Center T-Slot Port Question

[St33ler_in_Oz]

NOOB to ported enclosure designs!  (4) SA-6.5s in a center T-Slot box design, 2 drivers per "chamber", each chamber is .7 cubes.  Does the T-slot create 2 "chambers" or do the driver share the 1.4 cubes?

[Joe X]

It's like two different enclosures sharing the port, since the port is being shared it needs a port area 4 times as large as 1 sub would need. So if 1 sub needs 4.5 square inches, the shared port enclosure would need 18 square inches. Since the chambers are not shared each chamber is twice the volume as one sub would need.

 

[St33ler_in_Oz]

Thanks Joe X!  So I'm designing in WinISD.  Again, box for 4 drivers @ 1.4 cubes tuned to 50Hz simple cuz the vent length below 50 is INSANE and unpractical and I plan to have (2) 12s driving the low-low end.  Vent area is 42sqin (6x7) @ 26.8in long.  Main center port is basically 11in long @ 6x7, then T's off the remaining 15.8 to each chamber @ 21sqin (3x7).  Am I on the right track?  I'm anal about aesthetics, thus the center T-slot design.  What's making me question my plan is when I put 2 drivers in WinISD @ .7cubes to 50Hz (each "chamber" in my 4-shared design), the port length is DOUBLE at almost 60 INCHES LONG!

[Joe X]

The port area you are planning on is too large and that is the reason you are getting such a long port, you need 4 to 4.5 square inches of port area per sub, WinISD should be able to show low port speed, tuning needs to be lower subs cover 20-55Hz range in most systems, for these small subs, you should tune 38-40Hz but not higher.