[Marty in NY]

Originally Posted by Go FasTA

One factor that might be in play is that the factory HK system has separate wiring for the tweeters and woofers, but both Bavsound and Focal use the woofer wiring and do not make use of the tweeter wiring. It makes me wonder if this could change the detected impedance values that BMW is checking against thresholds.

So what happens to the tweeter wiring? Does it just hang there as an open circuit? or do they give you a resistor or coil to plug into the connector?

For those who wanted to upgrade to Bavsound or Focal and are now wondering what's going on, the front door mounted tweeter just pops off using our hands and a bit of pull. You could pop one off, unplug it and go test the driver assist features. Don't know if only one door mounted tweeter would do the trick or if you would need to do both front doors. If the open circuit causes the issue, that would mean if you blow a tweeter, your drivers assist function wouldn't work. Id be shocked if this were the case but its a 10 min job to pull one.
Things that don't make sense raise my curiosity level even if I don't intend to upgrade my speakers

[Go FasTA]

Originally Posted by Marty in NY

So what happens to the tweeter wiring? Does it just hang there as an open circuit? or do they give you a resistor or coil to plug into the connector?

It just hangs free. If I recall correctly, the Bavsound tweeter plugs into the new woofer. The Focals include a crossover box that is wired to the factory woofer wiring as an input and has outputs for the new woofer and the tweeters. The Focals actually have two outputs for the tweeters: one at 0db and one at -3db. I’m currently wired to the -3db to tone down the highs a bit.

[mobilejo]

Most interesting thread this year.

Amazed and mind blown at the link between speaker impedence and AD functions.

Based on the series of events, I don't doubt that it is indeed the speakers causing the issue, but like others I would really love to know why they made it reliant on something like speaker impedance and without building in a warning message on the screen to tell you. As Marty in NY says, just blowing a speaker could throw off AD. That isn't a hard issue to fix, but without this thread it would have been impossible to diagnose! The car isn't telling you why AD isn't working and no one would have guessed it would be the speaker. In 3+ years when these things are out of warranty and some poor schlub who doesn't use forums can't get AD working on his new-to-him car, a blown tweeter will literally be driving someone insane.

[Go FasTA]

I dropped my car off 5 days ago due to malfunctioning AD and they called me that afternoon saying it was ready to pick up. They indicated they did a software update related to AD based on some fault codes and then drove it 5 miles during which AD performed flawlessly. As soon as I got the car I tried engaging AD and had the same “function not available” and “driver assistance malfunction” messages as before so I brought the car back in. This makes me wonder if the radio was off when the tech did his test drive which might prevent the impedance check from blocking AD. I’m getting my car back right now and will test this on the drive home.

[sk03]

My wild guess - low impedance speakers on the original amplifier might be causing two issues - a) mismatched amp/speaker impedance b) low impedance system can draw unpredictable current causing electrical system instability. Since sensors are highly sensitive to even a minor variation, it can jeopardize the AD function. Interesting is that even without the speaker system playing, is the amp snitching on the new speaker to the computer ?

[Go FasTA]

I had no luck on the drive home engaging AD with the radio off or on. Additionally, I couldn’t even engage distance control. Previously I could use distance control even when AD was malfunctioning.

[Go FasTA]

Update: I had an hour between meetings and was able to experiment.

1. Swapping the stock center channel back in while keeping the Focal subs and front door components installed did NOT allow me to engage AD.
2. Swapping the factory front door and center speakers back in DID allow me to use AD while keeping the Focal subs installed.


I need to correct an erroneous statement I made earlier in this thread: The stock HK tweeter just piggybacks off of the woofer just like the Bavsound setup. The wiring that goes unused is the run that goes from the stock woofer to the stock tweeter.

[Marty in NY]

Originally Posted by Go FasTA

Update: I had an hour between meetings and was able to experiment.

1. Swapping the stock center channel back in while keeping the Focal subs and front door components installed did NOT allow me to engage AD.
2. Swapping the factory front door and center speakers back in DID allow me to use AD while keeping the Focal subs installed.


I need to correct an erroneous statement I made earlier in this thread: The stock HK tweeter just piggybacks off of the woofer just like the Bavsound setup. The wiring that goes unused is the run that goes from the stock woofer to the stock tweeter.

For clarification on your #2. Does this mean that the front center and both front door woofers and front door tweeters were back to OEM and then the AD worked?

How about the rest of the speakers in your car, are they Focal or?

[Go FasTA]

Originally Posted by Marty in NY

For clarification on your #2. Does this mean that the front center and both front door woofers and front door tweeters were back to OEM and then the AD worked?

How about the rest of the speakers in your car, are they Focal or?

Correct. So my current set up is all factory stock speakers with the exception of the under seat subwoofers.

[Marty in NY]

Originally Posted by Go FasTA

Correct. So my current set up is all factory stock speakers with the exception of the under seat subwoofers.

