Not field coil speaker rated, but one of the best videos/sound I've heard on YT (in regard to a vintage horn speaker) may have been done by "johnk" who has posted in this thread.
I think it was an RCA design (not Western Electric) and I'm not certain if it was a rebuild or a reproduction.
Been searching for the video for a few years without any luck.
The speaker/horn looked like an early WE design, but again I think/recall that it was of RCA manufacture.
Audioamp:
I know nothing of the design of the speaker/video I posted, but I do see gaps on the back sides of the horn.
They do not look even/symmetrical to me, but this may be due to the camera angle(s).
DeKay