Bad speaker ground/HU in protect mode

[ChrisPuh_Gone]

Ever since I got this 6th gen, the Alpine head unit it came with would (very) randomly find times to display "DC ERROR", and only the bass would play. I assumed something was bad within the radio itself because I couldn't find anything online at all about that issue, so I killed two birds with one stone and got a more powerful new Kenwood.
Now the Kenwood is going into PROTECT mode anytime, (as opposed to very randomly), the bass/volume goes up past a certain point? This eliminates the possibility of it being a head unit issue. Whenever I disconnect and reconnect my amp and hit reset on the Kenwood, the issue disappears and I'm able to bump again until the power hits that certain threshold, then it will go into PROTECT again. This all also happened when I removed my amp and subwoofer from the car in an attempt to troubleshoot.

If it helps, I noticed that whenever I turn it on while its in PROTECT mode, there's a quick "thud" that comes from the rear pass side speaker, but when I disconnect and reconnect the amp and reset to fix the PROTECT, that thud doesnt happen.

^after repeating this all to a local audiophile, we've come to the conclusion that my rear pass. side speaker is grounding out somewhere. After disconnecting that speaker and raising the volume on my system to ignorant levels, (both with and without the sub/amp combo attached), this was confirmed. Where exactly might that bad ground be? For reference, this is an entirely different harness than the one used on the Alpine but obviously the stock speaker wiring throughout the car is all the same. I read the 10 commandments of car audio in the FAQ and came across this:

V. Never use the ground wire in the vehicles OEM radio harness. This wire usually makes a very poor ground due to its length, small wire gauge, close proximity to other power wires, and unknown termination point. Instead, ground the source unit directly to the chassis or firewall.

^Could this be the answer to my issues? And if so, why is only the rear passenger side speaker being affected?

 

[Igor]

Locate bad speaker wires, check resistance open circuit, run new wire to the speaker if you couldn't find the problem. Little thin wire can be grounded easily by pushing it against the chassis. About the ground, yes it may be simpler to ground it to the chassis, but in all my experiences I never had an issue using car ground, unless something wrong with electrical system. Remember that now your ground or car frame receiving positive current from that speaker, so this may mess up other things

 

[ujinyuki]

try to put a wire from HU rear output going to your rear speakers. if all sounds normal then the culprit is the car's old speaker wires going to the rear speakers... hope this helps

 

[ChrisPuh_Gone]

Thank you both for your responses! Will go ahead and run a new wire since I have a bunch of spare 14 gauge laying around anyway.

Igor, I will definitely keep the part about the car's stock ground in mind

 

[danmccormick87]

try to put a wire from HU rear output going to your rear speakers. if all sounds normal then the culprit is the car's old speaker wires going to the rear speakers... hope this helps

x2! It'll also allow a cleaner signal and better response over the older, deteriorated factory lines! When in doubt finding a ground, run a new line! Trying to trace car electrical can be a PITA and if there is a simple fix, use that

 

[ChrisPuh_Gone]

Hey guys, so I ran a completely different wire from the HU's harness to that speaker, and somehow I'm STILL having the same problem! I cut and electric-taped the old +/- connections from the car, so what could be going on?

 

[Igor]

Hmm, DC Error means bad speaker connection. I would check all speaker wires for open circuit,resistance. Also double check the blue remote wire going into the amp.

 

[ChrisPuh_Gone]

Hmm, DC Error means bad speaker connection. I would check all speaker wires for open circuit,resistance. Also double check the blue remote wire going into the amp.

The older Alpine was showing DC Error and only playing bass but functioning normally, this newer Kenwood is just going into protect mode and not doing anything at all. Remote wire is fine, I checked that as well. How would I test for open circuit and resistance?

 

[lashlee]

The issue is in the speaker. The voice coil has heated up repeatedly over time and the epoxy that holds it tight is beginning to fail allowing the wire to uncoil and as you increase the volume it moves and eventually shorts out. Replace the rear speakers (I would recommend the pair) and everything will be fine. If you hook up a meter to the speaker it will show somewhere around 4.6 ohms but should go to 0 at some point if you move the cone by hand.

 

[Igor]

Use something like this

And if everything works fine, after disconnecting that speaker, ^member here pin pointed your problem