Thimios, don't worry too much. If the area under the woofer is filled and also behind the woofer on the back wall about half the depth of the cabinet, then all is ok. Like in this sketch:
I pasted the bare walls next to and above the woofer with leftover pieces of an insulation material, but you can also just put a layer of the mineral wool here and not have to buy extra new material.
And also don't worry about the crossover. Whether soldered or connected with Wago 221, makes no difference. I have measured both, listened to and even at times had one variant each in my stereo setup. Of course, unnecessary resistors should be avoided as with cheap terminals, here I would recommend stable and safe connections.
I pasted the bare walls next to and above the woofer with leftover pieces of an insulation material, but you can also just put a layer of the mineral wool here and not have to buy extra new material.
And also don't worry about the crossover. Whether soldered or connected with Wago 221, makes no difference. I have measured both, listened to and even at times had one variant each in my stereo setup. Of course, unnecessary resistors should be avoided as with cheap terminals, here I would recommend stable and safe connections.
This is exactly what you have to do,You should see resonances in the impedance curve of the empty box and how they disapear if you add damping material. The best point is found if additonal damping does not lower the resonance frequency any more and/or all small resonace peaks are gone. If the resonace of the box rises, you have used too much wool. This is theoretical, in practice a loose, complete fill will be just perfect.
As a last, use a large square sheet of wool and place it behind the driver. This is to prevents loose pieces of damping material to touch the membrane.
This is not rocket science, don't spent day's on it!
I can easily measure far, far better than any human can hear. So where's the measured data to support the anecdotalm claims? I'll bet there is none. And before you tell me to do it, no, you're making the claim so it's your job to back it up, not anyone else's to disprove it.
I regularly use Ag solder, and have for decades, because it often flows better, but I have never, ever seen any evidence it has any material sonic benefit.
"High end" means marketing BS to separate the gullible from their money.
An impedance measurement usually shows the interference better, since the room almost always plays into the SPL measurement. In principle, however, both methods work.
But as I said, you don't really need any measurements if you set up everything as described.
Read this page with the help of a translator. Anything is well described, if you have buid a speaker before. There is one woofer, but two options for the compression driver, as the Tymphany is not available (Like most well prices drivers of this brand, as they seem to turn them selves into an expensive brand, like some other, former very rational priced Far East manufacturers do.) The low priced horn is sometimes hard to get, too.
https://www.der-akustische-untergrund.de/speakers/power-hifi-projects/asathor-preiswerte-männerbox/
https://www.der-akustische-untergrund.de/speakers/power-hifi-projects/asathor-preiswerte-männerbox/