[esaru]

Originally Posted by Billfitz

6dB filtering is inadequate. It's what the stock BMW arrangement uses and is one of its major shortcomings. I designed my own crossover. I posted this a few years ago:

The original OEM setup doesn’t have crossovers between the midranges and tweeters. It only has a cheap NPE capacitor that keeps the midrange out of the tweeters. It doesn’t do a very good job of it, leading to distortion. There’s no filtering on the midranges to keep the high frequencies out of them, so literally a quarter of the high frequencies are lost going to the midranges that can't reproduce them.

This third order high pass filter is sixteen times more effective than a single capacitor in blocking midrange from the tweeters.



The low pass filter is second order. By using a third order high pass with a second order low pass polarity issues are avoided.



These are the parts:

8.2uf cap: https://www.parts-express.com/Dayton...acitor-027-426

20uF cap: https://www.parts-express.com/Dayton...acitor-027-436

0.1mH coil: https://www.parts-express.com/Dayton...r-Coil-257-020

0.2mH coil: https://www.parts-express.com/Dayton...r-Coil-257-024

These filters tap into the wiring to the drivers. The tweeters normally plug into the midranges, so you have to create a ‘Y’ [...]

Since I enjoy tinkering and soldering I am actually delighted by this! Looking forward to manufacturing these. Is the design and components quite ubiquitous for this type of speakers or is it advisable to make any modifications for my specific speakers?

[Billfitz]

All that matters is that it's designed to work with 4 ohm speakers.

[Arthurrs]

Billfitz what are the passive crossovers provided with the HK door speakers? Hopefully a step above the hifi system (which was a paltry capacitor inline with the tweeter)? When the weather gets warm enough I'll be doing some experimentation.

[Billfitz]

From the pictures one can't tell if it's only a capacitor or if there is also an inductor.

[esaru]

Originally Posted by Billfitz

All that matters is that it's designed to work with 4 ohm speakers.

I’ve had a change of plans.
The audio system tweeter does not fit my vehicle. And the mid driver, while it does fit with a included adapter bracket, is much smaller than OEM - only goes down to 250hz as well.

So I will purchase something else.

It seems the biggest difference between available component sets is found in the crossover. Many provides something similar to OEM hifi, or at most a box that does -6 db. So in most scenarios the included crossover is inadequate, requiring me to build my own.

With this in mind, do you have a recommendation for a (relatively) reasonably priced set?

One option that stands out is MATCH UP C42BMW-FRT.2. This set seems to have a somewhat adequate crossover? This would cost me around 260€ which is on par with most alternatives with worse crossovers, so a net win if I don’t have to buy additional components for building a crossover myself.

https://www.audiotec-fischer.de/en/m...up-c42bwm-frt2

What do you think? I expect you to point me to used OEM hifi drivers. These are however of low availability and high cost where I live.

Also, a more general question/reflection:

My only benchmark for this upgrade process is my Volvo V40 with High Performance audio package. Even after adding Match amp and Earthquakes to my BMW it does not seem to compete with the Volvo. Expressed in my limited layman’s vocabulary, I find the Volvo to pack much more of a punch, with more full bodied sound.

The latter does have 4x 6.5” mid drivers. Is the BMW just at an inherent disadvantage being limited to 4” mids? Is this disadvantage of such a magnitude that I should limit my expectations for what can be accomplished in the BMW without extensive modifications to fit larger drivers? Or is it perhaps just a matter of tuning the dsp according to my preferences? Perhaps complimenting the earthquakes with a trunk woofer?

Many thanks once again. Your expertise is invaluable!

[NealfromNZ]

You should be able to get great results with the 3 way BMW setup.


Select a target curve to tune to. Start with Harman/JBL or audofrogs tweak of Harman curve.


1, Optimise the cross over points for speakers installed once you’ve done sweeps for underseat woofers and door midbass
2 , Time align door midbasses and tweeters (this will pull the image up and will center image )
3, Equalize door speakers to target curve left first , then right and then do same for underseat woofers one at a time.
4, make sure woofer running same polarity
5, phase align woofers to door mid bass one side at a time.


It should blow the Volvo away after.
With the earthquakes and door mid basses.

Try not to run the earthquakes much above 100hz otherwise according to one owner that’s into higher end systems they get boomy above that. So your door speaker choice does become crucial.

