I did a google search on Electro Voice E-V 16A and the first return was a link to a pdf of the brochure from Electrovoice circa 1964.
It's a 3 way air suspension design; 12" bass, 5" cone mid and 2.5" cone tweet, x-over 700 and 3000 Hz.
Bass driver has a free air resonance of 16Hz.
The diagram showing ideal listening distances/speaker angles is not considered correct these days - 60 degrees included angle is the industry standard, not the 30 degrees - 40 degrees indicated.