PowerNaudio
10+ year member
the power of audio
i think its possible for your sub to have been bottoming out. since by you wiring the sub at 2ohms instead of the recommended 4ohms minimal load recommended for that amp. your amp was provably putting out slightly more then 500wrms when the volume was pushed, and that means your sub was being over powered and causing the sub to reach its mechanical limits and bottoming out. good thing the amp was able to handle the lower impedance load and not burn up like some other weaker amps.