I was told the high frequency horns in the large format duplex drivers (designed by Bill at GPA) were too "beammy" for close work. Well they are!!

I say these on ebay last night. I suspect they are RCA high frequency horns. My question is:
Would they be "too big!!" to be placed in the mouth of a ubangi mid-bass horn?
http://cgi.ebay.com/ws/eBayISAPI.dll...MEWN%3AIT&rd=1

I suspect they would affect the throw...but will they work?