Hi Jaxwired,
I'll always give support to someone when I think it's due. Your passion and enthusiasm for music certainly comes accross from you YT videos, and the kit you use, along with all your contributions on different forums. The music is first and foremost. My passion/obsession for music spans over a period of nearly forty years, and I doubt it'll ever end. It's a universal language, and along with sporting events, which showcase incredible talent and dedication, music contains many of the same ingredients to bring people together, no matter.
So, to answer your question. The 12's are a totally different sounding speaker compared to the 8's, in every way. Before I auditioned the 12's I was hoping that there wouldn't be enough difference to justify the cost in upgrading. But unfortunately there was, so there was no going back.
The new midrange driver on the 12's makes such a huge difference, bringing vocals out considerably more than the 8's. Along with all the extra detail, such as the microphone bumps, and the singers breath hitting the mic, if you like that sort of thing. I do. They still have that Fact signature sound, but just a lot more of it. Like a pair of Fact 8's on steroids. Unadulterated, clean, room filling sound. I often sit off axis and they still sound great. The lower frequencies are a world apart from the 8's, with the bass having a lot more to say, to the extent that you do quite literally feel it. Although the bass drivers are small, it makes them fast, so they stop as quickly as they start, and they can really strut their stuff, in a very musical way. And the PMC trademark transmission line does a fantastic job in making a speaker cabinet of this size produce a sound that really does beggar belief. On a daily basis after nearly ten months of ownership, and consistent 7 + hour listening days, I'm still impressed as to how a speaker such as this, can produce a sound which one would think could only come from a much larger cabinet and drivers.
So all in all, a much more detailed, realistic, enveloping, larger soundstage when compared to the 8's, and the sound they produce can go so much louder. But all the time holding the composition together incredibly well, whilst never losing their manners. I've not heard the new 26, but I reckon they must be worth a listen, and it would be interesting to hear how they compare with the 8's. All the time I had the 8's, I felt there was something missing from the sound, and the 12's certainly filled in the missing bits for me. Don't get me wrong, the 8's are a fantastic speaker, but if you were spending that sort of money, then the 26's should be on your audition list too.
The 12's are equally impressive at very low volume levels too, and although the music is quiet, its just as detailed, and the speakers still produce that clean, but quiet, room filling sound. For me they do it all, whichever way you like it. And that accounts for the genre of music played as well too. They are happy with whatever you throw at them. With well recorded music, the 12's excel. And the frequency adjustment is much more effective than on the 8's. A feature I use quite a bit depending on whats playing and how it sounds.
Before taking delivery of the 12's, I had the 8's hooked up to the Altair's, and they sounded like they would burst at the seams! Amazingingly good sound though. I felt the 8's were a much better match when hooked up to my two Hydra's. Though the 12's are a much better match with the Altair's. Plus with the Altair's, poorer quality recordings now sound so much better, which is a real bonus, and has an uncanny way of narrowing the gap. I still have the Hydra's, and wonder if I should try adding them to the equation at some point to see how they all work together. Never listened to the Bryston kit, but I wanted British made, and to end up with that and kit that has been the creation of ex BBC engineers speaks volumes when listening!
The 12's do like power though, and plenty of it. I spent a day auditioning them hooked up to my Leema kit, but at the time I was using two Hydra's, running in bridged mono mode, and they did sound very good compared to my 8's on the same amps. But on the end of the Altair's, its again a totally different story. So, amplification plays a huge part in all of this. At the moment I'm happy, but I can't quite help myself from wondering what a pair of MB2SE's or BB5SE's would sound like on the Altair's?
I'm fortunate in that my nearest neighbours are over a quarter of a mile away, so I don't have a problem with noise pollution. After acquiring the 12's etc, I realised I had to move somewhere that would allow me to totally enjoy the system I had, so I did. And I've never been happier!
All the best.