Cast aluminum horns are generally much more resonant than properly designed horns made from less resonant materials (like plastic and wood), and will usually benefit significantly from efforts to damp them. Once damped, aluminum horns have a sonic signature that is a function of the horn shape/flare, the compression driver and the interaction of the two, just like good plastic and wood horns. I would suggest that you stick with horn/driver combinations that have an established reputation for performing well, and that will meet the particular needs of your application. Is this for a home music system or a commercial pro-sound application? How much amplifier power will be used?

If this is for a home system, you might consider a simpler, lower order network. At your crossover frequency, the Eminence horn/driver combination used in the Pi Theater 4's would work quite well at relatively low cost. Unless you are into head banging or live level train/helicopter sound effects, this combination can be used safely with a second order network (at 2 kHz). On the other hand, if you are more interested in getting there and less interested in how you get there, you could just use the Pi network that is the closest match to your drivers and adapt as needed with help from the folks on this forum.

Regards,

AstroSonic