I was in the process of upgrading my front woofers and think I might have blown a channel while testing the new speaker ( ). The polarity was incorrect, but just for a moment, now I can't get any sound to come from any speaker I connect, including the old factory one. The other door speakers work as they should. It seems weird that reversed polarity would have this effect, but I realize these are sensitive cars.

I have an unlabeled stock system from 2011. I'm not sure if that means it's B&W or if that was a factory upgrade and I have a "base" stereo?

Either way - should I try to find a factory amp or replace it with an aftermarket one (if so, tips appreciated!), or is there another test/fix I should try before replacement?

Thanks in advance!

EDIT: My battery was low during this process. It was at the dealer last night and it wouldn't start when I went to pick it up this morning (not sure why, they likely left something open/on overnight). I drove for about 30 minutes but that may not have been enough. The car shut down while testing the speaker and I had to recharge the battery to start it. This may be an important detail.

 

I'm still learning to drive my car and haven't even thought about upgrading the stereo. That being said, I have upgraded several past cars. I've never had a problem with going up in ohms. These are different though. Chips instead of transistors, it may have damaged the system. My other modern car is very sensitive to a low battery. Varied intermittent failures will happen. I would probably get that sorted first then circle back to the stereo.
Just listen to big band and swing music until then. Benny Goodman doesn't use a lot of base.

 

I have replaced the power output chip in a few of the modern car radios, amplifiers and head units.
It's not rocket science but does require soldering experience and skills. The chip is normally a multi pin device mounted on a heatsink.
Best take your unit to someone who knows what to do or replace the amp with the same unit. Car parts recyclers don't charge much for them or try ebay.

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Thanks. Do you think the fact that I was using a 4ohm speaker instead of a 2ohm one is what caused the damage? I'm trying to decide whether to continue with this speaker install or source 2ohm speakers instead.

 

The ohms difference should not have killed a channel. You went up in resistance not down. Going down can kill one but going up only makes the music quieter. You should never mess with something like that with power on. I don't know how many people have burned out a channel on home stereos when messing with speaker wires with power on.They accidentally touch the wires together and short the output. That will kill a channel instantly.

The inputs on a speaker are isolated from the metal basket to keep you from shorting the positive to ground if you hook it up backwards. That is not a problem either. It only affects the perceived sound because it will be out of phase. As one speaker goes out the other will go in. You must have touched power to ground at some point. The only other possibility is static electricity, chips are much more sensitive to the static charge on the human body. Under an electron microscope you will see a static charge strike as a bomb crater in the substrate. As the substrate has gotten smaller the damage becomes more important.

You may have destroyed an output chip, it happens everyday, but I would make sure I killed it before spending money for no reason. Another consideration is that manufacturers have gotten more sophisticated with car stereos. On my other car you have to have a dealer reprogram the radio with a new vin before it will work in a different car. Since people said the key fob can't be reprogrammed to work with a new car unless it is divorced from the car it's programmed for first. The radio may be the same way, most times a junkyard just takes a part off and puts it on a shelf. A lot of times they can't power up a car to "divorce" any of the parts. Something to consider.

You also need to make sure no bare metal can touch the car body when the speaker is installed. If the positive wire touches ground you can instantly fry the output on that channel. So you have to clearance the positive connection or insulate it completely. If you have heat shrink you can insulate with that.

 

Rhomanski has nailed the possible reason for amplifier channel failure with a very detailed post. It's quite unlikely that the higher speaker impedance caused the failure because you would have presented less load on the output than normal. These OEM amplifiers are usually very basic with no protection for the driver chips other than the 12V supply fuse.
Only if the amplifier is a separate module to the radio unit will you be able to replace it without dealer intervention.
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Thank you for the detailed response. Note to self - don't try to do this stuff when you're both tired and in a hurry.

The wire I was using for testing slipped out of place with the sound on, I'm guessing that's what caused the damage. It was either that or the low power situation. I've charged the battery since and am going to attempt to source an OEM female plug so that future connections will be far more secure. I'll take your advice on the heat shrink, as well - good thought.

How would I go about finding out if it's dead or not?

EDIT: Both the sub and midrange door speakers are out, the tweeter still works.

