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The speaker is not marked +/- and I am on the hunt for a 2019 wiring diagram. I have the 2018, but the wire colors don't match. I can figure it out by tracing the wires and x-referencing to the 2018 amp connections, but I made a separate post to see if anyone has it. As for the notch, it's to align the sub to make it easier to install. The corresponding tab on the enclosure can easily be cut off or obviated with a bit of foam tape when installing the replacement. The replacement need not have the notch.
Isnt there something about using a 9 volt battery on the terminal to check polarity when the cone moves forward. Can use that to figure out which wire should be positive and negative on the harness.
connect the positive on the speaker to the positive on the 9v batter, same for the negative. if the cone moves out you have it right. if the cone moves in you have it backwards.
I just ordered all of the parts. I'll have time to do the install in a few weeks. I'll update the thread with the results once I get everything installed.
I replaced the B&O and speakers/sub completely in my 2018 and taken the factory sub out; my assumption as far as what you want to do is that while the sub itself isn't top-notch it's not the weakest link in the chain either. Biggest culprit is the cheap plastic enclosure which, as someone already mentioned, flexes way too much for a sub box, followed by the weak amplification.
You could try stiffing the box with fiberglass spray as suggested, and maybe add some polyfill to increase the effective volume a bit, those are tried and true tricks, but in the end I'm guessing you won't notice much difference at all unless you also amp it better.
Still, credit to you for not only trying but doing your research and I hope it works out. At the very least it should give you confidence on what the next step should be.
I got around to gathering all of needed parts the past few weeks and replaced the factory sub today with the Rockford Fosgate 8" 4ohm DVC shallow mount sub. Installation was quite simple and for less than $200 in parts, is a nice upgrade. The sound difference is not night and day, as would be expected by replacing one 8" sub with another using the same amplification, but it is definitely noticeable in a good way. The bass is much tighter now. The factory amp has more than enough power to drive the Rockford 8" sub.
A few tips for those who might want to give it a try. There are no connectors available to mate with the factory sub connectors. I even contacted Digikey (with pictures provided) and they came up empty. So your choices are to cut the sub connectors off or tap into the wires. I opted to tap into the wires just in case I was not happy with the replacement and the results of my experiment. There are two pairs of speaker wires (one for each voice coil). There is a green/white pair and a red/black pair. I measured both and the white and black are the negative wires in each pair.
It was easier to remove the plastic sub box than to try to work with it in place. I'm glad I removed it. I was able to cover the entire box with Dynamat. I also noticed that the box was ported at the bottom, which was not obvious with it in place. The box is not nearly large enough to support the Rockford Fosgate sub with a ported install, but it is pretty close to the spec Rockford published for a sealed enclosure. So, I sealed the port. I also put some polyfill into the box.
The Rockford sub fits perfectly. There is a small alignment tab on the perimeter of the speaker opening on the box that is used to align with a notch the factory sub. That had to be cut off. Other than that and having to drill new holes for the Rockford screws (not surprisingly the stock speaker mounting holes do not align with the myriad mounting holes on the Rockford sub). Everything fit nicely, including the Rockford trim ring.
A few pictures of the box with and without the Rockford speaker are attached. In sum, I am pleased with the results of my experiment.
05-25-2019, 10:20 PM
