Just for (global) clarification - not in all markets - some have no amps in the trunk/boot (left cubby or under the spare) and all the speaker wires run up to the dash. Mine is like this.

But it seems all USA-market cars DO have some form of amp in the trunk - usually the BM54 receiver/amp under the spare and another amp in the left cubby (and/or the DSP amp).

Or so I hear/read/am told. ;)

Does a BM54 complicate upgrading? The dash din unit does have a power up option, like 0-5 setting. I have it on 4. The RR speaker tested 0 ohms. What DVM setting do I use to test wire output? Is the signal only up and down? I'll take a peak in the left cubby. I don't remember seeing a box there. It's mostly a big open space. The BM54 box looks big. The spare tire area doesn't have one that big.

I tore it out and replaced it all, so I’m not sure how the old amp plays with upgraded speakers.

Open the left trunk cubby and look down into the bowls of that opening. The non-dsp amp I had was a small unit (with an “Alpine” stamp on it) mounted to a metal bracket that seemed needlessly complicated, but I think was designed to mount additional options we didn’t buy the car with.
Pic from when I was mocking up my amp upgrade project but hadn’t removed the oe amp yet:
https://i.postimg.cc/2St5NZGG/PXL-20...3-Original.jpg

Blue arrow points to the bracket and I circled the top of the amp.


It’s a tiny box, maybe 5” x 5”, which likely accounted for the crappy power it put out.

Cut the mounting tabs off the replacement 6.5" drivers and they will drop right into the factory speaker door pods. To remove the factory 2ohm speakers you can use an exacto knife to cut the silicon adhesive that goes around the perimeter. I used 3M VHT to temporarily adhere my new drivers and then ran a bead of silicon around the perimeter as factory. Looks almost OEM. Like below:

https://www.caraudiojunkies.com/atta...3&d=1632763635

https://www.caraudiojunkies.com/atta...4&d=1632763635

https://www.caraudiojunkies.com/atta...5&d=1632763652

As others have mentioned, business audio (NA model) has an amp in the left hatch cubby. And 4ohm speakers will work fine in place of the 2ohm, but will be "underdriven." My wiring diagrams will do you no good as they are for DSP equipped X5's, but I could probably pull the business audio ones from TIS if you need them.

:wow: Sweet! I didn't think about cutting the speaker mounting ears. :bmw: Good to know a 6.5" will fit too.

While waiting for the A/C to cool down the inside, I took a peak at the rear cubby hole. I assume this module is a business AMP. If wiring colors do change from there to the speaker, it's going to get complicated. :( Continuity check to the speaker and power output.

I was hoping for a direct woofer swap. Now, I have to pinout the original connector and wire it back up.

If I understand correctly, this amp has to work correctly in order to replace the din module. Right?

Yep, that's the business audio amplifier with all the twisted pair speaker wires going into it. If you don't want to rewire everything to the new DIN unit, then yes, the amp has to be functional. I'll see if I can clip the business audio pinout diagram...

Dang those Kappa’s are mighty fine! :2thumbs:


E53 RiPPeR
XOuTPoST jUNkiE
ReVELaTiON 22:21

The speaker replacements are the hard part. As long as you are going that far, a new amp and head unit with RCA cables are just a bit farther to go! Use the OE speaker and trigger wires. OK... running the RCA cable is a bit of a pain too, but it will sound so much better than the OE amp.

A Dremel will work fine on the speaker ears, or a belt sander works great as well, which is what I used.

[QUOTE=Henn28;1240632]The speaker replacements are the hard part. As long as you are going that far, a new amp and head unit with RCA cables are just a bit farther to go! Use the OE speaker and trigger wires. OK... running the RCA cable is a bit of a pain too, but it will sound so much better than the OE amp.

This is what I have planned once I've upgraded my front speakers which are currently sat in a box waiting to be fitted , my question is do the speaker wires run from the doors to the rear and all the splitting and crossovers from factory are in the rear so I can just find the appropriate wires and connected direct to amps.

This is what I have planned once I've upgraded my front speakers which are currently sat in a box waiting to be fitted , my question is do the speaker wires run from the doors to the rear and all the splitting and crossovers from factory are in the rear so I can just find the appropriate wires and connected direct to amps.[/QUOTE]

I believe the crossover is done by the amp as I didn’t find any crossover boxes in my doors. You can definitely split the wires out of the connector, identify the various speaker wires, and hook the straight into a new amp. Identifying which wires go to which door/component can be confusing because the wires change colors somewhere in route to each location. Bentley gets you 90% of the way, and then I recommend using a AA battery at the amp end of the wires to check both the connection and polarity is correct at the speaker end. Label each one as you break them out of the plug.

https://i.postimg.cc/zX3LLC2n/PXL-20...8-Original.jpg

https://m.youtube.com/watch?v=pmU-Ky...F0dGVyeQ%3D%3D