I have some questions, and a few remarks.
Most HRTF's are captured at 1024 data points per ear (2048)
Does that mean you measure the HRTF for 1024 directions, and that for each ear? For the moment I assume that is what it means.
By the way: what is the maximum angle between 2 adjacent points in that case?
The Smyth is capturing 16per ear. (max 32).
Actually if it measures 16 speakers at 5 measurement points (5 lookangles to interpolate between for headtracking/derotating), that would be 80 per ear, 160 total.
Also for one individual pair (one speaker, one lookangle, for the 2 ears) beware that in fact that for that specific lookangle the full HRTF (all directions, an infinite number) is respected: reflexions and reverberations from any direction are captured including the HRTF filtering they underwent. This holds for all the speakers, and all the measurement points. So when during the simulation you look for example straight forward (the zero degree measurement point), at that moment the simulation of all the speakers and the room is "accurate" in the sense that it is not in anyway compromised by lack of having a 1024/2048 point HRTF. Only at the moment that you move your head inbetween the measurement points and the Realiser starts interpolating then there could be (and probably will be) inaccuracy in that same sense.
The Smyth réaliser is capturing the BRIR.
A little detail: When you do a personal measurement with the Realiser you are actually capturing a PRIR (Personalised Room Impulse Response), not a BRIR (although it would be a BRIR for someone else). Indeed you can not extract the personal HRTF from that, but the personal HRTF is fully respected in the sense that I descibed above.
Note that in the approach of capturing an isolated HRIR and combining that with an isolated room response later, to make that "accurate" you should somehow make sure that all refexions and reverberations undergo the proper HRTF filtering belonging to the many different directions they are approaching the ears from. Is this incorporated in what you desribe in the following quote?
You add a room to the tail of an anechoic HRTF. Then convolve with coordinates of the intended speaker location.