Please look again at the 4430 spec sheet:Originally Posted by frank23
http://www.jblpro.com/pub/obsolete/443035.pdf
There's virually no highs lost at 10° up (Fig. 5) and that's where the time-alignment is optimum, as well, with the stock crossover and the horn mounted 1" forward of the woofer.
I'm not arguing against raising the horn, as you like, rather, merely suggesting that it's not so necessary as might be assumed from experience with other horns. Constant directivity works here; 4430 translates well as a home floor-stander....