You don't want the walls of the encloure to breath, that is flex in response subs back wave.
The flexing and or the back wave will distort the speaker response and makes tuning a challenge.
So many comp cars have 1" + wall thickness sub enlosures.
SPL guys even reinforce the hole vehicle with steel or concrete. I know 2 SQ guys using concrete to stiffen their sub box or panel around the box.
Anthony B. Davis
2Deep2 Silver SVT
2002 IASCA SQ Ult Ama 601+ World Champion runner up
2002 SLAP dBQ Champion
2000 USAC SQ World Champion
2002 USACi SQ World Champion
