Well, the last image attached, so now I'm gettin brave. The second item is this horn that stands in our reception area.
This horn and driver combination was designed in 1926 by the legendary Bell Labs team of Wente and Thuras (our archives has a correspondence file with Wente). I've forgotten what the horn model is, but I'm sure some WE enthusiasts will fill in the blank. The driver is the WE 555, the grandaddy of all moving coil compression drivers. You will find similar geometry inside of our K-55 drivers, as PWK was VERY familiar with this driver. At the risk of getting scolded, I will say that the 555 is still virtually state-of-the-art. It sports a 2 mil aluminum diaphragm, tangential compliance, edge-would aluminum voice coil, near 25% efficiency, and has a smooth (VERY EQ'able) response from 60-8000Hz. Yes, it does require a larger horn than pictured to get down that low. Go on eBay most any week and you can pick one up for about $2500.
This was initially designed as the Presidential PA system. By 1928-29 sound was coming to the movies, and this driver became the cornerstone of that application. If you take a close look at Mel Brooks' "Young Frankenstein", you can get a glimpse of one of these tripod-mounted. The scene where Fraunkunsteen is enticing the monster back up the cliff.