How to get Dolby Atmos 9.2.6 from the Denon AVR-X8500H



Full Audioholic
97 1
How to get Dolby Atmos 9.2.6 from the Denon AVR-X8500H
The 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.
What you will need:
  1. Two Denon AVR-X8500H’s (you can afford that right?)
  2. 9 ear level speakers, 6 height speakers and 2-4 subs
  3. Dual HDMI output primary source device like a UHD player
  4. Single Board Computer (Raspberry Pi or similar)
  5. Lots of HDMI, speaker and RCA cables
Getting things connected:
  1. Primary 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.
  2. Secondary 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.
  3. Use 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)
  4. Set 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
  5. Connect both units to your network and connect your Single Board Computer as well

Your have now done the physical setup so now for the fiddly parts:
  1. Set 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
  2. Run speaker/room calibration on the Primary AVR making sure all channels are working and level matched fine.
  3. Use 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
  4. Set 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.
  5. Set 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.
  6. Play 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!
  7. Capture the state of Secondary AVR as before from your computer
  8. Now 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.
  9. When 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.
  10. Sit back and enjoy the only 9.2.6 home system in the world!
Other things to consider:
  1. Need to work out how to trigger the secondary unit and single board computer to power on when the Primary AVR powers on
  2. You 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.
  3. You 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.
How Does it even work:
It 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.


Full Audioholic
97 1
With at street price around $12000, this would provide enough features for discrete audio up to 9.x.6. Granted you have to pay additional for licensing fees for Auro3d. But if your doing this many channels most have the room and the money for it.
See my solution just saved you $4000 ;)
And you get two good amplifiers built in as well.

But yeah your right there are a few of these ultra high channel pre amps.

One interesting thing is even these only seem to work well with atmos and dts-x and auto 3d are limited to 11 or whatever channels by the limited upstream firmware. My crazy solution with two x8500h's is also limited like this.


Full Audioholic
97 1
OK, what are software is available to take advantage of the above set up?
For my crazy 2xAVR setup it will work best with any source device that can output atmos which is mainly blu ray and a very limited number of streaming options. If you really wanted 9.2.6 upmixing from stereo or 5.1 sources then it would handle that just fine as well using the Dolby surround upmixer.

The only limitation is you may have to use a single source device and can't use denon built in HEOS or other streaming options as it requires an external hdmi duplicated signal.

Also note that for any other input it falls back to using the second unit as an external amplifier only so you get 7.2.6 or 9.2.4 layout options for all other inputs/sources
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