I'm going to make the point that this SDA technology is bogus and can not be a contribution to realistic audio. In my view it is pure nonsense, and here is why.
I don't doubt it can produce an artificially wide soundstage by exaggerating left and right information.
Now in a concert hall a trumpet say on the right of the orchestra will be heard by both ears. We listen with left right crosstalk.
A flute say in the center will be heard equally by both ears. So let us focus on the center stage.
Now play this through an SDA speaker, and the flute should play equally in both speakers. Now let is play it through this SDA contraption, and an out of phase signal is now fed equally to both those speakers. This has to result in reduction of the central image at the expense of artificial enhancement of the left and right information.
There is no way that this can correctly balance a good recording of a symphony orchestra and choir.
I did hear the previous generation of SDA speakers and thought they were just plain awful, providing very unnatural reproduction.
I have not heard the new SDA efforts, but the whole premise makes absolutely no sense to me, and smacks of extreme gimmickry.
The real villains here though, are recording engineers that do not know their craft. I'm talking about peppering a multitude of microphones all over the place, where two, or at the most three would be a huge improvement.
This has been really brought home to me of late. The BBC have on iPlayer the Easter service form King's College. The sound was outstanding, with everything in acoustic perspective. The sound stage way bigger than the room and the organ in the far distance.
No mics to be seen, except on one shot. To may surprise there were three
large diaphragm Coles ribbon mics, spaced at a distance. Now these mics were originally manufactured by Standard Telephones and Cables back in the 1950s, and much loved by the BBC. After STD went out of business, these mics have been produced by Coles since.
The sound stage produced was absolutely incredible, and the organ reproduction most realistic, with a phenomenal bass response.
Producing a realistic soundstage is 50/50 microphone technique and speakers, and not nonsensical gimmicks like SDA.
Here is another example of the benefits of minimalist miking.
I have referred before to the Scott Brothers DUO. They have continued to entertain through this pandemic. Tom uses pure Blumlein intensity technique, with a single crossed pair at a distance.
This recent recording which is fantastic, comes from Ripon Cathedral.
This includes Jonathan's transcription of the Saint Saens organ symphony, where he plays the organ, piano and orchestral parts all by himself! He uses pedals and all four keyboards at once, using thumbs down.
This recording really can demonstrate how effective the Dolby upmixer is with a phase coherent recording. This organ has three widely spaced divisions. There are large divisions right ahead, on the left at the side is a large pedal division and some powerful reeds. On the right side is is division containing both flutes and reeds.
In my room this all sounds best in the third row. The main organ is the distant and the powerful pedal reads blasting hard left. The more delicate division from the right.
Fortunately my surrounds are potent, and only 12 db down at 25 Hz. Each surround speaker powered by 250 watts. The whole effect is incredibly realistic, and you are literally placed at the four manual console by Jonathan Scott.
