drboar

Hornresp in windows is a free download.

Measuring resistance only tells you state of voicecoil Low=short circuit, High= broken wire/connector. If the voice coil is stuck in the gap resistance will be OK (it will show up in impedance measurements if you do a frequency sweep) A bad diaphragm does not show up in resistence measurements.

If the tweeters are rear mounted flush mounting it will be an improvement. Seal the doghouse with the foam tape used for sealing drivers. Crossbraces between doghouse and sidewalls can be a good idea.

Both Peerless drivers. The tweeter is a classic used in many speakers in the late 70s early 80s like the Polk 10 and many european speakers. The 2" mid dome. There are 2 are 2 way speakers using that tweeter, the problem is then sourcing bass/mid drivers rougly 40 years old to go with them.

Plywood for sure is far more sturdy than MDF for mobile use, bumps and scratches and the occational rain shower. For a stationary indoor loudspeaker however, it appears that bracing and damping/lamination to be more important. There are differences but they are not that huge. Here is a test conducted by the German magazine Hobby & HiFi. The setup is a dual chamber box with a driver in bisecting wall. A board to be tested was placed in front of the driver and both soundpressure in front of the box (compared to no board) as well vibrations of the board was measured Vibrations to the left and reduction in sound level to the right. The referense was the 19 mm MDF at the bottom. That result is inserted in the other graphs for comparison. Not much difference between 16 mm MDF, 19 MDF and 18mm Plywood. Fire retarding concrete chipboard 20mm is better but hard to come by. 28 mm MDF is better but not by that much, 20mm stone is way better, 19mm chipboard is slightly worse than MDF and 19mm blockwood a bit worse than chipboard. These measurements were made in the frequency -amplitude domain, I have seen measurement in the time domain and they show most effect of bracing and lamination more than the instrinsic qualities of the board.

At resonable temperatures the speed of sound is lineary proportional to temperature, in Kelvin that is. If we imagine the air above the fire as a hot cylinder, hotter in the center. If a wavefront hits this cylinder the wave in the middle will accelerate more than the wave hitting the cylinder off center as the path lenght is longer and the air hotter through the center. So the wave will become more circular in the horizonal plane and less sound energy will reach the listener in front of the speaker. So the heat cyliner will work as a lens. The lens action works when the pathlenght through the hot cylinder is a sizable fraction of the sound wavelenths. If the rising air is to deflect sound the soundwaves has to be lifted a significiant amount during the less of 1/100 of a second it passes through the heat cylinder. As there is a vertical heat gradient in the air column that gradient will deflect the soundwaves upwards in a similar to the previous description.

I built (long time ago) a Klipsch Horn Clone. I built it in 19mm chipboard, keeping the horn flare as original and then slightly smaller chamber. So the sturderier the better.

You could also extend the horn throat into the doghouse, that would also extend the length.

LTH-142 with a good driver would work as a two way system. Try that first with maximal baffle loadning of the horn, if needed add a tweeter.

FaitalPRO LTH142 and a driver that you like. Realy good horns, I have the slightly smaller 1" variant.

With a 12" woofer you can extend the hornpath with a short straight stub into the doghouse, extending the bass some few Hz. I would rather look into that then scaling down the basshorn and getting the midrange horn even lower.

I still have those Cobra cables

I am quite sceptic to the value of very expensive cables. However, good long time quality is important. in 1988 I bought two loudspeaker cables. Some booring looking Supra 2.5mm2 cables and some Monster cable copies shiny and fat. 2-3 years later the latter had the copper turning green, probably due to reactive components in the plastic. If I peal of the plastic of the supra 30 years later it is still coppery and shining! So head for Madisound and Supra! There are many other brands that I am sure ar good as well, but as a Swede and a happy customer I want to push Supra a Swedish brand🤔.

I bought some vintage Ortophon speakers (In Sweden).They contained Scan-Speak drivers. A site in Japan offered to buy them at a very good price. However, I had to pay for the shipping (expensive !) and they would give me their final price after inspecting the drivers. All in all at maximum price a would make a small profit otherwise I would make a loss at the sale... So the point is value depend on were you have someting. So the vintage Dalies would probably go for less than 500 USD here. If you can fill a container with similar goods you could make a profit selling to Japan but not with single speakers.

The Eminence Kappa-15C i supposed to be a really good alternative. 129 € at Thomann