How to quiet down an S9?

Has anyone swapped the fans for quieter options? Thinking about using a Noctua fan (the RPM is lower) or even removing one or two hashboards. I'm mining in my apartment, so I really need to cut down on the noise.

there are multiple threads on low powered s9 builds. https://bitcointalk.org/index.php?topic=5160194.0 that thread may help

There are many ways to run the miner with less noise you can either build a soundproof box or liquid cooling. There are many guides here on the forum on how to do that check this one below - https://bitcointalk.org/index.php?topic=2666719.0 Other guides are also available on Zeusbtc below - https://www.zeusbtc.com/articles/maintenance-and-operation/2277-practical-methods-for-noise-reduction-and-cooling-of-asic-miners

Thanks, I checked out some of your videos I might try one hashboard. Did you change the stock fan? And what worked better, Hashboard in the middle or off to the side when it came to keeping the hashboard cool with wood added?

I didn't add wood, just cardboard and tape (since the exhaust fan was removed). Yes, merely blocking the extra empty space does the trick. Don't do it and it overheats. Works like magic (at least a year tested).

A definite improvement on my idea. As it is easier and cheaper. Also do no use the apw3 psu get something like this one. https://www.bestbuy.com/site/corsair-rme-series-rm750e-80-plus-gold-fully-modular-low-noise-atx-3-0-and-pcie-5-0-power-supply-black/6537989.p? this is a good 1 board psu very quiet. it can do 2 boards if you use brains  and set to low powers (under 500 watts)

I changed the firmware to Brains OS and set a power draw target of around 750w which gets about 10th. Removed the front fan and just used the rear fan. Use an HP Common Slot PSU with breakout board and custom cables. Runs cool and quiet, although I only ever use it now when its cold as a space heater.

I wonder if anyone has tried underground mining to cool their miners in the form of a basement and ground-coupled heat exchanger which cools down the basement? Or would that be insufficient cooling? As far as OP's question goes, I would wager liquid cooling to be the quietest method for cooling your mining rig. But then again if you have an entire room of miners, I am not sure how exactly that would differ from fan cooling. You would still need a source of cool air/liquid in both cases, I imagine. Perhaps combined with an more efficient way to channel the electricity through a minimal energy loss system. I don't suppose anyone mines with superconductors ?

It's super easy - heat water (TAP water or anything that needs heating all year long). Swimming pool? Not a problem, we have done it. Paweł FlameIT - Immersion Cooling