I find the D7 to be the most neutral and transparent speaker I've heard to date.
My listening friends prefer the D7s without the assistance of my Spendor Sub-3 subwoofer. I kind of like the sub. About the only recording it makes a big difference on either way in the lows department is when playing something with kettle drums played for dramatic effect like Stravinsky's "The Firebird" or "The Rite of Spring". I have the sub set very low, with the crossover at the lowest possible frequency, which is like 50hz. Most people who don't like subs don't turn them down far enough, either in frequency or in amplitude. So of course they're too much for real listenability under those "I can hear it" conditions.
As far as supersonic frequencies go, what we decide to perceive and what we actually hear is as much a matter of faith as it is genuine perception - in my opinion. If your gear goes out to supersonic frequencies or you have to have that because, well because it must be better, great.
For tube gear to go far past 40k starts to cause a new set of problems in design, some resolved by heavy use of negative feedback or other tricks. As far as SS gear or class D gear goes, I won't venture an opinion. As far as speakers go, It's kind of an academic argument.I tend to find a lot of speakers bright as their solution to provide air and soundstage. If you listen through that you often end up tired . . . or cranky.
Personally, I look for naturalness of tone and for my walls to disappear. That is my soundstage. Height cues, depth, front or back, relative positioning is somewhat all in the mind.
Many speakers achieve the supernatural, seeming larger than life. Many listeners crave that. I find it exhausting. That's why I'm writing about these speakers.
In my 13' x 30' space with the speakers in the middle of the short (13) wall, they sound great. So, I'm about 10 - 11 feet from my speakers.
The D7s sound natural with the grilles on.
The A9s sound more natural with the grilles off.
Both have some run-in time before they're at their best.
I can't think of anything negative to say about either pair and I think, if you can relate to my descriptions, you'll find much to like in either pair.