Blower blade tip induced air turbulence is usually the dominant noise of a kitchen ventilation system. To reduce this noise, a silencer can be put into the duct path between the hood and the blower if there is room. The Fantech LD-10 is for 10-inch duct and is about 14 inches in diameter. You may wish to acquire Fantech duct clamps to make mounting easier.

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@kaseki, thank you! this is exactly the kind of information I needed!

I have that exact silencer.

Even though kaseki shared the drawings and the dimensions - this thing is huge. I mean it has to be if it is 10" in and 10" out but perhaps I didn't realize it. Plan for a LOT of space being needed.

(everything looks the same size on the computer screen....)

Indeed! Mine is in my attic. I have referred to this before, but in the attic if room allows, one can use a few gentle bends to fit stuff (like the silencer) and still place the roof cap or blower where it is best located, such as down-wind from any MUA intake. Hang from the rafters, not support from the floor joists for less noise transmitted to the household.

@just_janni and @kaseki thankfully there should be plenty of room and the attic, but I appreciate the warning about its size!