# Multichannel --- ## Overview As of version 1.3, Roon supports multichannel files, signal processing, and playback, of up to eight channels per device. The following file formats are supported: - FLAC - WAV - DSF - DFF - AIFF - ALAC - AAC Multichannel output can be accomplished with: - Locally connected audio devices connected to Roon, Roon Bridge, or Roon Server using - ASIO - ALSA - CoreAudio (recommendation: use ASIO if possible) - WASAPI (recommendation: use ASIO if possible) - Roon Ready devices that support multi-channel playback - 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, this is the most important setting. <img src='http://roon-kb.s3.amazonaws.com/90cdce3e-7338-49df-a59a-35b0e3de0a7b.png'/> The meaning of these layouts is: - **2.0**: L R - **5.1**: L R C LFE SL SR - **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 <img src='http://roon-kb.s3.amazonaws.com/dfb7a203-9168-4a62-b095-5e2ff229b37f.png'/> Roon 1.3 Build 242 contained a change to our default stereo/mono playback behavior when talking to multi-channel devices. Previously, the full channel layout was always sent, with silence sent to unused channels. Now, stereo/mono content is sent using the “2.0” layout, and only multi-channel content uses the selected layout. This setting allows users to revert to the old behavior if desired, but we expect that the default will work for the great majority of use cases. ### Multichannel Mixing Strategy <img src='http://roon-kb.s3.amazonaws.com/497b6b96-77ac-4ab6-81cc-ffd19d81e1fb.png'/> 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. <img src='http://roon-kb.s3.amazonaws.com/fafe2850-d6ef-4bdd-8d97-441ec1dcba01.png'/> ## 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: - 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. - 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. As with anything else, if substantial demand for more comprehensive surround sound processing arises, we will consider expanding our support. Come drop us a line on [our community site](https://community.roonlabs.com/) if you have thoughts about this. ## 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.
Page last changed Mon Dec 04 2017