i have pioneer 6x9 3-way speakers in boxes in my rear deck, and a sony head unit. One day when i was listening, i noticed that i was not getting the same power that i had been getting. I was having to turn the volume up higher, but still not getting the same "thump" that i had before. I took the speakers out and made sure that they were wired correctly, but i can't understand what the problem is. Has anyone had this problem before?