Hey people..been floating around here for a while, but never had the reason to post. I have an issue with my rear deck db691's, (really just one). The speaker sounds blown, especially at low volume. Tried the 9v deflection test and it moves properly and it really seems like there is no scratching when the voice coil is moved. Could be me just not feeling it, but nothing adds up. I have a Pioneer Premier deck 50Wx4 which powers the 2 db691 rears and the 2 db651's in the doors. Also have a powered sub under the seat. Can't seem to definitively determine if it's blown or what the deal is. Does anyone know of a sure fire way to test these?? Also, are the 691's available as a single speaker through Polk? Maybe someone out there has one they'd sell?! Been screwing around with this stuff for years, but haven't had to deal with this type of issue before. Probably should read up on the overdriven / underdriven topic too I guess as this may be a cause of the failure, even though it really surprizes me that I'm having this problem. Any help, advice, or direction would be greatly appreciated. Thanks for the help.