Are you looking for pure spl or is this going to play music still? Cuase alot of ppl throw the word spl out there and there not realy going for spl. So unless this is going to be a burp box, dont call this an spl build. If this is for a loud DD i would do something like 1.5ft^3 tuned 40hz w/ 24in^2 of port and around 2500-3000rms.
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