dude when ur woofer is trying to flex out air and the air inside the box is trying to flex air the other way round then wat is going to happen?
i think many ppl go through this "out of phase" concept but never notice it. the burr burrr sound on low notes on many system is a pure expample of out of phase. there are many concepts
woofer which cant produce low end buckles on tones
woofer which can produce but give out of phase bass if box cant go low
loud volume without the sense of how much ur woofer can handle
remember heat is calulated as an average. if ur woofer can handle 600rms and u give it even 1500rms for 1 sec , its not going to blow. but playing it for a longer duration , will blow it.
u said ur box is tuned at 44hz...... so its very obvious it cant play down to 30 hz.... so naturally it going to blow. havnt u seen so many pioneer d2 blown up due to this reason? prefab box, trying to play low end bass....... poof* coil gone