Bill,13,5000 / freq(in hz) = wavelength
for 800hz = 16.875"
You want 1/2 wavelength (8.4") distance between the VC's using 2nd order crossover.
The 2226 VC is 3" behind the mounting backside.
Using 3rd order crossover, I don't know what to do. In the past I have used the same formula and it worked for me.
I currently have 2426J on Martinelli horns and trying to figure out where the VC on the 2426 is. On Altec drivers there is a metal band that goes around the driver that lines up with the VC.
Ron