Duct Silencer: Measured Results

With an inexpensive decibel meter, a shop owner finds out how much a duct silencer has quieted down the noise from his dust collector cyclone. April 27, 2011

I posted in August about noise reduction to expect from duct silencers. As a result, I bought a silencer from Air Handling Systems and installed it between my outdoor cyclone and the indoor baghouse. It performs as expected and was well worth the cost. I should have done this years ago. Here are the results using a Radio Shack sound level meter on a weighting standing next to my return air baghouse in the building:
Before: 90 dB
After: 76 dB

Forum Responses
(Dust Collection Forum)
From contributor J:
I'm surprised you have that much noise with the cyclone outside. My cyclone is inside and it's usually louder than the machines I'm using. I've been thinking about building a sound reducing wall around the cyclone, but I may have to look into getting one of those silencers. Thanks for sharing your results.

From the original questioner:
The cyclone is actually quieter outside than it is inside. Most of the sound stays in the duct, I guess, and ends up back in the building.

From contributor O

I have the same experience; the noise is almost all in the ductwork, especially where it exhausts back into the room. I've been thinking of getting a silencer for my little 2HP cyclone. It's nice to hear that they can make a real difference.

From contributor C
Is that the less than $50 meter Radio Shack has on their online site? Seems like a good tool to have.

From the original questioner:
Yes, it is the one that is online (Digital-Display Sound-Level Meter, Model: 33-2055).