Expanded the sidewall surrounds into separate array channels.
Rewired the sidewall surrounds so that the extra Onkyo TX SR-875 that is mated with main AVR Marantz SR6012 Dolby Atmos / dtsX via the side stereo surrounds that normally I had wired playing the same sound stereo sidewall signal into three speakers per sidewall. Now I have split them up using the PLIIx movie mode on the extra Onkyo TX SR875 so that the signal is divided up into separate matrix channels that seems to work with better speciousness of the sound panning moving from one speaker to the other.
So the diagram is best way I can channel the sidewall arrays with front furthest wired to Onkyo TX SR-875 front LR outputs.
Middle surrounds wired to side surround outputs.
Back side surround wired to rear back surround output.
Its down to how the mix is created and how the PLIIx moves the sound signals along the sidewalls. It works maybe not like the Dolby Atmos pan-though but it works and I'm starting to like it at cheap cost to do this.
Still experimenting with levels to get them timber matched. I could use, the manual EQ or careful use the Audyssey multeq mic on JBL 8330 to get them adjusted but I rather do it manually but the Onyko manual EQ is rather restricted to 9 bands per each channel. To use separate outboard EQ I would have to use the RCA outputs on the Onkyo TX SR875 and the cost of extra amplifiers but as it is its not all right or wrong it works and again at sensible diy budget cost. I think its best improvement I done to the sidewall surrounds that they can now play differently.
The rear back wall surrounds may get a third Onkyo TX SR-875 but need two more JBL 8330 that would have to be positioned very closely but I don't see the real need to do it If the room was wider maybe I would do it.
With five screen plus the left/right surround, left/rear back surround the four overhead surrounds and the two subs
3.2.2.4.2 - 13 channels or
5.2.2.4.2 - 15 channels and now
5.3.3.4.2 19 channels. Blimey it even does my own head in.
Presently the centre channel output from the Onkyo TX SR-875 is set to OFF so the forward side surrounds have the phantom-centre merged. I could use 9th JBL 8330 or repair my other 5th JBL control 5 and mount that to the ceiling in the middle between the four Atmos/dtsX overheads or leave it as it is or experiment with later on.
I'm listening to sound to see how well it merges with back wall surrounds with repeated playings of Alien Coverant, Dolby Atmos, chapter 20.
I'll rewire the below surrounds back up when I can figure out what decoder to use and which output I want to connect it to. As it is now, sort of excited with it.
The diagram is only showing how I wired the surround arrays. There are other AVR's in the rack to reduce cost for powering the speakers with a few pro amplifiers and other processors in the main room that links all this together.