Tralen
Senior Member
It seems it is cheaper to send replacements than it is for them to fix the design. One must wonder how much do these headphones actually cost to produce.But a few minutes after that I had an order confirmation for a replacement pair, so at least they're quick to remedy the easy way, if not with a properly engineered solution.
. My two cents. At the point of breakage of the plastic sheath (which is always the same location) the maximum shear stress is T=3V/2A, where V is the shear force caused by the user when they spread the ear cups to don the headphones and A is the cross-sectional area at that point. The demo is done with the headband fully extracted which increases A. A is in the denominator of the equation which means the max shear stress is reduced. Also, he is not fixing the much stiffer upper band. When you fix the stiffer upper band and have the headband fully retracted, the area A decreases and the shear stress increases to 3x the shear force. The rectangular plastic is also curved to provide a restoring force that is used to keep the headphones pressed against the ear when on the head and also adds to the shear force. Changing the formula of the plastic cannot fix this problem. Rather it is a fundamental design flaw in the headband. The plastic cannot resist the shear force. You cannot make the plastic deformable or you will lose the restoring force. You cannot add reinforcement (like metal) to the plastic because it would cause a fundamental redesign of the headband. I think Slate knows this and currently redesigning the headband.
