Plans for a straight Voight Pipe for the EV 12trxb, or SP12B drivers.

The vent could be larger and vented out the back of the cabinet for a greater bass emphasis.  Stuffing will alter the way the cabinet enhances bass.  All measurements are in inches by decimel ( 12.25 is 12 1/2").
A good alternative port design would be a exponential slot 22" long, vented out the bottom of the back of the speakers, remember the narrow end of the slot goes toward the driver.   For maximum bass vent straight out the bottom with the cabinet on stilts at the corners, adjusting the height of the stilts would control the amount of bass enhancement.  The curved pieces are not neccessary, as the the standing wave is excited down the middle of the cabinet, but this would help prevent other standing waves, making for a less peaky bass response.   The internal baffle in the middle could be a little longer, or the over all height of the cabinet could be shorter.  This is just a basis for variations you could use.
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