I think I want to build a TH for bass, Cubo Sub or similar

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For example: if I have an enclosure dimension of 12" cubed and a port with unknown dimensions, I would have 1 cu. ft. of volume minus the volume of the air contained in the port?[/B]

No, if you have 1ft^3 of air volume in a box and you put a port into that space you have to subtract the volume of air in the port and the volume taken up by the wood the port is constructed of.

I'll model the box you are considering if you can give me exact dimensions and tuning wanted.

note: The HP filter will rase the group delay as much or more than the port itself will.
 
I think I'm going to put two Peerless 830500 drivers in a roughly 21" cube ported subwoofer. A Thor subwoofer should be that large anyway. The ports will be slotted MDF ports wrapping around four sides of the enclose (1x18 inches) with a ~2.39" (might have to be a little bigger) radius hole at the top going from the enclosure out, exiting on the bottom out of a ~2.39" (I might make it much larger) radius hole. Both holes will have 1.5" radius chamfers. The bottom will have tear drops with the point of the tear facing the port so to keep the area of the port roughly the same as it flows from under the subwoofer (the subwoofer will sit right on the ground). The two remaining sides will have the woofers on them. I'm not sure any one can picture this. Also I'm not sure why I've never seen an enclosure made like this. Seems hella elegant and sh1t as they say in LA :drool:

can you do a sketch of this? from the description you may be doing many things... iffy. The maximum ratio of a slot port should not exceed 1:8. 1:18 would suffer from port compression at low levels.

a drawing would help a lot.
 
Yes, I forgot about port compression because of the 1:18 port ratio. I've changed my enclosure plan, since then. It's going to take me awhile to design and build this subwoofer, sometimes it takes me years. It's kind of off and on for me. Right now I think I'm going to build a ported box with a long slotted port with 2 bends, but after it's built I might or might not use the port. I always figure: build a ported box, so I can use it as ported or sealed.

MJK worksheets assume the port is outside of the dimensions that are specified for the box in the worksheet: http://www.diyaudio.com/forums/full-range/145846-mjk-worksheets-7.html

HP pass filters raise group delay? This would only apply when using electrical circuits in an amp, no? I'm using kx drivers on my computer as a crossover and 7/8 channels of amplification.
 
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