Thread: Exhaust position ,

Originally Posted by Shedguy

Just finishing off my dust extractor enclosure for sound proofing , using 30 mill chipboard for housing lined with 90 mill sound batts.. does it make any difference where I position the exhaust outlet to the outside of the shed ,on the side or top ?.constructing 2 metre box tube outlet lined with sound batts similar to main housing with finished inside size of 20 mill square ,will this be enough to deaden sound to outside of shed , cheers

The lower you can get the outlet to the ground the better as the sound has a chance of scattering of more objects just outside the enclosure than if its higher up as this can broadcast the noise all over the neighbourhood.

A straight box lined with foam is usually all that is needed. If you want to get fancy and have enough space an S or double S ben will be even better. The outlet needs to be large or it will add bCK pressure to at least 2x (preferably 4x) the cross sectionnal area of a 6" duct. Mine is a 1.5S bend 0.2 x 0.5 m or 0.1 m^2, a 6" duct is 0.0176m^2 so mine is 5.65x that of a 6" duct. I have an extremely sensitive pressure meter that enables me to measure the back pressure of this opening - it's <0.2% of the total DC pressure ie stuff all.

Thanks Bob , think I’ll increase exhaust to inside size to 30 cm square , cheers