Sub and Amp Help!!!!!!?

I have two 12in Precision Power Subs in a Ported box, They are 2 Ohm rated at 300RMS 600Peak each. Each sub has its own terminal. I have them hooked up to a Kenwood Kac-8105D Class D Mono Amp. I twisted the positives from both subs together and vice versa and connected them to the amp. The subs only play at a very low rate regardless of the volume of the stereo. But if i mess around with the amp the subs just play extremely loud but not with the music, its just a straight flow of bass. Then other times it kind of burps every few seconds but won't play with the beat of the music. Anyone have any idea whats going on!?!? The amp is rated at 500Rms at 1x2ohms