port calculation, gross box or minus the port itself?

[Alex JB 10+ year member]

I'm a bit confused, there's no surprise.

The port length calculation I used is this ((14630000*(D/2)*(D/2))/((Fb*Fb*Vb*1728)-(1463*(D/2))))

Sticky confirms gross volume is without port or subs volumen removed.

This is 2 x E8's, 0.6 cu ft each. for 30Hz = 4.5" dia port with something like 40" port length

That would be like tacking an extra 0.35 cu ft of folded port onto the 1.2 cu ft of box.

what do you think? 40" sounds a lot.

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[Alex JB 10+ year member]

Anyone?

I read loads on here and DIYMA about 12'16" per cu ft being a good rule of thumb, but is that gross or net?

even if it's gross volume, but 40" calc seem way too much port for a 1.7 cu ft gross box.