When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I'll tell you how I tested mine...I installed Power Effects. 1) it wasn't louder. 2) open vs closed made no difference. Therfore, I conclude my cat was clogged! Not exactly the cheapest way, but it works!! ;)