The ERGO model 1 and 2 utilize rugged and reliable dynamic-type reproducers. Both models can be connected directly to the standard 6.3 mm (or optional 3.5mm)
headphone sockets of a stereo amplifier, receiver, tape deck, CD player, TV and PC.
Here a short description of the ergonomic for the headphones
A) The ERGO headphone rests lightly on top of the head, the weight, mere ounces, distributed over a large insensitive surface. This light weight and soft foam headband cushion result in complete freedom from pressure and allows the scalp to “breathe” naturally.
B) A foam strip, at the rear of each speaker panel, rest lightly behind each ear. These do not contact the ears to cause any deformation, which would obstruct the natural sound field created by the speakers.
C) the speaker panels are fixed in the correct position to maintain optimum vertical and horizontal angles of sound dispersion.
D) Since the speaker panels do not physically contact the ears, the intervening spaces permit a fresh air-flow from below the ears, which avoids the heat, perspiration and listener fatigue so commonly experienced with conventional headphones.
Conventional headphones distort the shape of the outer ear and pump sound directly into the auditory canal depriving the ear of its natural function.
Such headphones may have a wide frequency response, but by contacting and deforming the ear they lose or distort the second (indirect) sound wave information, resulting in unnatural sound reproduction and listener fatigue.
https://www.precide.ch/eng/english.htm