My Nuc is running Roon Rock and is connected to my processor over HDMI.
In the device setup I can choose channel layout 2.0 or 5.1 or 7.1.
Then there is a choice for sending stereo/mono as 7.1 (when channel layout 7.1) is selected.
Further multichannel mixing can be set to downmix as needed or channel mapping only.
The question is this: can I arrange that Roon only decodes channels and does not change what goes to which channel (no upmixing, optimizing, redistribution etc.) So: my processor and not Roon would be the only one to assign sound to a channel.
To clarify: I don’t even want to indicate how many channels my processor has (2.0, 5.1 or 7.1).
As shown in the Roon signal path after selecting 7.1 as channel layout, Roon always upmixes 5.1 to 7.1. Only stereo/mono is not upmixed when that slider is at “no”.
What would make sense to me is a selection to just forward the channels as decoded and not do any channel redistribution, sound to channel assignment or upmixing.
Edited to add screenshots and a clarification. Playing a test track downloaded from Linn so there is a good reference track.
I may be wrong - I don’t use multi-channel audio - but to me, the 5.1 → 7.1 channel mapping indication in the signal path does not imply upmixing.
It just tells me that Roon has chosen which of the eight output (hdmi) channels to send each of the six input channels leaving 2 hdmi channels carrying no audio.
There is indeed no upmix involved. In the settings you can set the amount of channels the output device is capable of. Downmix is possible but is only nessesarry if your setup is less than 7.1 and the amp cannot handle Downmx by itself. Usually you only have to use it if you play Surround files to a stereo player.
If you set the “Send stereo/mono content as 7.1” then all channels will be used,
The reason for the channel mapping layout in the signal path is because it then uses the Surround layout. However, I never understood why the Signal path channel mapping shows up at all as actually no channelmapping is involved when 5.1 is played to 7.1. When you play a Stereo file you will not see this.
I’ve used the multi-channel setup with the HDMI connection from the NUC/ROCK to Denon 8500H since 2019. I use the 7.1 channel layout only so Roon adds the option to Swap rear and surround channels. I have swapped the rears to the sides so I can hear the back channels while setting in a high backed recliner. I have the Denon set to use the Dolby Surround processor to simulate multi-channel for Stereo files.
I was under the impression roon was doing what you’re asking. I thought Roon was playing the music files, Stereo or Multi-channel, as recorded with this setup and not doing any channel mapping, and Multichannel mixing (downmix as needed) only occurred if the source file had more channels than the Channel layout specified. I’m deaf on the right side so perhaps I just can’t tell the difference.
Haven’t checked the signal path recently, don’t recall the Channel Mapping item showing up. Need to check that out.
The thing is: If you have set up a 7.1 layout in Roon, it will always send any Surround files in that specific channel Layout, regardless of the number of channels (except Stereo as I mentioned before). For instance: Roon delivers a 5.1 file in the layout you have chosen. If this is 7.1, then the Receiver will get a 5.1 fiile, but “sees” it as a 7.1 channel layout. You can see this on your Denon (I have a AVC-A110, so the Software from Denon is quite the same than your 8500H). But that is something I don’t want. I would rather see the exact amount of Channels I am listening to, which happens when I play DvA, SACD’s, Blu-Rays etc via my Oppo.
Another side-effect of this is that your receiver is not able to upmix files with lower Surround channels to Dolby Surround or any other Surroundmode your receiver provides. I have tried this often enough.
JRiver does a better Job: You can set it up either to a specific Channel-layout or just leave it to “All channels”, which I have done. When I play the same Surround files through JRiver the Receiver then shows the actual Channels form the file and you are able to play arround with your AVR upmixes.
Thanks all.
This is really helpful, including the text in the link.
My understanding: Roon takes the number of channels at the processor from the settings as in the screenshot above for granted as the number of channels and doesn’t ask the processor.
When mapping it may
either add silent channels if there are more channels indicated to be in the processor than in the audio track
drop channels if there are less channels indicated for the processor than there are in the audio track AND channel mapping only is selected. When downmix as needed is on, no channels are dropped.
upmix 2.0 to 5.1 or 7.1 (“Toggling this setting allows users to force surround playback for stereo content if desired, but we expect that the default behavior will offer the best results for the great majority of use cases.”). Not sure if this is what they want to say.
It is unclear if Roon packs the info about the amount of channels that it is sending to the endpoint/processor.
So the confusing indication indeed is that this mapping shows up in the signal path, where it does not for 2.0. Also if 2.0 does not need to be output as 7.1, why would 5.1 be?
I do agree with Frank: if JRiver can make the processor to see the actual channels from the file, then why can’t Roon. Is there a feature request for this which I can up?
I am actually unsure what my processor does with any silent input channels. Not sure if the number of channels sent by Roon is included in the data. Say the processor is told by Roon that there are say 7.1 channels and then receives 2 silent channels when the audio track is in 5.1.
I can’t really see what channels are received on my processor, regretfully.
I have a 4.1 configuration without a center. I think I read from the info above that the center channel is not dropped by Roon when the settings in Roon are 5.1 or 7.1. This is because Roon looks at the settings and not at the real situation at the processor or speakers.
When 2.0 and “Channel mapping only” are selected it might, just as the SL,SR,RL and RR channels if present in the audio track.
Moreover: when the audio track in an object based format, the processor can place the objects in the desired position, hence how it is distributed over the speaker channels is decided by the processor based on speaker locations and desired object locations (the way Dolby intended that). But there I get to another question: does it get object based input over HDMI as well as over Raat?