 

Try it with the engine running and a good connection. If it doesn't work then, it's probably blown. It probably shorted with the dodgey connection. Sorry to tell you.

I just bought the service manual, I'll see what I can find.

 

I've tried, it's dead. I found a replacement on ebay for $195, so not too bad. It seems easy enough to access through the trunk, fingers crossed it'll plug & play.

 

There's three different systems for the 2011. A 400 watt system with 12 speakers, a 600 watt system with 14 speakers and the 1200 watt Bowers and Wilkens surround sound with 20 speakers. So, counting the speakers will tell you which system you have. The Bowers and Wilkens will have a little plaque on the wood trim on each door right beside the speaker, you can't miss it.

I'm not used to British manuals kinda reminds me of searching an airbus manual, but it looks like there is a separate amplifier module and it appears to be mounted on the left hand side of the trunk. It says to find a loadspace trim panel lh article. So I would say you need to take the panel off the side of the trunk on the left side to access it. Looks like it has four screws and six connectors and maybe a huge price tag. It's apparently connected to an optic fiber network. Which are fairly expensive to work on. Be very careful with the connector for the fiber optics. The only fiber optics I've worked on was on the Boeing 777. They were just starting to come in when I retired.

Okay not too pricey. just make sure you get the right one. They should be a little different for each system. One should be 400, another 600 and the Bowers and Wilkens 1200 watt. Good luck.

 

Thanks - you've been a huge help!

I was able to match the part numbers, so assuming the amp I bought is functioning properly, it should work. It's easy to access, so I guess it's just a matter of being (very) careful with the connections and ensuring nothing is powered on this time.

 

One last thing, disconnect the battery before you install the new amp. You could wrap the positive cable end in a piece of printer paper a couple layers thick and tape it on. That will keep it from reconnecting on it's own while your working in there.

 

I have same base stereo in my 2011 XJ. What are upgrade options for this system? Is it possible to make sound better installing different speakers? As im planning to do car sound deadening, i would consider upgrading sound as well.

 

I've learned a few things in the past few days:

1. These cars are super sensitive and working on the stereo is more like servicing a laptop than a typical car audio setup.
2. The factory system is proprietary and delicately balanced. The woofers in the doors are 3ohm (not 2ohm, as I'd previously thought) making direct aftermarket replacements impossible to source.
3. Retrofitting an aftermarket to replace the amp the factory amp is so difficult it's not really worth it. You can add an amp for subs in the trunk (using a lineout converter) but that's about it. I'd love to be wrong about this, but suspect I'm not.

Since I've already blown a channel, so have to replace my current amp, I'm going to test the 8" woofers I bought in the driver's side door to see how they sound. If they're good, I'll post here to let you know. I will be adding sound deadening either way.

 

What ended up happening with the speaker swap?

 

I pushed in the little dome on the back of the door speaker, put everything back together, and it mysteriously works just fine now. If anyone needs an amp, I have an extra.

 

That is so weird. That dome should just be a dust cover for the voice coil. I've fixed a few speakers Never heard of anything like that. It is English, so it's got to be weird, Usually you have to replace the whole cone assembly to fix a buzz. Why it made the whole channel go out, I'd have to tear it apart to figure that out.

 

These speakers are a bizarre design and when the cone is popped out or the surround is failing the metal coil barely touches the magnet and it causes distortion sounding like a blown woofer. But it's not blown. Similar sound to if the + - wires were barely touching. My driver door was like this and it kept getting worse. If you pull on the Orange surround you'll see it's starting separate from the frame so the issue starts happening. Anyways I swapped all the door woofers and the car sounds amazing. Had to basterdize the old speakers to use as mounts, but they worked perfectly, not one rattle.

The. I couldn't get to the rear deck woofers so I re-glued the surround with speaker surround epoxy and they sound great again too. I had the bowers Wilkins set up.

 

Crutchfields in Virginia sells that adapter ring. You mount the new speaker to it and then bolt the ring in like the original speaker. I've always used the Infinity Kappa series speakers in all my GM's. So far the B&W speakers are ok in mine.

 

I had already started and I was impatient so I just made my own. I cleaned them up with a grinder and added some polytape to make a seal and they worked perfectly. Plus they were free :-)