If you feel comfortable, open one up to inspect the crossover. If you see any Electrolytic Caps, Iron Core inductors, or Sand Cast resistors improvement is possible. Good Poly Caps, Air Core Inductors, and quality resistors are a step up without changing the crossover design. Check for any steel in the signal path. Recently found steel nuts and solder terminals buried deep inside the connector assembly of a multi $K speakers. Missed that detail when previously doing a complete rebuild of the crossover with good quality components that significantly improved clarity and dynamics. After bypassing that entire assembly with tube connectors another improvement.
You may ask, are you sure Placebo effect not involved. First, the crossover rebuild was done to one speaker. Measurements and listening confirmed differences between stock and modified. Improvement after tube connectors is based on listening to a couple very, very familiar tracks. Both had a slight rough edge at specific points I noticed every time. Chalked it up to recording quality. However, after removing the steel parts from the signal path the rough edge completely gone.
For speakers difficult to ship to Danny, just a DIY parts replacement should help. At the very least you will eliminate possible future problems.
