large or small format driver-and which horn?????

[mraertex]

Hi Guys
I'm new here and loving the stuff I read so far-its great. Now I need help please

I want to set up the following:
*2 way system (Altec comp. driver mid/high + horn and TAD 1601A bass) for music video/dvd and movies mainly in a room about 15' wide x 24'long x 14' high(pitched cathedral ceiling)
*drivers must "fill" room with resolute sound
*crossover will be (anticipated) at around 600-800Hz, based on TAD 1601A needs primarily
*ultimate bass and treble frequency extension not absolutely critical, but would hope for resolute, quality sound in the 35Hz-18KHz-ish range

So with that, what Altec compression driver mid/high and horn options are best suited for this purpose??? I have my eye set on some of the bigger sectoral or multicell horns such as 511B, 811B, 1003B and maybe others. I have no practical experience with such drivers and horns, but do have listening experience with horns generally as in my main system. All comments from practical experience appreciated

Thanks
Alan