I have a 2003 Subaru Forester 2.5 X with an Infinity Basslink subwoofer, a Kenwood KDC-X696 receiver, two 6.5 inch Kenwood KFC 1664S speakers in the front doors, two 5.5 inch Infinity Reference speakers in the rear doors (I don't have the model numbers), and an Alpine amp ( I don't have the model number either). I have had the Kenwood receiver in my care for 4.5 years, the Kenwood speakers for 18 months, and the subwoofer, Infinity speakers, and amp for about 11 years. A few months ago, I noticed a problem with my subwoofer. It started making thumping noises every 10 to 15 minutes. I discovered that the groundwire for the subwoofer was installed without the paint being removed from the body of the vehicle. I both removed the paint and cleaned the groundwire before reinstalling it. That appeared to solve the constant thump noise. I parked my car for 30 minutes and listened to music, but heard no thumping. I also connected my Samsung Galaxy S5 smartphone to the subwoofer using an RCA/headphone jack cable and listened to the subwoofer for about 30 minutes and noticed no thumping sound. The subwoofer works fine while driving, but I suspect that I am hearing a thump from it while driving on bumpy or uneven roads while listening to music through the in-dash unit and my smartphone. It is possible that I may be misinterpreting the bass because of my concentration on road traffic, I am sometimes hitting bumps or potholes during certain bass notes, or suffering ear fatigue from listening too hard for any other thumps from the subwoofer. I am moving out of my house in a couple of weeks to start school and I want to fix this problem before I head out. I am trying to see if I can fix the problem myself before shelling out the cash to have professionals check the stereo out. I have already ruled out the grounding and almost ruled out the subwoofer. Is my subwoofer, in-dash receiver, or RCA cable between the subwoofer and in-dash unit going bad? Could the Bluetooth signal between the stereo and my phone have anything to do with the possible thump? Can driving on certain road surfaces make sounds that are similar to a subwoofer thump, or am I just imagining things? Thanks in advance.
