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.
Thanks for the ideas, but I'm not to the point of removing the case.
down clock it some more. and lower fans to 50%
Try freq 475 with a 45% fan it will give about 9.5 to 9.9th
Well I was running at 518 during the hottest part of the today (mid 90's F) and had the fan at 87% then bumped to 90% The siren was still there at either speed. The temps were acceptable between 90-94 for the chips. It's now midnight with out-outdoor air temps around 69.
I have bumped the freq back to 550 (default for this batch) and the chip temps are between 83-86.
It's running around 11.55TH which is acceptable.
Thanks for the suggestion, but I'll be damned if I'm going to run it that low (475) to make it run without a siren. I bought it to increase my hash as close to 12TH or more as I could get.
For now the little piece of cardboard I have taped to the top right quadrant of the out-take fan has stopped the noise.
My 12.93 batches don't make the siren sound, FWIW.
Seems like that was something Bmain should have fixed at the factory. But considering their apparent lack of caring about certain things, I'm not surprised.
Thanks for your suggestion. Tomorrow I'm going to cut a small square piece of mental to affix to the out take fan. And pray for cooler weather. LOL

Also, when it's out of warranty and the overall day/night temps are cooler , I'm going to bump the freq on that one to 587-600 and see how it behaves. Judging by the chip temps now with out door temps in the high 60's, it should run fine come fall/winter at the higher freqs.
Again, thanks for the replies.