Speakers The single most critical component


I know we've been over this Q hundreds of X's over the past 20 years here on audion, You can find dozen of topics dealing with this Q <which is the ,,,,most important component...>>
well time for yet 1 more topic dealing with this,, perhaps unanswered, un-resolved issue.
I'm bringing up the old hachet due to my recent experience acutally hearinga FR in my system. 
Let me tell you, there is not even 1 traditional/conventioanl/xover design <The Boxed Type>> in the world that could convince me  , there is something that will beat out FR (caveat, FR requires  some sort of high sens =sensitivity, tweeter)  in  the Boxy world of speakers.
That is to say, FR + Compression Horn is the future of 21st Century high fidelity. 
One lab has already brought us these ~~~SHF~~~ aka SuperHighFidelity  single drivers. 
The code word here is ~~SHF~~~ which can not never be employed when describing xover/trad/conventioanl style  aka The Box designs. db level under 91 are _<<IN-EFFICIENT>> , = dysfunctional, out dated, old school , = Dinasaurs. 
For amps, I only consider tube amps (PP and SET) as ~~SHF~~~ I can not include ss amps in this topic. 
IMHO all well made tube amps sound very close,
 a  kt88 in brand X will sound  close to brand Y. 
So amplification takes a  distant 2nd place in critical component.  No need to break the bank buying amp A vs  a  lower priced kt88 amp B
CD players, nearly all  tube DAC's , tube cdp-ers sound  close. No need to braek the bank over X vs Y.
My Jadis DAC is  only miniscule gain over the Shanling,
 the Shanling
only a  miniscule gain over the Cayin CD17. 
Now as for  best source  , phonograph is the ideal playback medium vs cds. 
I have some LP's now , but my main collection are classical cds, most not on LP version. Cables , I did note some gains employing silver/copper wiring throughout my entire system including inside the Defy.
Tweak worthy.
New Mundorf caps in all componets, tweak worthy. 
Yet the main central component remaisn the speakers.
Here is where  the entire audio resolution either rises to Nirvana or falls to <<distortion/muddy waters,/pollution/anti-fidelity  voicing  issues.
Your system's fidelity is ultimately dependent on what speaker  you have chosen to employ.
Forget all you've learned over the years, 
The new mantra is <,The speaker is key component>
All else is just extra tweaks/nuances. 
To sum up, a  ~~SHF~~ driver will match even the top of line Wilson weighing in at hundreds of lbs priced $$$$$$$ overa single FR driver. 
FR beats out any/all xover box design speakers. Mostly due to that key specification ~~db level~~~ which is everything in speaker design and thus in resolution/fidelity. 

mozartfan
So I double cked the google results on <Field Coil>> scrolled down and hit  on this April 2021, Ht Off The Press Field Coil  design from japanese technicians.
Its long article , but  will hold your interest, I just fliped through it and came across something that confirmed my hunch concerning more complex music in a  FR driver, PP ~~may be~~ the better option.
My hunch was validated. 
The golden rule of SET amplification ~~Only~~ for FR high sensitivty speakers, may need  a  tweak in the theory. 
Field Coil is not my interest,  for budgetary reasons.
Still , concerns my main thrust to my arguments agaisnt xover old designs. High sensitivity is the future of speaker designs. Due to the higher effectivity producing a purer higher fidelity in the musical ambience.
Loud-speakers are a thing of the past,  
A new day is dawning.

https://www.dagogo.com/feastrex-makoto-loudspeaker-system-review/

Post removed 
The first question I will ask is why you are so insistent that a full range driver is the ultimate in reproduction. When we look at psychoacoustics, brain operation, I don't think there is a good justification for it.

The concept of time alignment of all drivers sounds like a great idea, but somehow speakers that are not perfectly aligned still sound as good as ones that are. Why is that?

The reason is likely that the ear/brain uses a very narrow portion of the audio band, about 200-1500Hz to extract timing information. That is it. That is where all the timing information comes from. If you are aligned in that area, you have done what is needed. Even then what matters is both speakers are the same, not so much alignment. 


After that, frequency response and distortion dominate, and full range dynamic drivers will always have doppler distortion worse than multi-driver systems. It is unavoidable. They also tend to have higher distortion.  It is a technical solution in search of a problem while creating other problems.