[Beet Farmer]

The desire for the resistor adjustment was partially brought about from AC upgrades. As i cleaned up the AC, the system became leaner sounding. Over the years, and well before I owned the 20.7 Magnepans (I previously owned 3.6 Magnepan) I was balancing the sound between sounding a bit too lean vs wanting more clarity. All with AC conditioning, power cords...
So IMO the room has nothing (at least to my needs) to do with the sound.

On the other hand, one should realize the resistor is 'part of the Magnepan speaker'. It is not there as some sort of 'band aid'. The owner's manual says point blank it is a tone control (at least as revised 2019 version) I understand the desire to be a purist on the resistor thing. My generally being an iconoclast makes it easy to ignore such desires.

To me the only problem is the poor quality of the stock OEM resistor, which if added really degrades the quality of the sound.
Mundorf 10 watt, or the 20watt (if the rivets are removed) are a cheaper compromise that sound OK. But I have to say the Duelund CAST are the ones to get (once the approximate value one wants is determined). Even though the Duelund are rather problematic to work with.. due to the way the lead are made, and how the silver they are made with is unfortunately easily work hardened. Plus they must be 'carried' and not just hung on the back via the leads.. MY curent way of caring for that is really ugly looking, though practical. Would be nice to have some simple clean little case to enclose the resisotrs to releve any stress on them...
At this moment I am trying a Duelund resistor 1.15 ohm combination.
(I am pretty much certain the tone I want can be had with a midrange resistor somewhere between 1.0 ohm, and 1.2 ohms.

One point I would make is my particular adjustment would probably not be valid in some other system with 20.7 Since so many other parameters are different. (there is no 'one size fits all')

As for my actual room, 11' 8" wide. 27' deep Speakers at narrow end, 18" from side walls, 42" and 54" from rear angled in a lot, tweeters 'in'
suspended floor, back wall brick, large window. to sides behind speakers back heavy lined drapes, to back sides bookshelves floor to ceiling.carpeting on pad. I sit closer than halfway in room, Equipment rack to left behind me.

Slightly more reverb than I would lie from the wall behind peakers. I need some diffusers.. Probably will eventually make some 'skyline' type for back under window, over window and at least something in window like planters? or similar (Some residential restrictions on what is allowed in windows...)