Fantech LD 8 Silencer, 8" Duct

I bought the 8 inch version and installed it myself. I had a run of 8 inch ductwork, cut out a section for this to fit - moved the pipe back to give me some room to work, then reconnected the cut ends with the fantech silencer in the middle, and secured with some hose clamps, and a clamp to a stud ( this is much heavier than normal ductwork ). It took less than an hour to install, and a lot of that was carrying tools up to the attic and back. The performance is great. Before I installed it, I got a fairly loud noise when running the inline blower, 65 db measured using an android phone app at high speed to 57 db after the silencer was installed. Low speed went from 55 decibels to 45 - so now it is extremely quiet at low speed.

My contractor initially installed this incorrectly, with the silencer between the fan and the roof vent. I measured the volume of the fan before and after correcting this, and found about a 75% reduction in the volume of the fan (FanTech only claims a 50% reduction). It is very easy to have a conversation even with the fan at full speed.

What Fan?