As a sufferer of hearing disorders I’ll let you in on some magic, but not voodoo like @Foreigner 🪆:dash: 
Source, path, receiver
…is the order of priority
Distance, thickness, material
…is the order of efficiency in blocking the path
Memorize it 
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Makes sense to me. In my case the source was a fan on minimum, the path was the silencer and the receiver was Mrs Foreigner’s sensitive ear drums.
I have insulted ducting too but never got around to using it. It’s a bit of a bitch to work with.
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Is nothing sacred to you?
The insults never end.
I can get behind this idea. I leave my fan at 10-20%, like a gentle but persistent whisper.
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Nope. Nothing sacred. I went to midnight mass once and brought lots of whiskey.
In my defense it was such a short run of ducting that I just couldn’t be bothered and didn’t see the benefits in a cost benefit analysis.
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I have a bookmark of a good looking project for this if ever needed, I like that this guy’s coming at it from a speaker/audio designer standpoint like building driver enclosures.
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Oh I get it now. Fuck you ducting!
I’m a bit slow this morning.
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AFAIK the idea is like a sealed subwoofer, you need to have some pressure sealing to keep the noise inside besides dampening material to absorb
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Yeah going to try dyi muffler first then build something like the insulated tote idea
When talking to my neighbor we share a wall attached at the garages he only hears it when he’s in the garage
So if I move it off that wall try the silencer first then the box
I agree with distance is a factor that could help also
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I’ll also say, @Papalag that if you’re switching fans in the future the AC Infinity Cloudline I got to replace a cheap Vivosun is so damn quiet, though I did size it up and use a larger fan than needed so it runs low. I think they’re probably the most silent option you can get outside maybe commercial grade stuff and even that IDK.
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Yeah @Dirt_Wizard went the cheap way
I do own a 6 in ac infinity ,I use as in take and is way quitter then the 8 in vivosun there was a big difference in price
Oh well
I still have to fix it do think I can exchange it with Amazon
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Agree my AC Infinity is way quieter than my older fan.
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Yes, my 8" AC Infinity fan is quiet. The sound of that much air whooshing, even at 50%, not so much.
I did the DIY silencer on my old 2x3 cab and had decent results. It was large and cumbersome though.
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Most of the sound comes out of the fan axially.
As Foreigner said, insulated duct makes a big difference (& it is a PITA to work with).
Here’s some test data on a 6" AC Infinity to back that up:
AC Infinity T6 evaluation and test data
(see Phase II section)
Cheers G
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I can vouch for homemade tote fan silencers. It worked really good.
Using insulated ducts or abs will help…
Running a bigger fan with a speed controller does help…
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Reminds of my kid when she was little and the very same for me, when I was little. Kid not knowing that sound travels. Crinkling of the chip bag, carried through the silent house.
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I’m agree with @Foreigner and the others about using a bigger fan than you need and running it slower with a controller or variac.
Like @Gpaw i noticed most of the noise comes from the motor end of the fan, fixing the fan directly to the filter helps cut noise quite considerably, I’ve never used a silencer but they’re not too different to a carbon filter, can fan or rvk are better suited to fixing directly.
For my climate i get on much better now with slow and continous ventilation, i get the best temp/rh% figures and close to 0 noise.
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Thanks for all the advice
I did get the bigger fan with a speed controller and I am running it on low
I probably should have gotten the ac infinity 6 in and rrun it continuously
So plan is
Move it away From the adjacent wall first
Attach filters directly at the motor
Build silencer
Paps
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I did not read this but just looked through the pictures. Agree about it reducing noise. We did it at work (I was a part of a HVAC crew - controls - in a 3 million sq ft campus across 30 buildings), enclosed fans when they were in ceilings and were a problem for the people. I also like using a dense foam to put around ducting rather than fiberglass. The foam works well in the box also, carpet underlay could be used two layers better than one), check your local flooring place to see if they have scraps.
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