Questions about boxes

[RooTxBeeR]

K, 2 10" JBL GT1000D, My box is 2.5 Cu sealed. My question is, there any way to figure out mathmaticly without a actual hearing test, to see what a sealed box would be able to play audibly, like you can with a ported because of its preset tune port. I am mainly asking this, because the Owners manual says to make a sealed box for 1 of these subs at .74 Cu a piece, that means this box has enough room for 3 subs, but is housing 2. How does that effect from what the original one is, also when the suggested ported is to be 1.2 CU at 35 Hz tune port, and at 35 Hz port, when does bass get in-audible because the manual says 30-3500Hz range and if I can go lower I'd like to be able to hit down to low 30's. I did come to the conclusion that around 40Hz it gets to be the spot at which it gets in-audible. FYI who didnt see my last topic, my subs are inverted into this with 180* phase.

[bassl0va]

You need to use a program like bassbox or winISD to model the response. Also, the tuning of a ported doesn't make its response predictable without modeling it and adjusting the model for the environment it will be used in.

[RooTxBeeR]

Mmk well I will look into that shit