Trunk sub is the answer if you want good sub bass. Would suggest running trunksub from 20-60hz

[esaru]

Originally Posted by NealfromNZ

You should be able to get great results with the 3 way BMW setup.


Select a target curve to tune to. Start with Harman/JBL or audofrogs tweak of Harman curve.


1, Optimise the cross over points for speakers installed once you’ve done sweeps for underseat woofers and door midbass
2 , Time align door midbasses and tweeters (this will pull the image up and will center image )
3, Equalize door speakers to target curve left first , then right and then do same for underseat woofers one at a time.
4, make sure woofer running same polarity
5, phase align woofers to door mid bass one side at a time.


It should blow the Volvo away after.
With the earthquakes and door mid basses.

Try not to run the earthquakes much above 100hz otherwise according to one owner that’s into higher end systems they get boomy above that. So your door speaker choice does become crucial.

Trunk sub is the answer if you want good sub bass. Would suggest running trunksub from 20-60hz

Thank you! Especially for the suggestion regarding target curves. Was clueless beyond the reference included in dsp pc-tool.

1. Sweeps is in reference to analyzing the input signal? If not, please enlighten me.

3. Should crossovers not be set after equalization? I thought you want just safety crossovers while using RTA to get a complete measurement and adjustment.

4-5. How exactly is this done? I’m pretty sure about my wiring, but should I still confirm polarity? Also fully clueless about phase alignment.

Any suggestion for mids and tweeters? Match set linked above good to go?

Regarding trunk woofer, how large should it be to make a meaningful impact? 12” would do it I guess but worried about wife acceptance factor.

[Billfitz]

The Match speakers may or may not be any better than OEM Hi-Fi or H-K. If they posted real specs one could know, but they don't. The crossover says it's 12dB/12dB, so that much at least is an improvement over OM. There are many non-BMW specific driver options that are better than OEM at much more reasonable prices, for instance https://faitalpro.com/en/products/LF...p?id=401005101 but not having the 3 bolt configuration will require some fitting work.

[esaru]

Originally Posted by Billfitz

The Match speakers may or may not be any better than OEM Hi-Fi or H-K. If they posted real specs one could know, but they don't. The crossover says it's 12dB/12dB, so that much at least is an improvement over OM. There are many non-BMW specific driver options that are better than OEM at much more reasonable prices, for instance https://faitalpro.com/en/products/LF...p?id=401005101 but not having the 3 bolt configuration will require some fitting work.

Well since I have base audio everything is an upgrade!

Would the fitting in question be limited to drilling a new hole or two? If so, this seems like an interesting option! Do you know of any suitable drop in tweeter options to pair it with? Not sure how ubiquitous the OEM design and dimensions are, perhaps tweeters are more difficult when it comes to straying from the small PnP market options?

Can it be quantified somehow how much better those are than for example OEM hifi? Is it substantial or marginal?

[Billfitz]

You'd have to do some drilling, possibly some sheet metal cutting. I added these tweeters to my rear doors. They come with 12dB high pass filters, though you'd still need low pass filters for the midranges. https://www.amazon.com/JBL-CLUB750T-...01MZI2OPE?th=1

[NealfromNZ]

For that door speaker option it wouldn’t need drilling as such , but at that speaker depth an adaptor ring would be used. So 3 holes in the ring for the bmw mounting points and 4 holes for the speaker mount.

At 40mm of depth you’d want about a 12mm spacer ring as you don’t want the speaker to be more than 38mm into the door cavity to leave clearance for the door glass. You also want to use a foam ring on the outer edge of the adapter to it seals against the door card

For adapters there are a few 3d printed stl files on the internet that could be used.


https://m.crealitycloud.com/model-de...473cf6003bad95

This was how I mounted my door mid basses for my base audio upgrade.

[NealfromNZ]

Originally Posted by esaru

Thank you! Especially for the suggestion regarding target curves. Was clueless beyond the reference included in dsp pc-tool.

1. Sweeps is in reference to analyzing the input signal? If not, please enlighten me.

3. Should crossovers not be set after equalization? I thought you want just safety crossovers while using RTA to get a complete measurement and adjustment.

4-5. How exactly is this done? I’m pretty sure about my wiring, but should I still confirm polarity? Also fully clueless about phase alignment.

Any suggestion for mids and tweeters? Match set linked above good to go?

