I have an Alpine 9805, 50 watts x 4, and I just got two pairs of Polk DB350s to replace my stock speakers.
They sound GREAT, but when the volume gets up a bit (not too loud, actually), they'll pop when there's a bass hit or sound hit (e.g., Counting Crows Elizabeth song from Recovering the Satellites--not a huge sonically stressing song). It seems from research that they're bottoming out. Is my solution to get blocking resistors and put them inline? Where can I get them? My two usual sources are Circuit City and Tweeter (nee Bryn Mawr Stereo).