Resistors vs.peltz Autoformer- Differences

Nuts, I can't edit the title.
Resistors vs. Paul Speltz Autoformers- Differences?
Bob

Here's the page:
https://www.zuaudio.com/low-voltage/2020/1/24/loading-resistors
It looks like this is only for a few of their speakers.
Bob

Thanks Almarg, et al.
@millercarbon,
Yes, I agree, getting the right equipment is the best approach. I was curious as to how either method worked, especially with regard to sound reproduction.
Given that Zu has signed off on the resistors, I would imagine they find any tonal differences to not be significant.

B

@almarg ,
Correct as always. I was on another thread with millercarbon and got everyone mixed up.
Bob

@georgehifi ,
As I said before, I agree.
I only posted this to get an idea of what is being done and the differences between the Zu resistor and the Spetz Autoformers in terms of how they are operating.
I don't know a lot about such things, and wrote some things that were improperly stated and only rectified when I provided a link to the Zu webpage.
My main concern is: what is the difference between adding a resistor to a speaker vs. the Speltz autoformer? 
Bob

@luisma, @atmasphere ,
I have no desire to add resistors or the autoformer to my speakers.
I was just curious as to the differences between the two methods with regards to how it affects an amps performance, as well as the resulting sound performance of a speaker.
Does this make sense? I'm probably using the wrong words but hopefully you get my drift.
Both seem to allow the amp to perform 'better', but does the resultant speaker sound change with either method?
B

@almarg , @atmasphere ,
Thanks, that is exactly the information I was looking for.
Sorry if I wasn't clear at the beginning.
Bob

@georgehifi .
That isn't what this thread is about.
I just wanted a clear explanation of what these 2 devices are doing.
Ralph and Almarg provided that. 
Bob