On the S9 controller there is two fan connectors but the board have place for 6 others fans connectors.
Do you know if these connectors placeholder receive power? If yes would it be possible to add fan connectors.
Here is an idea for a quieter miner. Remove the case and have 2 fans pointing directly at each blade sideways. So the fans would be pointing directly over the heatsink. With this setup I'm sure it would be possible to use lower cfm fans (quieter). 6 quiet fans is a lot better than 2 jet engines. Anyone tried this?
If the controller cannot power more than 2 fans it is possible to use a 1-to-3 splitter to power 3 fans per connector.
The case serves a cooling function too - directs airflow and probably dissipates heat as well. I would be very careful with a mod like that. Among other issues you'd likely have hot air getting mixed back into intake.
I posted this earlier in the thread, but I think it got lost in the excitement of new S9s. With the original S1s, there was a mod that worked quite nicely. You could take them apart and put a 200mm fan on each blade to cool them effectively but silently:
https://imgur.com/a/RUAX5I did this with my old S1, and it worked amazingly. The miner ran at full speed, with a better temp than the factory fans, and it was totally silent unless you were standing right next to the fans. I'm going to wait another month or so until my warranty expires, then I'm going to try the same thing with my S9. Particularly with the thermal throttling built into the S9s that protects them from overheating, I'm confident this will make for a better mining experience. My only concern is finding another "base" for the third module in the S9s.