Well it's a fool's game to try to guess a speaker through a youtube video. But I'll play the fool
What I hope: Joseph Pearl Graphene.
What I think it might be: a Vivid Audio speaker.
Why?
I see that people have been guessing it's the JA Pearl based on your enthusiastic response to hearing them at the audio show. So that makes sense.
Also, the sound in your mystery-speaker video does have some of the character of the Joseph speakers, in particular a sense of clarity and vividness.
I'm a big fan of Joseph speakers. Started when I heard the previous version of the Pearl at a show (rarely heard a vocal track sound that real and human), then I auditioned the Pulsar stand mounted speakers, and eventually purchased the floor standing Perspective model. The Joseph speakers have a particular character that seems to stand out, noted by so many listeners and in almost every review: a purity of tone and clarity. It's not just the clarity one often hears from the latest metal drivers, it's not anti-septic, it's rather this utterly grain-free purity, like looking through a stream that has been completely cleared of silt so the vividness of the colors of the rocks in the stream bed come through. Vocal and instrumental timbres seem to come through the Joseph speakers in a similar colorful, clear manner. (Vs some versions of "clarity" that can seem to blanche instruments of timbre and tone). It's an amazing combination of super clean yet relaxed.
This is also helped by the fact Joseph has made sure that there is a richness to the sound, especially from the lower midrange on down. So it's this luxurious combination of "clarity, speakers disappearing" but also with a richness and a fun sense of punch and drive. Such a hard to find combination. "Un-mechanical" sounding, as Michael Fremer put it.
(The Joseph speakers don't ultimately have as much richness or fullness as some other speakers - e.g. a Harbeth is going to give voices even more body, texture and presence. I've owned both brands. But nonetheless the balance Joseph has struck is very enticing).
And having heard practically every Joseph Audio speaker video on youtube, I've found that some of that character - the clarity and lack of boom etc - seems to come through.
So back to the mystery speaker. In the video it *sounds* like a familiar openness clarity and detail one gets from the Joseph speakers. I recognize a certain signature there. Except that it's a leaning a bit more to the anti-septic, lean side of the spectrum.
It sounds more like what I've heard from the Vivid Audio speakers (I've auditioned a few, and a friend has had them in his home and I listened to them often). For me the Vivid speakers offer some of the Joseph characteristics in terms of boxless presentation and clarity and vividness of detail, though pushing that even a bit further, and also with a bit more "slam" and force available, but also for my tastes, a bit too far to the analytical and lean. When I'd play some of my demo female vocal tracks on the Vivid speakers, I'd get a super "vivid" image of the singer, but it tended to sound more artificial, hyped, lean, electronic, whereas when I'd get home and listen to the same tracks it sounded more like an actual human being.
So...again...my hope is that it's the Joseph Graphene because I'd really enjoy seeing what you think of that speaker in your home. And from the video, sonically...it still could be that speaker.
But I'd roll the dice with a Vivid speaker. (I haven't seen enough of your videos to know if you've expressed enthusiasm or desire for any other particular speakers, which is why my guess is so constrained).
Cheers.