deltalite 2512 cab designs.

[Triad]

I love how it looks!

 

[billfitzmaurice]

What defines "very narrow" in a shelf port?

Less than two inches. There's friction of the air mass against the duct wall within about 1/4" of the duct wall. If that friction zone is a significant portion of the overall duct area a lower Fb will result. The duct location has little to do with it. Narrow ducts tend to be located at the edge of the baffle, so the result of the narrow cross-section can easily be mistakenly attributed to the duct location.

I'd be interested in knowing what difference corner ports (two walls) vs. mid baffle triangular ports (one wall) would have in calculating post length...

None IME.

 

[will33]

So the 1/4" friction doesn't happen as much in pipes and triangles because the area is more evenly distributed?, ie: not a really long side less than 2" the air has to kind of "squeeze through"? Assuming sufficient port area in the first place, etc.

For whatever reason, the shelfs prove to be too long in several peoples builds, I think going back to some of the first fearful stuff. I just don't get the why. Figured maybe some error in the modeling program. Walls adding to effective port length, etc.

Whatever it is is off far enough to cause headaches. One I just patched it all in and stuck pipes in it. Another I started with the shelf obviously too short and added length a little at a time.