why do companys make these speakers. they fry amps I just purchased these from craigslist got them home and hooked them up to my sony STR d1090 receiver and after about 5 mins it started flashing protected and shut off, now even with other 8 ohm speakers it will go to protected as soon as you try to turn volume up. I have several receivers that are flashing protected from my bose 6.1 speakers that were 4 ohm now another one on the pile !!!! why do these companys make 4 0r 6 ohm? m