First, if you really want an idea what your speaker drivers and crossovers will do you need to use a proper simulation software. I really like Vituixcad:
VituixCAD Loudspeaker simulator
Second, in my experience "textbook calculated" crossovers are ALWAYS A TOTAL DISASTER.
You do not need a PCB for a crossover. Given the physical size of components it is best to hardwire them on a suitable piece of plywood (not MDF). Keep it external in order to be adjust things like L-Pads etc easily.
Very ambitious. Every single way adds complexity. Doing that with passive crossovers is challenging.
Outch. 12" is the size for lower midrange, not a bass driver and 630 Euro can buy a lot of drivers that are better suited to operate as "bass". And you may be able to buy several drivers per side for the price of one SS driver.
I would go as far as suggesting that making at least the LF section active (like was on some Harman Sub Brands, like Revel & Infinity) and adding some parametric EQ to deal with room modes will be a MUCH better choice.
Using non-traditional enclosure systems (dipole or cardioid woofer systems) should be seriously considered.
Not a bad choice, I liked the Wavecore WDF182BD0X series better. They have a more advanced linear magnet structure. Given the low sensitivity and small diameter multiples will be needed, maybe 4pcs in an array? This will also give improved directivity control over single drivers.
Alternatively, a suitable 10 - 12" driver may be better suited for the lower midrange role.
Overpriced, underperforming. Poor directivity control.
It is better to use a spherical wave waveguide (some might say "horn") with a dimeter similar to the woofer, if using a large driver (10-12") coaxial arrangements may be considered.
Otherwise, I like the ring radiators with a large waveguide. Note that these will need considerable equalisation, because the constant directivity causes a non-flat response that will be maximum SPL at the lower cutoff of the waveguide.
Again, over priced, under performing and probably unnecessary. Using a decent waveguide loaded tweeter will likely extend high enough.
What makes your chosen crossover points "correct"?
This is a VERY LARGE single enclosure. I would consider splitting this into multiple boxes to stack.
Very, very seriously consider to use a different cabinet material, or if you must use MDF, consider an "applique" layer of artificial or real stone.
So-called "black galaxy" granite from India is affordable in 12mm and gives a polished high gloss surface and makes for a very inert cabinet. These are used for kitchens and bathrooms, so making cutouts with a champher or roundover can be left to the Stone shop.
The higher the LF driver is placed, the greater the influence of the so-called floor notch.
This should be analysed and normally placing the woofer as low as possible and placing the midrange at about ear height and setting the crossover to keep the floor notch out of the lower midrange drivers operation range is a good choice.
This seems relatively high for a seated position.
This leaves a large distance between lower midrange and upper midrange.
This will lead to comb filtering and places the tweeter axis nearly at standing height (defo for my GF).
Normally I would aim for a seated height of 1m and place the HF Axis at ~ 1m height, unless there are very good reasons to place it elsewhere.
Yeah, don't do that, see above.
Lower midrange needs a separate enclosure.
That's a lot of wasted space.
This is near impossible. Each driver is a 2nd order bandpass device. So unless you create huge overlap between drivers, you cannot ever achieve a 2nd order acoustic crossover. And the acoustic crossover is what matters.
I would suggest to spend some time looking into speaker design and reading a few good books and websites on the topic, before continuing.
IF you were to consider my advise, I would do the following to come somewhat close to your original idea of a massively tall speaker that would have impressed the people who erected stonehenge (which I wholeheartedly approve of).
Go fully active with a DSP crossover and get a measurement microphone (from MiniDSP). It is much much more likely you will end up with a well working system.
Use high quality linear (non-switching) Amplifiers for MF & HF - my recommendation would be a few of the pre-build LM3886 based Amplifiers you can find on Aliexpress. Woofers, Class D will be fine, you will need a lot of power.
Make a Mid-Hi MTM array with a waveguide equipped tweeter similar to for example Amphion:
View attachment 112673
Use two woofers and place one at floor level and one at the top of your enclosure.
Split your actual ~200cm tall enclosure into three sections, the middle one with tweeter height at 100cm and 60cm tall and the two woofer sections 70cm high each.
You can make this a narrow "tallboy" by mounting woofer in the sides, but instead I suggest that a wider and not so deep box is preferable if you can accommodate it in terms of decor.
An old Dynaudio design (Myrage) implemented a similar design with 2 X 12" Woofer, 2 X 3" Dome and a 1" Tweeter. I heard some recently, they are still an excellent speaker.
View attachment 112674
I would probably suggest much more radical designs, if you were to ask me.
But something like a Myrage or similar, using a fully active system and suitable DSP crossover is 99% assured to give great results and is actually manageable as build.
Finally, a website to consider reading about speakers (not mine):
DIY-Loudspeakers
There are also many excellent projects completely worked and reasonably easy to replicate. Here a scan speak 4-way similar to your ideas, FWIW:
Ellipticor-A50-mkII
Thor
I am doing some more research at this stage and recalculating everything, I am even considering using cheaper drivers for the build, but nothing is final yet. I just realized I need to put more time into this, so I am sure to get a good result. Once I am further in the process, I may well draw upon your resources, thank you so much for being so generous!!
