Ok let´s see, you have a 1000 watts @ 1 ohm and 14.4 volts for a 500 watts sub, your voltage is dropping to around 12v because you have the stock ALT, you are seeing now 750 watts for example, your 10 hz frequency with a 60 hz tuned box is having a .5 rise as you said, now you have 600 watts, so, you have around 60% of the amp capacity if you are lucky, then, you go with another example, the AQ2200.1, you are only seeing around 1200 watts including impedance rise below tuning frequency and something like 1000 watts on the kind of music you mostly play for a sub with a STIFF as hell suspension and 3" coil wich can take around 1800 real watts without any problems, "it´s a joke" !!
If you prefer to buy a 1200 watts amp for a 1200 watts sub that can take way more than that it´s your problem, but don´t come here and try to say i´m all wrong just because i count on impedance rise BEFORE buying a new amplifier, instead of doing it after when i´m pissed off because my sub is barely moving, but what do i know? i only have 2 loud cars that can bass race over 150 dbs and make demos all day long without damaging anything, i ain´t wasting more time with you, i´ll stop watching this topic so i don´t have to read another respond from you questioning what i´m saying, i ain´t the most knowledged guy but i can asure you, i know some things.