World-reknowned speaker designer, Phil Jones published an interesting paper on loudspeaker impedance. It's a technical, deep dive into the subject but highlights the difficulty in putting faith published speaker specifications for nominal impredance.
What's that sound?
The Microscopic World of Analog
Everything you need to know about Phono Cartridges - By Ortofon
There are many different set-up regimens out there. I have have heard good results from most of them - if the process is carefully implemented. The one, devised by Jon Hunter (then at Sumiko), relies more on "tuning-by-ear" than some of the more rote methods which adhere to formulae and measurements.
