So I'm finishing up the Studio Build and one of the things that was added to the list was trying to quiet the AC vent into the room. It is NOISY and in this small soundproof room, it was not very pleasant. The AC system is old, and seems to have two speeds, too low and too high.
The vent in question.
With the vent removed.
Hard to see but there is a flap up in there behind the sort of louvers that controls how much air can pass through the hold, this is the main source of noise as well as the white vent cover.
I want to kill the sound but retain the air flow, so my answer is to make the sound change directions but provide enough volume for the air flow to be not significantly reduced.
I had to make up the metal cylinder that attaches to the metal box in the ceiling, you can see the existing vent on the left and the piece I made to do the same job on the right, this just has the one flat panel that will go tight against the ceiling for now.
Here is the basic idea.....
The "W" shaped bit is the bottom the "U" shaped bit fits over it and has the inlet pipe in the middle of it.
Here it is together, it is upside down on the bench here.
The idea is that the sound will hit the middle of the W and go to each side, then it will hit the lip or outer edges of the W and again be forced to change direction. The inside of the unit will be covered with sound absorbing foam.
Here is the unit before it is put together.
Did it work...?
Yeah I think so, their is a noticeable reduction in noise, with my iPhone decibel measuring app on my iPhone from 1 meter away it was a steady 72 dB, after the install it has dropped to 59dB, that is a big difference.