Multichannel

Overview

Roon supports multichannel files, signal processing, and playback, of up to eight channels per device. The following file formats are supported:

1. FLAC 
   
2. WAV 
   
3. DSF 
   
4. DFF 
   
5. AIFF 
   
6. ALAC 
   
7. AAC 
   

Multichannel output can be accomplished with:

1. Locally connected audio devices connected to Roon, Roon Bridge, or Roon Server using
   
1. ASIO (recommended)
   
2. ALSA
   
3. CoreAudio 
   
4. WASAPI 
   
2. Roon Ready devices that support multi-channel playback
   
3. HQPlayer 
   

Configuring your Device for Multichannel Playback

Before Roon will send more than two channels of audio to your device, some configuration is necessary. This is accomplished on the "Device Setup" screen, accessible from Settings->Audio.

Channel Layout

If you have a multi-channel device, properly setting up your "Channel Layout" is the most important step. The following screenshots walk you through this process. 

Start by clicking the speaker icon in the bottom right corner, and then the gear icon from the menu that appears

Next, you'll need to select "Device Setup" from the pop-out menu that appears

Finally, click "Show advanced" and then scroll to the bottom to find the Channel layout setting

The meaning of these layouts is:

1. 2.0: L R
   
2. 5.1: L R C LFE SL SR
   
3. 7.1: L R C LFE RL RR SL SR
   

L = Left, R = Right, C = Center, LFE = Low Freq Effects, RL = Rear Left, RR = Rear Right, SL = Surround Left, SR = Surround Right

If you have 2 speakers, choose 2.0. If you have up to 6, choose 5.1, and if you have 8, choose 7.1. Then make sure they are wired in the right order. If you are using HDMI, you may need to use 7.1 even if you only have 6 speakers--many AV receivers don't work properly with 5.1. Roon Ready devices should present the channels in order specified above. Other devices may do other things. The best way to figure it out is to find some test tones that send audio to one channel at a time and play them back.

Send stereo/mono content as 7.1 or 5.1

 

By default, Roon sends stereo/mono content using the “2.0” layout, and only multi-channel content uses the selected layout. 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.

Multichannel Mixing Strategy

There are two options: "Downmix as Needed" and "Channel Mapping Only". By default, Roon is set up to Downmix content if the content has more channels than the output device--this is the setting we recommend. If you prefer that Roon not perform any downmixing, you should use "Channel Mapping Only". Roon will simply drop any channels that can't be mapped to speakers instead of playing them.

Swap Rear and Surround Channels (Only for 7.1)

Sometimes for compatibility or legacy reasons, a system has the surround and rear channels swapped so that the surround channels come before the rear channels. This setting re-directs the audio streams to compensate.

Channel Mapping

The multi-channel world is a graveyard of false-starts and obsolete technologies, plus a lot of video/movie specific schemes that aren't very relevant in an audio-only environment like Roon. Most musical content produced recently is either in either 2.0, 5.0 or 5.1. There is a small amount of 7.1, too, and a small amount of Quadrophonic content. Compared to these four formats, practically everything else qualifies as exotic in an audio/music context.

Channel mapping for 2.0, 5.0, 5.1, and 7.1 is straightforward, since each larger layout simply adds channels to the previous one. In these cases, Roon matches up the channels from the source material with the channels on the output device and fills any unused channels with silence. Quadrophonic content is handled slightly differently:

1. When playing Quad content to a 5.1 channel layout, the rear channels from the content will be mapped to the corresponding surround channels in the 5.1 layout
   
2. When playing Quad content to a 7.1 channel layout, the RL and RR channels in the Quad content will be mapped onto the RL and RR channels in the 7.1 layout

Other content is handled on a best-effort basis: if channel labels in the content line up with channels in your output channel layout, they are mapped. Un-mappable channels are ignored. One example: Roon never maps content from a "Rear Center" channel.

Downmixing

Roon's downmixing engine supports the most common cases that come up during music playback. - 7.1 → 5.1 - 7.1 → 2.0 - 5.1 → 2.0 - 5.0 → 2.0 The primary objective is to ensure that as much content as possible can be played through stereo zones without ignoring non-subwoofer channels. Other cases will fall back on the Channel Mapping behavior described above.

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