eye height

Standing eye level for men is on average 1540mm to 1785mm,
and 1440mm to 1675mm for women. thus, the average height for both male and female is 1610mm.
hence the measurements for the median box heights gained. Double this for the circumference of the horn. 3220mm (feasible?)

image notes: Illustration of the geometrical rules of optics that express the height of the object as a proportion of the perceiver-actor’s eye height (i.e. an eye-height ratio), where Y is the object's total height, E is the portion of the object below the horizon, and y and e are the respective heights expressed as visual angles. The height of the object depends on the eye height and is expressed as a visual angle: Y/E = 1 + tan(y-e) / tan(e).