Ender 3 - Simple Fan Shroud (40x40x20, silent)

thingiverse

This is a straightforward and efficient fan cover, similar to the original but with additional space for a 40x40x20 fan. The 40x40x20 fan outperforms its smaller counterpart by a significant margin, making it an ideal choice. To further minimize noise, you can install a buck converter in front of it, resulting in a much quieter operation. However, do not consider adding any protective measures in front of the rotor, as this would compromise the fan's performance and potentially lead to excessive vibration and noise due to its high speed and small size.