db6500 keeps blowing? please help!

[shawn earnheart]

i have db6500 components in my truck they are hooked up to a bridged alpine mrp-f240 amp (2x100 watt rms) and a kenwood exceleon x590 head unit.(22 watt rms - 4 volt signal). i bought these speakers used off ebay witch may be my problem,the left woofer voice coil went first so i called polk for a $60.00 replacement every thing was cool for 3 months now the right woofer is doing the same thing (plays at very low volumes, when i turn it up cuts all sound out briefly all this was proceeded by a burning electronics smell) my head unit has a built in crossover i'm keeping it up above 100hz on bass,mids and treble. also amp is in hipass mode 80hz cutoff. my gain is set at about 1/4 to 1/3 and i cant here any distortion. and i usally keep my head unit volume at 33 it goes from 0 to 35. i'm new to all this stuff any advise would be helpful just want to make sure i'm not doing anything wrong. would the mm6500's be more reliable?

[MacLeod]

If youre gain is set that low then chances are youre not overdriving them.

My first guess is simply that youre just the latest person to get screwed on Ebay.