just caught this thread. brought to mind my very early days in prosound.
my first big project when i got to work at a 'real' sound shop was to go through all the 848 horns in the shop. probably 50 or more of them. legend had it that they had been used in martin luther king's 'i have a dream' speech. not sure if that was true, although they definitely were purchased from the company that did sound for that speech.
at any rate, they had all had long lives lived outdoors. there were also a variety of different vintages, 70v transformers, etc.
i think it took me the better part of a month getting those things even close to serviceable. good times.
i do remember the shop had literally no space to store these things, so someone had rigged up ropes and pulleys so that these things hung in the rafters 2 to a line. clever solution.
i was surprised that the horizontal dispersion was greater when they were oriented 'vertically'. counter-intuitive. but i never bothered to actually look at any of the specs to learn this little fact. goes to show that there is always something more to learn...
brian
edit: added 'interesting legend'