Wall Vent Sound Maze (Low Flow)

This was a fun little project that I just kind of stumbled into and figure a few other people might find use in this.

Updated Higher Flow Baffle Design is here.

• What and Why
  • Have a whole house fan and wanted to be able to install vents for each room so I could still run it if the doors to the rooms were closed.
  • The stock insert that came with the pathways was okay at keeping light out but that was about it.  It actually seemed louder out side the room with it installed and it was (see table below with all testing).
  • Was looking at some out proofing and came across sound mazes and saw that some people at used very large gyroid infills to make panels to trap noise and wondered about combining the 2. 
• Results
  • Available vent sizes
    • 14x8 Return (https://store.quietcoolsystems.com/collections/zone-air-pathway/products/zap-zoned-air-pathway)
  • Material
    • I used PETG for this but I'm not sure it really matters as there is no really stress and pla would probably print better.
  • Logic I went with for this config, but have not idea if I'm correct on this, other than it seems to be working.
    • 
  • Tested a few different configurations with my phone and a sound meter app to get an average over about 30secs.
    • I played Shakira, Ed Sheeran, Beéle - Hips Don't Lie (Anniversary Version) on loop for this testing because that was the first thing i saw when I opened my player lol. https://www.youtube.com/watch?v=41ZY18JqI2A
    • I set the receiver to -33db for all tests.
    • Results table

      • Room Door:	Location:	db
        Open	1ft in front of receiver:	54
        Open	Outside door:	45
        Closed	Outside door:	36
        Closed	Infront of vent (no stock insert):	40.5
        Closed	Infront of vent (stock insert):	38.5
        Closed	Infront of vent (foam lined only):	38.5
        Closed	Infront of vent (Sound Maze 35% infill):	35
        Closed	Infront of vent (Sound Maze 15% infill Optimized orientations):	31

  • My testing showed it was about 2db louder outside the vent than the closed door.
  • My last maze got down to 4db less out side the vent than the door, which is a win for me because the door is the same week point as before the vent was put in. 
  • I did do some flow testing on this and found it to be a very large reduction in airflow.  Only only recommend this version if you are looking for something to just allow 2 rooms to equalize with a lot of airflow and are mostly interested in sound dampening. 

    • Reduction from Full Open	85%
      Reduction from Cardboard insert	71%

• Process
  • I started by removing the insert and lining the vent with this foam, I imagine a similar foam would also work. 
    • This is the junk insert I removed
      • 
  • I crated the maze based on the max sizes for the printer and created modifier bodies to remove the walls in some areas to help better trap the sound.
    • 
  • After printing I lined the outside of the outer U with foam and the long leg on the inner T shown below.  Basically the idea was to let it always have foam on 1 side.  The ends don't need it because they back up against the foam lined passage.
    • 
  • I don't have a picture of it, but the spacer that is printed just goes around the inner T where the foam wraps around to hold the U open when you slide everything in.
    • 
  • Put the cover back on and you are done. 
  • If you find it is rattling a little you can use some of the foam to pad it in places as needed.
• Modifications.
  • Depending on your vent size you might need to adjust the sizing to fit.  Happy to make different sizes if needed.