i plan on making a sealed box but i want it to be alot bigger than it supposed to be. wouldn't that make my subs louder and deeper. i don't know i was just wondering cause my friend has a huge sealed box for his 2 12" mtx subs and he is setting off everybody's alarms from far away.
A larger sealed enclosure would be louder, but it would sacrifice low end and would respond as fast. Basically, it would ruin what a sealed enclosure should be. For your application, a ported enclosure would be a much better idea.
larger sealed boxes actually produce lower notes more effeciently but they produce higher notes less efficently(your low end will be louder in a large sealed box). Also in a larger sealed box it can be easier to bottom out your sub.
Yup, a large inclosure makes it easier to bottom out, overextend, too much excursion... well, its not good. You can actually blow a sub easier in a large box. A sub in a large inclosure doesn't need as much power to reach full excursion, but in a small inclosure, you can put more to the sub.