Basic 'Hifi Speaker System' Upgrade

[B21]

I can confirm the rear speakers, at a minimum, are going to be an absolute pain in the arse to fit

There isn’t much room at all to use an adapter, I’ve modified one and printed this afternoon, so I can make the speakers fit, but no way at all the grill would then fit over them. Need to do some good thinking about how to tackle it without making an ugly mess.

I’ve not even taken the door cards off yet to see what nightmare I face there.

The subs are more tricky best solution imho is standard bmw enclosure and bmw specfic subs be they OE are other factory compatible of which there are many all be it more expensive…but much better..

There are more options on the 100mm ..biggest issue is having to drill a hole in the back of the splash guard to accommodate the much bigger magnets or better quality speakers..

 

[TBDL]

Subs may come in future, we'll see how it sounds when the mids are in. It's not even a daily driver, but in a way that's even more reason to have perfect sound when I do get to drive the Z4!

For today, rear speaker were the distraction. Progress so far as follows...

Modified a 3D file off Thingiverse, modified it in Tinkercad, to better suit the fitment on the E89 as a speaker adapter from three to four hole mounting. Badly modified as my patience and 3D modelling skills are both low, it'll do the job for me though. May tinker more tomorrow if I have time and do a V3. Final prints are these:



The adapters take the speaker nicely like this, the yellow circles bolts being the ones that go into the original car mounting holes, the orange circled ones just fit the other two speaker mounting points to the adapter. As such the speaker takes two bolts into original holes, they seem to hold it well enough. It's not a perfect fit in the E89 recess, but it'll do for me as it should not be seen behind the grill. I have black M5 bolts coming tomorrow, these silver ones are just what I had to hand for a test fit:



I needed a bit more room behind the grill for the speaker, for now I have snipped some of the plastic off the trim. The metal mesh sits very tightly against the tweeter, but I think will be OK. I have ordered some speaker material to replace the metal mesh, as a plan B, in case the trim keeps popping off due to the pressure of pushing on the tweeter. Material will obviously be far more flexible so should suit the job fine if I need it:



I almost spliced the wires, but decided to be patient as I have speaker cable adapters arriving on Friday (Ali Express) so I can clip them straight into these blue factory ones:

 

[TBDL]

Ali Express adapters make the speaker wiring job easier. I wouldn’t historically have bothered, quite happy to solder, but I like these:



Overall fitment is OK, not too pretty, not too ugly. Mesh grills are a bit tight though so I’m going to try material ones:

 

[TBDL]

Front speakers installed, thankfully the door cards are forgiving enough to take the extra depth required by the printed adapter. The adapter needs to be as deep as it is to fit the larger magnets in the door recess.

It was actually a relatively easy job to do all four speakers, I just need to locate my hot glue gun to help the rear speaker grills stay in place with a little glue in the tabs.

I did break a speaker wire connector off in the factory speaker, so ended up soldering on one of the wire pairs.

Front doors (grill is on too, just didn’t take a photo):


Speaker adapter I printed, worked perfectly:


What not to do with the connectors:

 

[TBDL]

This is what I’ve attempted to do with the rear grills, used speaker fabric instead of the metal. Covered the whole insert panel for ease. Just needs sticking in a little better as it’s popping out as the lefthand side. I’ll use a bit more black hot glue then trim off any glue that can be seen when set. I’m using hot glue as it’s easy enough to then remove when needed, I don’t want anything permanent like superglue as that will be a nightmare if I need to get them off in future.