I don't see, with all of the advice given, where anyone has stressed the need to examine the corners.
millercarbon:
Also you might want to check out the Decware site where he has a very interesting analysis that explains why corner treatment as I have done is so effective.Only the one comment and the two web page links.
https://www.theanalogdept.com/c_miller.htm
https://systems.audiogon.com/systems/8367
Probably everyone else missed it too.