Regarding trunk woofer, how large should it be to make a meaningful impact? 12” would do it I guess but worried about wife acceptance factor.

1-3,5 have a look through this guide as quite a bit to it. Work through a section at a time. The author also has a great YouTube channel ( and Facebook car audio dsp running group )


https://drive.google.com/file/d/1DMb...K2QKiLruZ/view

https://youtu.be/RNlqL5RG2y8?si=OPNj9lLgmYJh5Dif

Also CAF and PSS car audio channels on YouTube worth looking at.

4, simply try invert phase on one woofer channel in your dsp. And then measure bass with both woofers running. Play some drumimg track and you should hear the difference.

6 For a trunk sub a 10 works well. If you get a back trunk enclosure it will give a couple of + db difference compared to being behind back seat. Although at the spls that a sub can produce it’s not really an option. I’ve run my old 10 whilst rebuilding my 12 inch enclosure.

With the 12 inch sub rattling of car was far more prominent so needed quite pannel damping material on trunk lid and floor areas.

Tweeters
Rear door cards are straight forward as plenty of mounting depth. A holesaw is all that is needed.

Front tweeters
You can either modify the bass audio sail to mount by drilling a hole or replace the window surround trim with Harman Kardon ones. However the HK trims are best used with a drop in or clip in OEM tweeter or aftermarket. There isn’t a lot of depth behind due to the mirror mounting bolt being behind.

Have a look through this page for how I did tweeters.I used HK trims and mounts. Used some focal tweeters in my build. Went for the next model up from the focal drop in series which was quite fiddly.



https://f80.bimmerpost.com/forums/sh...1948053&page=3

[esaru]

Originally Posted by NealfromNZ

1-3,5 have a look through this guide as quite a bit to it. Work through a section at a time. The author also has a great YouTube channel ( and Facebook car audio dsp running group )


https://drive.google.com/file/d/1DMb...K2QKiLruZ/view

https://youtu.be/RNlqL5RG2y8?si=OPNj9lLgmYJh5Dif

Also CAF and PSS car audio channels on YouTube worth looking at.

4, simply try invert phase on one woofer channel in your dsp. And then measure bass with both woofers running. Play some drumimg track and you should hear the difference.

6 For a trunk sub a 10 works well. If you get a back trunk enclosure it will give a couple of + db difference compared to being behind back seat. Although at the spls that a sub can produce it’s not really an option. I’ve run my old 10 whilst rebuilding my 12 inch enclosure.

With the 12 inch sub rattling of car was far more prominent so needed quite pannel damping material on trunk lid and floor areas.

Tweeters
Rear door cards are straight forward as plenty of mounting depth. A holesaw is all that is needed.

Front tweeters
You can either modify the bass audio sail to mount by drilling a hole or replace the window surround trim with Harman Kardon ones. However the HK trims are best used with a drop in or clip in OEM tweeter or aftermarket. There isn’t a lot of depth behind due to the mirror mounting bolt being behind.

Have a look through this page for how I did tweeters.I used HK trims [...]

Amazing resource! I’ve come to realize I have treat this as a long term journey, requiring some extensive learning to get a good result. Another hobby acquired I guess!

I think the speaker mounting info isn’t really applicable for my vehicle though(?)

X3 f25 has tweeters in a slot in the actual door card, right next to the door handle behind a small plastic panel. That’s actually something I am yet to deal with. I need new panels with speaker grill rather than the base audio version that is just solid plastic. They are crazy expensive though, the equivalent of 150 $ for the pair. Considering going to town with a Dremel to convert the existing ones. Not very a straightforward job though since the panel is smaller than the tweeter, can’t just drill a hole with the diameter of the tweeter and fit a ready made grill. Pic for reference.

The newer x3, G01, has the tweeter in the window surround trim though. Those are much cheaper for some reason, so I’ve been pondering if they might fit my vehicle. Would be a nice solution since it also raises the tweeter up a bit.

[NealfromNZ]

Have you considered copies/ knockoffs of the grill ?

BMW F25 F26 X3 X4 Series Front Door Tweeter Cover Speaker Loudspeaker Modification Sticker Decoration Original Upgrade
https://a.aliexpress.com/_mqZhgOw

[Billfitz]

The tweeters I linked will go just about anywhere, and they swivel to aim them. These are mine in the rear door: