflow, which defeats the purpose because you could get the same result by just turning down the fans.
Fans could be unbalanced or very cheap, thus creating excess noise, which would mean replacing them with fans that are working properly, this however requires proper diagnosis and isnt common.

Easiest: Buy quieter fans.