Ok, thanks. If you still happen to have your, even just one, front tweeter housing apart, try to simply disconnect the tweeter connector and see if that alone kills the driving assist.

[Go FasTA]

Yeah I’ll tinker a little more when I have some time tonight or in the next few days.

[hmbmd116]

Originally Posted by Go FasTA

Correct. So my current set up is all factory stock speakers with the exception of the under seat subwoofers.

This parallels my findings. I have all stock speakers with the exception of the subwoofers, which are Bavsound subwoofers. I used the driver assistance plus today and can confirm when the camera in the dash detected I was not looking forward, I would hear a warning chime that came through the tweeters. It does seem that the driver assistance plus will not engage when the car senses there is no speaker available to give the warning chime.

[cellarrat]

Ha! If I had to choose between assisted driving and good sound I would take the latter without hesitation.

But it sucks (and is shocking) you can't have both

[Go FasTA]

Originally Posted by cellarrat

Ha! If I had to choose between assisted driving and good sound I would take the latter without hesitation.

But it sucks (and is shocking) you can't have both

It’s just a shame we can’t get B&W on the 50e in the US because I’d prefer to have both from the factory.

[SwissBeemer]

Originally Posted by Go FasTA

It’s just a shame we can’t get B&W on the 50e in the US because I’d prefer to have both from the factory.

I wonder if people are actually willing to shell out so much money for a bit of a better sound? B&W is available in Germany for the 50e and it was the only option out of the whole list that I didn't tick (and I spent 5k on individual paint ...) because it will cost you $4.5k. This makes it the most expensive option in the whole list, by far if we leave out individual paint which is not really a "regular option".

[mobilejo]

Would connecting some kind of resistor to the stock tweeter connector (to mimic the resistance of stock tweeter) fool the system perhaps?

Although if it did, would this mean that you wouldn't get the audible AD chimes?

[E91toG05]

This is indeed fascinating. I do wonder if the missing speaker is the issue - I get that the car will refuse to allow you to use the assisted driving if it is not satisfied that it can communicate to you via the audio system.

[Go FasTA]

Originally Posted by mobilejo

Would connecting some kind of resistor to the stock tweeter connector (to mimic the resistance of stock tweeter) fool the system perhaps?

Although if it did, would this mean that you wouldn't get the audible AD chimes?

I was incorrect earlier when I stated there were unused tweeter leads. In reality the stock tweeters connect to the stock woofers and do not have dedicated wiring direct from the amp. Thus, the system must be detecting the combined impedance from each woofer/tweeter combo and the aftermarket setups must be measuring below some unknown threshold. If the OP here does try the slightly higher ohm woofers that Bavsound offered him it might be a good test to see if those would be within the car’s nominal range and allow the AD system to activate.

[mobilejo]

Originally Posted by Go FasTA

I was incorrect earlier when I stated there were unused tweeter leads. In reality the stock tweeters connect to the stock woofers and do not have dedicated wiring direct from the amp. Thus, the system must be detecting the combined impedance from each woofer/tweeter combo and the aftermarket setups must be measuring below some unknown threshold. If the OP here does try the slightly higher ohm woofers that Bavsound offered him it might be a good test to see if those would be within the car’s nominal range and allow the AD system to activate.

Ah I see. Understood.

[Go FasTA]

There's obviously a lot more we need to learn about how BMW has chosen to implement this validation as a prerequisite to enabling AD. For instance:
- are they checking the aggregate impedance measured across the entire audio system?
- are they checking impedance for each speaker location?
- why do the subs not seem to have any impact?
- what is the nominal range in which the impedance must fall?

Hopefully some of the third party audio suppliers will do more scientific testing to help answer some of these questions and determine if they can develop upgrades that would fall within the expected range and allow the system to work or, perhaps, some kind of device or method to trick the system. For instance, if the car is checking aggregate resistance then maybe you could sacrifice the rear speakers in favor of a resister that would bring the total system impedance into an acceptable range...or replace them with higher ohm speakers that would offset the drop in resistance provided by the aftermarket speakers used elsewhere.

[Go FasTA]

Originally Posted by hmbmd116

I do have alternate midranges we can supply that will rest at a slightly higher impedance if you wanted to give those a go instead of just returning, if you would like to try that it would of course be free of charge.

I can't guarantee that will resolve anything with the active driving assistant, but if it truly is somehow related to the car sensing slightly different impedances to factory may resolve the issue.

--
Jeremy Whittle / BAVSOUND
Operations Manager / Head of Support

hmbmd116 are you going to try the alternate midranges they offered? That would be another interesting test.

[hmbmd116]

Originally Posted by Go FasTA

hmbmd116 are you going to try the alternate midranges they offered? That would be another interesting test.

I sent the speakers back to Bavsound for a refund, so unfortunately I cannot do that test.