ADS L810

IF you want to troubleshoot, start with a physical inspection of the voicecoil lead in wires on the tweeters and midrange domes, these are quite delicate and routed on the front plate. The adhesive can fail over time, leading to flex and or breakage of the wires. Check the woofers also, gently and evenly push the cone in from near the edge of the dustcover but not on the dust cover, listen and feel for a mechanical rub. This is NOT a conclusive test as the voicecoil may rub with power applied which heats it up/ expands. Listen up close to each driver to see IF you can hear source of distortion, IF you can isolate, then you can swap in good drivers and or the other crossover to isolate.
hope that helps.
You can facetime w me IF I can be of assistance.
Jim

That speaker is getting so old that it might have troubled electrolytic capacitors in its crossover, too.  tomic601's suggestion of crossover swapping would prove that angle out, as well.

Thanks to all for your quick responses and suggestions.  I have already contacted Richard So about my issue.  He seems to be the right person to address the problem. I plan to further troubleshoot and send him the component(s) in question at the beginning of the year.

In the meantime, I hope everyone has a wonderful, safe Holiday Season!