As some of you know, I recently walled off my DC/AC closet, removed the DC filter on my Oneida cyclone, and re-routed the exhaust outside. That indeed lowered the noise level in the shop significantly, but I didn't realize how loud it would be outside at the exhaust port. As I am on 2 acres, it probably was not loud enough to trouble the neighbors, but I wanted to decrease that noise level as much as I could. In a different thread asking for advice, Rod Sheridan (Thanks Rod!!!) mentioned Oneida's silencers, specifically designed to do exactly what I was trying to do. I had no idea they made anything like this. I called Oneida and talked with one of their sales/CS guys who helped me locate the (7") silencer on their website. According to the website, this silencer will decrease the noise by 4 - 6 db. I asked the Oneida rep if a second silencer would further decrease the db level, and he replied by telling me that it would. So hoping for a 10 db attenuation, I bought 2.
I installed them both yesterday. As I cranked up the cyclone, I braced myself for disappointment. To my pleasant surprise, there is a HUGE difference. I don't have a way to quantify the result as I don't own a decibel meter, so my findings are strictly empirical. The volume dropped big time and what is left very easily sinks into the background as white noise at any significant distance from the port. A third might help even more, but it is not needed and I would think that at some point one would run into the law of diminishing returns.
I am extremely pleased with the result and would highly recommend this to those who are looking to decrease the noise level of their DC. The 7" Oneida silencer sells for approx. $125 if memory serves.
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