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Even if you underclock and lower freq with original fans it's not what I would consider quiet (IE one I would want in a room I use much). Some have switched fans to much nicer and quieter ones that is really needed if you want more quiet not just bearable.
Avalon 4.1's still are king as far as quiet miners that are not to old. But they do cost more to get and only from used market.
At 2600 RPM i find them quiet enough. And soon i will be able to run them at the minimum, i think the firmware will let me run is 20% which should be about 1800 RPM. Which for me is very quiet.
Can't hear them at all in the next room. But keep in mind that for 2600 and less rpm i need outdoor temp of 5-10c fed strait into them. They're running at 387.5hz though, i didnt try underclocking them as well.
Temps are low too, 48c~ at 17c outdoor but 3000 RPM. I could probably lower them further but i like this target of 50c.
What I find quiet is having trouble hearing it in same room. I don't enjoy hearing miners to be honest.
That is part of reason I got a area just for mining. I might bring the Avalon 4.1's in during winter to heat a room or two. But most will remain in my mining area so I don't have to hear them.