Making a new sealed box for my 2-way

I have a very good sounding two way box, using an excellent 8" low-mid and a soft dome tweeter.

The woofer was designed and built by a friend of mine who manufactured and sold speakers in Argentina. Unfortunately he passed away about two months ago, and we didn't get to do this mod together. So now I am on my own.

The idea, as we talked about was to build a new larger box, holding all three drivers. We were still going to see if there would be wood plate separating the 8" + tweet from the NHT 1259 sub bass speaker. A separate amplifier would feed the NHT, with passive 2nd or 3rd passive low pass eq on the amp. The sub output would be fed from receiver RCA output. The idea was not to use a large inductor as passive crossover on the sub box.

Unfortunately that option would force the use of just one sub for both channels. My late friend had done many tests and measurements on his premises and he arrived to the conclusion that what is always said that very low frequencies presented themselves as just one single wave, instead of two different ones for each channel is not exactly so. There is some space localization that you can do at low frequencies too, which of course depended on how low your ear listened down below. It was not really "listened" but "felt" as placeable.

In any case I think it's time for me to make MY tests, on MY system and MY room, listening to the music and home video audio I listen to. And see what I find on this matter.

I already bought the measurement microphone, and I will use my laptop and REW software to make first my 2-way measurements and see how low in bass can I reach on my room, without adding a sub. That is where I will start from.

The next test will be with a single woofer with the 12" NXT 1259 I already have, in a closed box. I will aid the sub with a Dayton DSP little box, to see if I can make reach lower, at least down to 30 or 35 Hz @ -3dB. On this test I will move the box around to listen if I can locate it. If I can then it would prove that using two L/R right subs are a further improvement.

Then I will build two larger boxes for left and right as I describe above.