When you do this, you will find that when you use stiffer materials like Carbon Fiber or even fiberglass stiffened by resin, the sound coming from the speaker will be more natural and fine detail is clear. When the cabinets are less rigid, but still resonate at a high frequency separation of detail will still be good but sound will be damped and dark. The solution is to alter the crossover and make the tweeter slightly more forward.
The alternative explanation of course is that there are no differences and its all imaginary
