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http://www.audiobahninc.com/tech/Calcul ... o_Slot.htm

Yet another useless rendition brought to you by your pals from Audiobahn Incorporated!

Ok...so what is that calculator saying? Make ur round port box into a slot port box?

Thats how i interpreted it.......

TEDD

It calculates the surface area of a circle by using its diameter.

Can you say "pie R squared"?

nist7 wrote:It calculates the surface area of a circle by using its diameter.

Can you say "pie R squared"?

No, but I can say "pi R squared"

Is a circle port very common in the audio industry anyway?

Not really circle, but cylindrical ports. They are most common on prefab boxes.

The only round ports Id use are precision aero ports. Other than that slot ported is the way to go IMO.

Round ports are nice when you are short on space, but yeah, most perfer slot ports. Really though, both have their advantages and disadvantages, both work well if done right.

I thought a "slot" port and a "rectangular" port were two different beasts with a slot port using an enclosure wall at one or more sides of its internal termination. Because more air is forced to vibrate along with the rest of the collumn of air the effective mass is increased resulting in a slightly lower tuning frequency as a regular rectangular jobby of equal length.

Here's a much better calculator that does both types:

http://www.carstereo.com/help/Articles.cfm?id=31

JL Audio refers to them as "slot ports" in some of their driver specific recommended enclosures sizes:

http://www.jlaudio.com/subwoofers/pdfs/W6v2_MAN.pdf

and as "ducts" in one of their tutorials:

http://www.jlaudio.com/tutorials/ports/index.html

The inconsistent nomenclature sure had me confused for a while and I'm still not sure I got it right. Maybe all ducted ports can be considered "slotted" but not all slot ports are ducts.



-Fishy

A slot port and a duct port are generally considered the same. Where you might be getting confused is Slot loading, which is the act of firing the woofer side of a sealed enclosure into a 3-sided slot to gain SPL. this is how most Q-Logic Q-Customs are loaded. they down fire into the floor and the 3 sides around the woofer force the air moved by the woofer out the slot, in most cases resulting in a 3-db gain vs. an otherwise unobstructed path.