Choosing a HF driver and horn

[whaleboat]

Hello , I'm considering building some pa speaker cabs . They'd be 2x12 using eminence Delta Pro 12A's rated at 400w RMS each and about 99 sensitivity . What I'm wondering , is if there is a basic rule of thumb for matching up tweeters to woofers . I'd be using a compression driver/horn set-up . I've also cosidered building a 4x12 with dual compression drivers and horns , any thoughts on that ? Thanks for any info you might be able to give me .

[greywarden]

The H6512 horn and D220ti is probably the best, least expensive way to geta smooth top end. Look up the "Flex your PCD Mettle" thread for econowave designs, it's all figured out for you

[billfitzmaurice]

if there is a basic rule of thumb for matching up tweeters to woofers..

Dispersion. For good results you must cross from the woofer to the HF section below where the woofer starts to beam. With the average twelve that's no higher than 1.5kKz. Crossing over too high, resulting in an off-axis trough between the woofer and HF section, is the most common shortcoming of most commercial 2 ways.

I've also cosidered building a 4x12 with dual compression drivers and horns , any thoughts on that ?

Unless laid out as a W-W-T-T-W-W, don't.

[whaleboat]

Thanks , that helps .