red through the post some very helpfull infomation on it i have been reserching bit more aswell and from the knowlage i have gatherd i have designe a rectangle ported box
h14xd13xw17 using 3/4 mdf giving me volume of 1.29 vb
less the sub displacment 0.07 giving me 1.22 vb
tuned to 33 hertz wich is what i belive the type R tuning frequcny to be
using one 2.2inch round port calls for a leng of 5.68 inches
First go 1" MDF, any panel flex will hurt your score. Second, go at least 2cu.ft, while bigger isn't always better, 1.2cu.ft is pretty small. Third go a bigger port, 2.2" is pretty darn small, maybe some 4" like I went, 6" if you can wrangle it.
OK using 1" MDF, with outside dimensions used. 400mm height, 450mm wide, 500mm deep, single 4" port with length 300mm with 25mm flares on both ends, should give you 2cu.ft Vb, with a tuning frequency of 35hz.
ok went to the local car sterio installer who is very good at what he does
he told me to make
use n test all 4 boxs with different lenght ports with a 4 inch dia port
and try make the ports firing into the parcel sheld once i removed the infill panels and leave them blank directly firing them into the cabin