The thing that I like about round/flared ports is the tunability after the fact. I can actually run different length ports for daily and for SPL (to a point that is).

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I like my gear to be loud and clear.

OK, my $.02
Rectangle vs round, little if any difference.
Flaring/routering the openings can have a slight difference (usually a very subtle difference in depth.

But I was convinced a slot port is actually more of a hole cut in the enclosure with no porting at all (similar to a bass guitar cabinet). This is what I am using for my (2) 24" subs. I ran several examples, scenerios, and hole sizes using Bassbox pro. So far the preliminary tests (running VERY long speaker wires from my home sub amp) sound pretty darn good.

slot port is just a hole cut in the box??????? :P

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2002 Pontiac Grand Prix GT (Sedan)
Alpine CDA-7995 HU
Alpine MRP-F250 4chan amp
Zenon 2200w/1ohm mono amp
12" Rockford Fosgate T2 sub

a slot port is just a hole in the box.........

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Premier 980BT
(2) JBL 660gti
1 JBL GTO 75.411
2 SSA Icon 10"
1 Crown BPX 2200.1
and a bunch of other crap stuffed into a Tempo

"CAPTAIN TEMPO"

Sure. Its also known as an "open back" cabinet. They are very common with commercial sound (you know like concerts?) I realize we are not discussing pro-sound, but many car audio subwoofers can be used in infinite baffle situations
As a driver's T/S specs start approaching spec to be considered an infinite baffle, the cabinet can be tuned with a simple "hole" in the back of the box. Hence it would be called a "slot".
Whether a tube is round, rectangular, or square, it is still a tube. C'mon you have heard of "insert tab A into slot B"? I guess it is a question of semantics.

The next time you are using a port calculator and the port length is going to be way too long, try using the length of the port at .75" (or what ever the thickness of wood you are using). You may be suprised at the results.

As I posted way back when... a flanged or aero port will behave more like it's actual length, and a regular port will behave as if it is a bit longer then it really is...



If you are using a program like WINISD to design your box, you can enter a port coefficient... for a regular port it is 0.614 and should always be consistant...

for one flarred end it's .732 and if both endes are flarred it's .850
Of course these coeffiecients depend on how deep and aggressive the flare is, so they are ballpark figures only...





If you are building a box using slot ports that share walls with the box (that extend far beyond the port wall) the end corrections are also different.... for a regular slot port sharring three walls like I would normally build it's 2.23...

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SIC Audio