My only maintenance on them, in the last 30 years, has been to clean the level pots. Here’s hoping that my Axiom subs do as well!
The pots are the components giving me problems too. I can't really call it a design defect, who'd imagine that a sub would last this long. Even the foam surround is in pristine condition.
I'm currently researching what makes for a musical subwoofer. I'll post my findings to the forum, but it's difficult to find scientific papers on the subject (particularly why 1.5x is the threshold for group delay audibility at bass frequencies), just lots of pragmatic ones from DIY assemblers and bloggers. It might be the one case where things sound better when you throw a lot of money at it.
