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HDMI Maximum Audio Channels (9.1, 11.1 etc.)?

17K views 27 replies 9 participants last post by  Heavenly71 
#1 ·
I am going to buy a Marantz SR7009 and need to know if the extra channels show up in Windows when connected via HDMI to a GeForce GPU. If so, what configuration do they show up as (front wide, ceiling, etc). My current SR5008 shows 7.1 channels (all surround) but that's also the limit of the receiver.
 
#2 ·
HDMI 1.4 is limited to 8 channels, if you want more you need to invest into an entire system with HDMI 2.0 which allows up to 32 channels, however the only GPUs available with HDMI 2.0 are the new GeForce 970 and 980, and I couldn't tell you if they actually support more then 8 audio channels.
 
#3 · (Edited)
This is only true if the PC is doing the decoding and outputting as PCM audio over a single HDMI connection. If you bitstream the audio to your receiver over HDMI then you can pass far more than 8 channels even on older versions of HDMI. This is how an HDMI 1.3/1.4 blu-ray player can pass an Atmos soundtrack that can ultimately support up to 34 discrete channels.

Alternatively, if you use a MIDI, USB, Thunderbolt, or similar interface to feed the audio to a device which can convert the digital signal to analog then it can be output as a separate analog cable for as many channels as your device supports. Some support 16 channels. Some support 32, 64, 96, or even 128 discrete channels. In your case, a 16 channel model would be more than sufficient. You would just need to set the PC up to use matrix processing to output the soundtrack as 9.1 or 11.1 and then make the 10 or 12 analog connections from the device to your receiver/pre-pro. Note that the Marantz SR 7009 (and most AVR's/pre-pro's for that matter) only have enough analog inputs for 7.1, so you would still be limited to 8 channels if you want to use the AVR. If you want more than 8 channels using the analog method then you will have to look into using the PC as a pre-pro (volume, eq, etc.) and buy enough power amps to drive as many channels as you want.

P.S. Other than Atmos and Auro soundtracks, there is very little content that is actually encoded with more than 8 discrete channels, so the benefits of going with a PC that can output more than 8 channels are somewhat dubious at this point in time.
 
#4 · (Edited)
To put it another way, explicitly answering your question:

No, the receiver's additional channels are not seen by the computer. To use them directly, you have to bitstream a soundtrack which does: either an Atmos soundtrack or one that was recorded using DTS Neo:X. To bitstream an Atmos soundtrack, you need up-to-date media player software (less than a month old). Older ones can't bitstream Atmos. Bitstreaming the handful of movies encoded using DTS Neo:X should work with older software.

Edited to add: I'm ignoring Auro because the SR7009 can't decode it. Yet.
 
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#5 ·
I can upgrade my GPU as well. Now I need to know if a GTX 980 will detect the additional channels with HDMI 2.0.

I want to use it for games as well. I need to know if and how the speaker layout will be seen within Windows. Does it even support height or front wide speakers which have been around for years, let alone ceiling speakers?

I currently don't bitstream since it introduces unnecessary seeking lag and I don't tolerate anything short of instantaneous response when using a PC. I prefer instantaneous response to the imperceptible impurities and reference volume level change introduced by decoding and mixing it with the PC's PCM output stream. However I'm pretty sure that there will be some reason that Atmos won't work without bitstreaming even if all the extra channels are visible over HDMI.

Can someone confirm if a GTX 980 will see all the extra channels on a HDMI 2.0 capable receiver?
 
#12 ·
If your game uses OpenAL to render audio you can use Rapture3D to output more than 8 channels. Rapture3D Advanced supports up to 128 channels and you can custom map each speaker position in a 3D space. If you replace their default OpenAL driver on your system with Rapture3D you can use it in ANY application that uses OpenAL. The output uses ASIO so you can simply get an interface with as many channels as you need and it will work with no lag.

I actually emailed with their support once and found out their developer uses 21 Genelec 8020s speakers and 7060 subwoofers.

Now the bad news: It costs £599 (955USD :eek: )

http://www.blueripplesound.com/products/rapture-3d-advanced
 
#13 · (Edited)
If your game uses OpenAL to render audio you can use Rapture3D to output more than 8 channels. Rapture3D Advanced supports up to 128 channels and you can custom map each speaker position in a 3D space. If you replace their default OpenAL driver on your system with Rapture3D you can use it in ANY application that uses OpenAL. The output uses ASIO so you can simply get an interface with as many channels as you need and it will work with no lag.

I actually emailed with their support once and found out their developer uses 21 Genelec 8020s speakers and 7060 subwoofers.

Now the bad news: It costs £599 (955USD :eek: )

http://www.blueripplesound.com/products/rapture-3d-advanced
There are a whole bunch of issues which make that impossible. I ultimately need to send the audio to an AVR digitally so that room correction can be applied. It won't work for analogue inputs.


