Box depth for a TC Sounds LMS Ultra 5400 18"

[Inertia]

I am going to purchase 2 of these subs. My question is... whats the smallest dimension for proper air flow to the back of the sub? The sub is 11.54" deep. So would a box that is 1 inch deeper than this be enough room for the sub to breathe? Thnak you!

 

[avengineer]

I am going to purchase 2 of these subs. My question is... whats the smallest dimension for proper air flow to the back of the sub? The sub is 11.54" deep. So would a box that is 1 inch deeper than this be enough room for the sub to breathe? Thnak you!

Box depth is not really the important figure, but you're not giving enough information about the box design for anyone to even guess.

Is the box sealed or ported?
What are the other dimensions (if known)?
Are you familiar with the Thiele-Small parameters and how to use them with subwoofer design software?

 

[Inertia]

Sorry I didnt provide all the info... The box will be sealed.. 20" x 19" x 14". On WINisd it said 2.25ft3 would be the ideal enclosure with a Qtc of .71... Im wondering if the box was 12.5" deep would the back of the sub have enough space behind it to properly cool? The sub is 11.5" deep so the back of the sub would be an inch away from the back of the box.