My dust collection is louder than my cnc, so im trying to quiet things down without restricting air flow. I figure 180 degree offset outlets might help. I’m hoping for a 10db reduction, but quick design on tinkercad and printed in pla… Will it work? Updates
Put me down for “Whistles louder than the output air was” 
Hopefully you find a good solution that works. Mine was MUCH more expensive than what you are doing. But it’s also nice and quiet lol
Home Depot sells a shop vac muffler. It’s a small plug with a foam filter on it to help slow the airspeed down.
If you have any open cell foam, you may be able to try stuffing some of that in it. You can get large open cell foam at aquarium/pet stores. It’s sold as filter media for aquariums.
I have one of these and it does help some. It’s still loud. But not near as loud as without it
10dB is a huge amount. Hard to see that as possible.
I’d probably grab an one 2.5" spare muffler from the garage.
I’m pretty sure I have this one. It takes it from, “Ow, my ears!” To “What?!”
DB are logarithmic. 10db would cut the volume in half. It’s a lofty goal to say the least :laugh"
I didn’t get 10. But i did go from 85-87 to 80-82, noticeably better. I’m going to add some foam and see if i can get another 1 or 2. I think with more mass it would have been a little better, but for $1 worth of plastic im not complaining.
Of course now you can easily hear the vacuum itself, maybe a foam box…
dB are log, yes. 3dB cuts in half, 10dB cuts by 90%
you’re right, 3 not 10 
And it seems like just yesterday I was in high school physics 
But according to my phone app, I hit my reduction goal so I’ll take the A on the design and an F on the paper work.
