I have a base R56 with a standard 6 speaker boost radio.

I replaced the front speakers and added tweeters.

Folks on this forum say that replacing the rears will not be a big improvement.

Do I have any existing wiring in the rear cubbys or under the seat to make for an easy subwoofer install?

Where and how do I tie into the woofer and/or amp into the existing the system?

I don't want a super upgrade. Something inexpensive and easy.

Thanks!

 

The problem with the rear speaker location in the R56 is that most of the rear outer panel's surface cannot be damped, resulting in strong mid-bass distortion at above medium sound levels as well as distortion of low-bass frequencies at any sound level. Hence speakers in the rear locations cannot be used for any significant bass output. At the same time mids and highs from the rear mess up the soundstage for front passengers (whether or not they are of any value to rear passengers I don't know).

Possible hidden amp locations are under the right hand side front seat or behind the left side trunk trim (where hifi and HK equipped cars have the stock amplifier placed). In the latter case you will also need the oem amplifier mounting plate as well as the trunk trim variant for amplifier equipped cars (the one your car most likely is equipped with does not leave any space behind it).

There is a wiring harness (X9331) behind the drivers left hand side footwell panel from where the speaker signal (high level) can be sourced. Note that on cars without a stock amplifier there is a 100Hz filter (notch) applied to the rear channel so using it as the subwoofer input channel is ruled out. Also, it makes things a bit more complicated if you also have stock PDC (rear parking sensors) as their signal is only output via the rear channel.

I posted pictures and information regarding amp location in the following thread if you want to have a look at it:
https://www.northamericanmotoring.co...ml#post4500270
There are also pictures of the amp location under the front right hand side seat.

Edit:
- Improved wording about bass distortion
- added signal source info
- mentioned 100Hz filter and PDC signal in rear channel
- corrections

 

Thanks so much! I'll look into your info.

So where would I tie into an input that I could use for a sub woofer?

 

Front channels (full range, high level)

 

Thanks again!

I misread your first post.

 

Ful range being the mid-range speaker?

 

The speakers in the front doors are hooked up in parallel. Hence they both receive the full range signal.

 

Makes sense and thank you!

 

Hi.
Just one question regarding wiring in the front doors.
I'm installing the 2way component speakers, powered by an amp.
I would like to avoid running new wires into the doors, as I heard it could be a little problematic because of the door harness. I would like to avoid reconnecting and drilling in it. Or ,maybe is not that complicated as they say in that case?
What I was thinking is that I will just connect the wires from the factory installation with a new wires going to the amp. It looks like the factory speaker installation has the wires good enough for running the external amp, and the distance from the speakers to the x9331 is not that long. So basically I want to leave the factory wires going from the doors to the x9331, and from this connector I will run a new wires to the amp.
Anyway, my question is : inside the doors the main wire is split to the 2 separate ones, for low and mid speakers. Which one should go the the crossover in such a case?
If they are split - will I get half of the power if I will use one connection? It sounds stupid, but it's better to ask just in case.

 

It makes no difference, as they carry the same signal.

No. If nothing is connected to the unused pair (nor are they shorted, of course!), then there is no current flowing through there and hence there's no power loss.

 

Thank you a lot

 

Just one more question :
If I will disconnect the speaker wires from the x9331 on the speakers side ( to joint them with the speaker wires to the external amp ) - will it make have any consequences for the car itself? I will leave the power wire and the ground in the plug.

Could you also please explain, why there is a power and ground in this plug? Where does it go to? I understand that there are speaker wires coming from the factory unit but power? What for and where does it go further in non amplified system?

many thanks

 

If you only touch the speaker wires, no consequences.

Note:

1. The car does sense whether there are speakers attached. Once you connect the wires to your high-level-in amp (or high-to-low level converter), the car will think that the respective channels are "open-circuit" (since the amp/converter will not draw any power from the stock radio). There will be no error message on the display itself, but if someone reads out errors with a BMW/MINI compatible code reader, there will be C540, C544 errors (for front channels). These error messages can safely be ignored, the radio will still provide the output signal to the amp and sound will play fine.

2. In case you intend to use an x9331 adapter harness (I made one with BMW parts, it saves one from working in that confined space and allows for a complete "return-to-stock"), make sure that the intermediate wires used for passing through the non-audio power wires are of adequate strength/diameter (they are thicker than the audio wires) and that they are crimped correctly and with fitting, proper crimping pliers to the pins. The same applies if you modify in any way or install any power wires (e.g. for your amp). The currents flowing through are significant. You want to avoid a situation as reported in this thread at all cost:
https://www.northamericanmotoring.co...ss-failed.html

I don't know why BMW chose to route power through there, you'd have to ask their engineers (I doubt you'll get any meaningful answer, though). Nor do I remember which devices are supplied with power via these wires. IIRC, none of the power wires is ground, though I'm not sure. I do remember that they are not there to supply power to factory fitted amplifiers.

 

Thank you big time. You couldn't be more helpful.