There are no ASIO sound cards which can output more than 8 channels to HDMI.
There are no more currently supported sound cards which do any kind of HDMI.
I'll have to use some complex chain of ASIO, AES/EBU, SDI or HDMI embedders to finally get the channels to the currently non-existent > 8 channel input AVR.
Room correction is mandatory. Even Dirac has no > 8 channel version for consumers.
It needs to work for xAudio2 & OpenAL & leagy DirectSound games.
It needs to work on the Windows desktop universally and with WASAPI players.


The only workable solution is a HDMI 2.0 compliant AVR and GPU which accepts > 8 channels, whenever they are invented.
 
#14 ·
If I look at your requirements, you could do something like this:
Source PC with PCIE MADI card, do all the processing and mixing in the DSP of the card, then MADI to analog converters to a stack of power amps.

http://www.rme-audio.de/en_products_hdspe_madi_fx.php
http://www.rme-audio.de/en_products_m32da.php

It will cost you several thousand dollars though and you need to setup all the processing yourself.

MiniDSP makes external DSP's with Dirac now: http://www.minidsp.com/products/dirac-series/product-line-summary
You could get an interface with allot of AES/EBU outputs and a bunch of Dirac MiniDSP's. They only have stereo models so you would still need a big stack of them but it is an easier solution.
 
#15 ·
If I look at your requirements, you could do something like this:
Source PC with PCIE MADI card, do all the processing and mixing in the DSP of the card, then MADI to analog converters to a stack of power amps.

http://www.rme-audio.de/en_products_hdspe_madi_fx.php
http://www.rme-audio.de/en_products_m32da.php

It will cost you several thousand dollars though and you need to setup all the processing yourself.

MiniDSP makes external DSP's with Dirac now: http://www.minidsp.com/products/dirac-series/product-line-summary
You could get an interface with allot of AES/EBU outputs and a bunch of Dirac MiniDSP's. They only have stereo models so you would still need a big stack of them but it is an easier solution.
These professional interfaces don't show up as standard playback devices in Windows at all. They can only be use in DAW software that supports them.


Either way I've learned that all standard software and games have a hard limit of 8 channels in Windows. HDMI solves that for now. Until the entire PC and HDMI device stack are upgraded to support > 8 channels over HDMI 2.0 there is no solution.
 
#17 ·
I just investigated into this 2 year old topic again. My goal is to transmit 11.1 (or 9.1) channels of LPCM from my PC to a receiver via HDMI. Result: There is no way. If I'm wrong please let me know.

Even top-of-the-line receivers from any brand (I checked Onkyo, Denon, Yamaha and Sony) can only extract 8 channels of LPCM sound from HDMI. Despite the fact they all have HDMI2, which supports up to 32 channels. And on the PC side I'm currently looking at Windows 10 (Anniversary Update) in its speaker configuration dialog it only supports up to 7.1 channels. But that's probably only a software issue that will be fixed by Microsoft.

I know there are main-amps with 9 or 11 analog inputs. But it's a hassle to wire this up, and also you need an expensive sound card on the PC side (is there even one? – I didn't investigate)

I also know you can bitstream Dolby Atmos from PC to receiver via HDMI which can have up to 7.1.4 (=11) channels. But this doesn't make any sense for games; it would only degrade quality and introduce lag by encoding LPCM source material to Atmos and back…
 
#18 ·
I just investigated into this 2 year old topic again. My goal is to transmit 11.1 (or 9.1) channels of LPCM from my PC to a receiver via HDMI. Result: There is no way. If I'm wrong please let me know.
Unfortunately, you are correct. So far as I know, none of the consumer entertainment manufacturers have implemented that feature of HDMI v2.0.

As best I can determine, you'll have to use line-level analog outputs if you need that many separate audio channels.

Here are some examples of professional multichannel interfaces. I'm sure there must be others. http://www.soundonsound.com/reviews/multi-channel-audio-interfaces
 
#22 · (Edited)
It seems that consumer Atmos decoding is not object-based at all. Everything from 7.1.4 to 24.1.10 is pre-rendered as a "spatially-encoded digital channel" - it's not clear how this allows the receiver to position it in different speaker layouts. The base 7.1-channel layer is pre-rendered as TrueHD for backwards compatibility.

For games, this means the Atmos renderer can be used in the engine for positioning for any number of channels.
 
#24 ·
Windows now supports 7.1.4 channels natively, in addition to Atmos encoding. If an audio device driver exposed these channels (like a sound card or HDMI), PCM output should be possible. I still don't know if any AVR accepts 7.1.4 over HDMI or if any GPU driver supports it.
 
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