How to get Dolby Atmos 9.2.6 from the Denon AVR-X8500H\nThe X8500H supports only 7.2.6 or 9.2.4 Atmos layouts and you can’t combine front wide speakers with 6 height speakers. However, it would in theory be possible to do a near perfect 9.4.6 if you had enough money and time.\nWhat you will need:\n\nTwo Denon AVR-X8500H’s (you can afford that right?)\n9 ear level speakers, 6 height speakers and 2-4 subs\nDual HDMI output primary source device like a UHD player\nSingle Board Computer (Raspberry Pi or similar)\nLots of HDMI, speaker and RCA cables\n\nGetting things connected:\n\nPrimary 8500 is first setup pretty much as you normally would except you only connect Front, Center, Front Wides, Surrounds, Top Front (or front height) and 1-2 Subs.\nSecondary 8500 you only connect one HDMI in to blu-ray from the audio only output of your UHD player. All your other sources stay in the Primary AVR. Connect just Surround Back, Top Middle and Top Rear ( or rear height) speakers. You can also connect 1-2 Rear Subs especially if the rear\/height speakers are not full range.\nUse 6 RCA-RCA cables to connect pre-outs for Surround back, Height 2 and Height 3 to 7.1 channel inputs (Surround back, Fronts, Surround) on Secondary. (Note there are no pre inputs for heights but we can use front\/surround inputs and remap the channels later)\nSet your UHD player to output audio from its primary output when audio only port is in use which defaults to video only by default normally\nConnect both units to your network and connect your Single Board Computer as well\n\n\nYour have now done the physical setup so now for the fiddly parts:\n\nSet the Secondary AVR to a 7Channel in and turn off all processing so it acts like a straight amplifier with a fixed volume. Use custom amp assign to redirect front\/surround to the height speaker terminals\nRun speaker\/room calibration on the Primary AVR making sure all channels are working and level matched fine.\nUse a computer to query the setting of the secondary AVR over it’s telnet\/web interface to capture the state of the unit for later use\nSet the Secondary AVR to Blu-Ray input and reset amp assignment for the heights to normal and do a speaker\/room calibration for just the 6 speakers that are attached. \nSet Primary AVR to 9.2.4 (with Top Front\/Top Middle) and Secondary to 7.2.6 mode and match the volume level number of both units.\nPlay back an Atmos track from your Blu-ray player and you will have 9.2.6!!!!!!!!! Just don’t try to adjust volume or change any inputs!\nCapture the state of Secondary AVR as before from your computer\nNow you have to write some code for your Single Board Computer. It has to read the state of the Primary AVR constantly and if it is set to Blu-Ray input it will update the settings on the Secondary to Blu-Ray and apply the second set of settings you recorded. It will also copy the volume and several sound mode settings over to the secondary unit so that when you volume up\/down etc it effects both units after a small delay.\nWhen the input changes from Blu-Ray to anything else it instead applies the initial settings you recorded which puts the Secondary unit into 7Channel in analog mode and it acts as a power amplifier only.\nSit back and enjoy the only 9.2.6 home system in the world!\n\nOther things to consider:\n\nNeed to work out how to trigger the secondary unit and single board computer to power on when the Primary AVR powers on\nYou could try and get 9.4.6 by connecting 2 subs to each unit but the rear subs may only work with the Blu-Ray source. Also the sub levels will need to drop down a few DB to account for the higher SPL of 4 subs running.\nYou can support more than just one input device if each device has double HDMI outputs and you adjust the control program. You can use a HDMI splitting device to make a single HDMI source work.\n\nHow Does it even work:\nIt works by feeding identical audio signals to these two AVR’s with one handling front wide and the other handling additional rear height speakers. The addition of front wides takes away some of the audio from the adjacent speakers when rendering Atmos object based audio and the same thing happens with the additional rear height speakers on the secondary unit. By having one unit handle the speakers surrounding the front wides and the other handle the speakers surrounding the rear height channel this means when you combine the two halves they should sound pretty good. The only downside is any object based audio that comes from the sides and passes overhead as the mix between the side surround speakers and the top middle speakers which are handled by separate units may not be perfect with sounds from some angles being over emphasized a little.