Also, it doesn’t seem like a huge difference, but here is the Braiins dashboard for the bungee vs the 3D printed adapter. It’s only a 200-300 rpm difference, but any increase over 1200 becomes VERY noticeable in a bedroom. The sound profile also seemed a bit harsher with the adapters - not sure what caused this. 
Discussion
wow, I run my s9s at 700 too - had to double take this because it looked like mine. I run stock fans, will compare tomorrow
I did also replace the psu fan with a noctua. Doesn’t impact this discussion but makes a big difference in sound. Right now I’m about 6 ft from it running at 700 and my iPhone is reading at around 37 db. I don’t know how accurate these apps are, but it is quiet enough that my wife is able to sleep which is all that matters.
looks like those fans do make a difference. this one runs in a room void of rugs, sitting on hardwood. 
You could try upping the target temp (mine is at 94 C) to see if the fans have to work less, but I bet this is primarily a difference in fan size 140 vs 120 and noctua vs stock for the db level.
I probably should keep it off the carpet honestly, but I have found if you stack the miner with the PSU on the bottom and add some rubber padding the ground will barely get warm from contact during normal operation. 
I have the miner rotated 90 degrees from how I normally run it above. Hopefully I’m not doing something incredibly dumb here
I am super excited to see what you get with stock! I am using the NIOSH app for sound measurement though I’m sure our comparisons won’t be exact since the mics aren’t calibrated.