. Have you tried an electrostatic setup as well? I know Smyth previously recommended an entry level Stax earspeaker to pair with the A8.
As a longtime (from the early 80's) "only Stax" user, I am only able to comment on five models of Stax open electrotats, and not entry level. Also, three Stax amps, the last two of which have been tubes (ever since first being available from around 1995).
Before Smyth's A8 I had used at least three manufacturers' version of Dolby Headphone "virtual surround" software (built into their own hardware devices) through the same headphone/amp equipment, and suffice it to say there's no need to discuss comparing them. When the A8 finally became real in 2009 that was thankfully the end for me for Dolby Headphone. It's only been SVS and AIX personal 5.1/7/1 PRIR captured in June 2009 that's been used ever since, and only through Stax headphones (SR-Omega and SR-009) and Stax amps (SRM-T1s and SRM-007tII). First on the A8 and more recently on the A16.
I've listened to several other headphone types (all closed), and never thought them to be as "enjoyable" as the open Stax type. Didn't matter the audio material, no matter 2-channel music stereo or multi-channel video-related audio, everything just seemed to sound better to me listening through my Stax electrostats.
Now comes the A8, and the opportunity to get a custom personal 5.1/7/1 PRIR made at AIX (unfortunately no longer an option). What a miracle. Just a fantastic sounding room when you sat in it and listened to anything. But nothing can really prepare you for the surprise of hearing the A/B-comparison at the end of the calibration session, to be sure that the PRIR/HPEQ actually DUPLICATES THE SOUND OF THE ROOM. Because that's what the Realiser is really for... to DUPLICATE THE SOUND OF THE CAPTURED ROOM, reflecting all of the parts and pieces that went into making that room sound the way it did. All of the electronics, speaker sizes, types and placements, floor/wall/ceiling baffles and treatments, etc., which went into producing the sound as your ears/brain hear it, during that measurement session, sitting in the chair you sat in at that precise location, it all gets "captured" through the microphones and the PRIR technology.
And when something then gets gets played back "in reverse" through that very PRIR, and through the very headphones used to produce the personally measured HPEQ that characterizes of that physical headphone as your ears/brain hear it... well you're not really expecting what the A/B-comparison effect will actually be. It's always like "...wait, did you turn the headphones on yet? Am I listening to the speakers or the headphone? Which one is on now??" You're really not prepared for this, and it always makes you smile. Like you've somehow been tricked. But you really haven't been. It's real.
Now I thought listening to CD-audio music through my SR-009/SRM-T007tII without any SVS, but purely direct from the CD source, was fabnulous. And sure the sound was considerably superior to my older SR-Omega/SRM-T1s, as would be expected. It was noticeably more "clean and real" and with a larger out-of-the-head but still "intimate" sensation that told me I was still listening through headphones, albeit much more precise and transparent and fantastic ones. But I now find that I prefer listening to the same 2-channel CD audio through my AIX PRIR (either 5.1 or 7.1, as they had the same L/R/C speaker placement, and either through the A8 or A16), that it really is subjectively more "enjoyable". I see/hear the sound coming from "speakers in front of me" rather than "around my head, but directly into my left and right ears". It's like the enjoyment of sitting back in your chair in a real room and listening to the sound coming from the speakers in front of you... exactly as I heard sound in the real AIX room, sitting in the sweet-spot surrounded by real speakers.
So that's what this is really all about. The ability to DUPLICATE the sound of whatever listening environment you have the good fortune to be able to capture personally. If you do get an A16 you should really try and get a personal PRIR measurement made at some wonderful listening environment, either private or retail. That's the holy grail.
I have never done anything to tweak the original AIX PRIRs I obtained back in June 2009 through any of the new adjusments now possible with the A16. I consider those tools more for adjusting manually-created or borrowed PRIRs, or PRIRs created from 1 or 2 speakers, etc., rather than for manipulating personal captures of a genuine physical multi-speaker environment. The idea was to DUPLICATE how that room sounded to your ears/brain, not to try and produce a "best possible theoretical".
And of course, the better the headphones/amp you have, the better will the reproduced sound be through PRIR/HPEQ. It has to be better and more accurate and realistic, because the playback equipment itself is superior. I also use an external Audio-DG NFB9 DAC fed optically from the A8/A16 and feeding XLR to my Stax amps. I do believe that optional arrangement provides improved sound over the built-in DAC/amp inside the A8/A16. Not that the built-in hardware is bad, but I think the external DAC/amp just sounds glorious.
Again, I feel the wide open sound of the Stax SR-009/SRM-t007tII to be simply remarkable. Listening to the multi-channel audio track of a modern movie, it's really like it was being shown on the big screen at the front of that AIX studio room and I was sitting there. It's just that transparent, that realistic, and that much the sensation of actually hearing properly directional sound coming from around you where it should be coming from, like it would in a movie theater. Transparently.
I am still using the original 5.1/7/1 PRIR's captures at AIX in 2009. I have not been able to arrange for a current genuine Atmos setup to have a personal 9.1.6 PRIR. Maybe someday I'll get lucky. In the meantime I've just manually constructed a new 9.1.6 by adding the missing speakers from the A16-provided Surrey room, coupled with either the 5.1 or 7.1 AIX ear-level speakers, and it's perfectly fine.
I just love Stax electrostats.