I'm torn between sandwiching everything inside the 21x32x13 cabinet and having a net 3.5 cu ft for the 2226 very close to the ports and .5 cu ft for the 2123. Or building a separate box to sit on top with spikes for the 2123. The tweeter shown will not be the one used but that is the position available.

JBL learned as they went that the "vertical" alignment proved best.

I would also think of separate boxes for each driver. That would also allow for voice coil alignment.

Just my 2 cents worth!!!

Ron

One box for the 2226, another for the 2123 and tweeter.

It didn't occur to me until after I did the design and cut the plywood but the big box is proportioned very much like the 3677 box.

Gonna start with the Vifa 'cause it's on hand and then try the Morel MDT-37 horn-loaded as soon as I have the funds.

I ordered 6.2uF Obbligato oilers and 2.2uF Obbligato aluminum foil for the 3500Hz tweeter cross. 6mH Erse for the 2226. All the X-over components on the outside so I can play with'm.

Should I try a small value resistor across the tweeter terminals?

As for the shunt resistor, I'd use a non-inductive resistor, 2x to 4x the Rdc of the driver. On some drivers it's more important, some less, but it cannot hurt to have additional damping. Values in this range won't reduce impedance much at all, but will give additinal damping. That's important when there is a capacitor in the circuit, because the voice coil is inductive and the two combine form a tank circuit. The shunt resistor helps damp the resonance.