Help with vintage dual 12” FR speaker build

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I am hoping to start a build over the winter/spring using some vintage and very nice sounding full range speakers. I have the following components, and would like to build new speaker cabinets using both of the following drivers listed below, and would like to figure out the best suited crossover for such a configuration;

Pair of Soundcraftsmen 2640TX 12in co-axial drivers (woofer + horn, some call these tri-ax as they also use a whizzer cone, but I believe they only have a simple hi-pass using a paper/oil cap from the woofer to the horn)

Pair of Stephens Tru-Sonic FR 120 12in full range drivers, these are just one full range woofer with gold dust cap in the center of the woofer, which seems to be aluminum.

These would be powered by a pair of Fisher 660A stereo power amps (7591A power tubes) that would be horizontally bi-amped, providing a around 20-30 watts to each driver.

My goal at this point is to have an external crossover with stepped L-Pads to adjust the mid and high frequency, and with a bi-amp inputs so that one Fisher amp drives the Stephens Tru-Sonics for the low end, around 1.5kHz and under, and then the other input is driven by the other Fisher amp, with a selectable crossover to the horn at either 6.5kHz or 8kHz. I really want to build something in the vein of the Altec Big Red Mains found here;

Altec Big Red Mains w/ Mastering Lab Crossovers Sound Factory | Reverb

However, I think I would like to build them in a smaller footprint cabinet, specifically something more like a floor standing cabinet so as to conserve floor space as well as have them sit at a friendly listening position level (something like 47” or there about, from the floor). This is about the closest picture I could find of something like what I’m picturing, however the horn in this picture would be replaced with the Soundcraftsmen driver with it’s horn;


I have found some Theile Small Parameters listed online for both drivers, which give me a good starting point for figuring out cabinet volume needed, but I’ll tell you now, I am a beginners beginner when it comes to any of this. The facts are this though; I have always wanted to build my own set of speakers, I know each of the components I have sound very good on their own, I have good carpentry skills, and have a number of years of audio experience working in recording and mastering studios, so my understanding of acoustic principles is pretty solid, as are my soldering abilities. All that said, I’ve never built a speaker box, nor a crossover. This is an overly ambitious project I’m sure, but anything worth doing usually is.

Any input anyone has on this project, I’m all ears and look forward to any and all commentary on this project moving forward.

Thanks in advance!

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