Virtual surround sound

[JustCauseWhyNot]

How would I emulate

virtual surround

context.modules = [
    { name = libpipewire-module-filter-chain
        flags = [ nofail ]
        args = {
            node.description = "Virtual Surround Sink"
            media.name       = "Virtual Surround Sink"
            filter.graph = {
                nodes = [
                    # duplicate inputs
                    { type = builtin label = copy name = copyFL  }
                    { type = builtin label = copy name = copyFR  }
                    { type = builtin label = copy name = copyFC  }
                    { type = builtin label = copy name = copyRL  }
                    { type = builtin label = copy name = copyRR  }
                    { type = builtin label = copy name = copySL  }
                    { type = builtin label = copy name = copySR  }
                    { type = builtin label = copy name = copyLFE }

                    # apply hrir - HeSuVi 14-channel WAV (not the *-.wav variants) (note: */44/* in HeSuVi are the same, but resampled to 44100)
                    { type = builtin label = convolver name = convFL_L config = { filename = "/etc/pipewire/pipewire.conf.d/atmos.wav" channel =  0 } }
                    { type = builtin label = convolver name = convFL_R config = { filename = "/etc/pipewire/pipewire.conf.d/atmos.wav" channel =  1 } }
                    { type = builtin label = convolver name = convSL_L config = { filename = "/etc/pipewire/pipewire.conf.d/atmos.wav" channel =  2 } }
                    { type = builtin label = convolver name = convSL_R config = { filename = "/etc/pipewire/pipewire.conf.d/atmos.wav" channel =  3 } }
                    { type = builtin label = convolver name = convRL_L config = { filename = "/etc/pipewire/pipewire.conf.d/atmos.wav" channel =  4 } }
                    { type = builtin label = convolver name = convRL_R config = { filename = "/etc/pipewire/pipewire.conf.d/atmos.wav" channel =  5 } }
                    { type = builtin label = convolver name = convFC_L config = { filename = "/etc/pipewire/pipewire.conf.d/atmos.wav" channel =  6 } }
                    { type = builtin label = convolver name = convFR_R config = { filename = "/etc/pipewire/pipewire.conf.d/atmos.wav" channel =  7 } }
                    { type = builtin label = convolver name = convFR_L config = { filename = "/etc/pipewire/pipewire.conf.d/atmos.wav" channel =  8 } }
                    { type = builtin label = convolver name = convSR_R config = { filename = "/etc/pipewire/pipewire.conf.d/atmos.wav" channel =  9 } }
                    { type = builtin label = convolver name = convSR_L config = { filename = "/etc/pipewire/pipewire.conf.d/atmos.wav" channel = 10 } }
                    { type = builtin label = convolver name = convRR_R config = { filename = "/etc/pipewire/pipewire.conf.d/atmos.wav" channel = 11 } }
                    { type = builtin label = convolver name = convRR_L config = { filename = "/etc/pipewire/pipewire.conf.d/atmos.wav" channel = 12 } }
                    { type = builtin label = convolver name = convFC_R config = { filename = "/etc/pipewire/pipewire.conf.d/atmos.wav" channel = 13 } }

                    # treat LFE as FC
                    { type = builtin label = convolver name = convLFE_L config = { filename = "/etc/pipewire/pipewire.conf.d/atmos.wav" channel =  6 } }
                    { type = builtin label = convolver name = convLFE_R config = { filename = "/etc/pipewire/pipewire.conf.d/atmos.wav" channel = 13 } }

                    # stereo output
                    { type = builtin label = mixer name = mixL }
                    { type = builtin label = mixer name = mixR }
                ]
                links = [
                    # input
                    { output = "copyFL:Out"  input="convFL_L:In"  }
                    { output = "copyFL:Out"  input="convFL_R:In"  }
                    { output = "copySL:Out"  input="convSL_L:In"  }
                    { output = "copySL:Out"  input="convSL_R:In"  }
                    { output = "copyRL:Out"  input="convRL_L:In"  }
                    { output = "copyRL:Out"  input="convRL_R:In"  }
                    { output = "copyFC:Out"  input="convFC_L:In"  }
                    { output = "copyFR:Out"  input="convFR_R:In"  }
                    { output = "copyFR:Out"  input="convFR_L:In"  }
                    { output = "copySR:Out"  input="convSR_R:In"  }
                    { output = "copySR:Out"  input="convSR_L:In"  }
                    { output = "copyRR:Out"  input="convRR_R:In"  }
                    { output = "copyRR:Out"  input="convRR_L:In"  }
                    { output = "copyFC:Out"  input="convFC_R:In"  }
                    { output = "copyLFE:Out" input="convLFE_L:In" }
                    { output = "copyLFE:Out" input="convLFE_R:In" }

                    # output
                    { output = "convFL_L:Out"  input="mixL:In 1" }
                    { output = "convFL_R:Out"  input="mixR:In 1" }
                    { output = "convSL_L:Out"  input="mixL:In 2" }
                    { output = "convSL_R:Out"  input="mixR:In 2" }
                    { output = "convRL_L:Out"  input="mixL:In 3" }
                    { output = "convRL_R:Out"  input="mixR:In 3" }
                    { output = "convFC_L:Out"  input="mixL:In 4" }
                    { output = "convFC_R:Out"  input="mixR:In 4" }
                    { output = "convFR_R:Out"  input="mixR:In 5" }
                    { output = "convFR_L:Out"  input="mixL:In 5" }
                    { output = "convSR_R:Out"  input="mixR:In 6" }
                    { output = "convSR_L:Out"  input="mixL:In 6" }
                    { output = "convRR_R:Out"  input="mixR:In 7" }
                    { output = "convRR_L:Out"  input="mixL:In 7" }
                    { output = "convLFE_R:Out" input="mixR:In 8" }
                    { output = "convLFE_L:Out" input="mixL:In 8" }
                ]
                inputs  = [ "copyFL:In" "copyFR:In" "copyFC:In" "copyLFE:In" "copyRL:In" "copyRR:In", "copySL:In", "copySR:In" ]
                outputs = [ "mixL:Out" "mixR:Out" ]
            }
            capture.props = {
                node.name      = "effect_input.virtual-surround-7.1-hesuvi"
                media.class    = Audio/Sink
                audio.channels = 8
                audio.position = [ FL FR FC LFE RL RR SL SR ]
            }
            playback.props = {
                node.name      = "effect_output.virtual-surround-7.1-hesuvi"
                node.passive   = true
                audio.channels = 2
                audio.position = [ FL FR ]
            }
        }
    }
]

in easyeffects?

[wwmm]

At the moment there is no way to do virtual surround in EasyEffects. At least not the way I understand it. As our pipeline is stereo we can not take a surround signal and applying the hrir to transform it in a stereo signal that emulates the surround effect.

[JustCauseWhyNot]

Unfortunate to hear, but I greatly appreciate the answer. It'll save me a lot of time.

Thank you.

[p-chan5]

You can try using my presets and enabling the second or third equalizer, both of which will emulate a Dolby Atmos effect, on a stereo signal.

Although if your architecture supports 5.1 or 7.1 surround you can also use Carla and apply processing to each channel.

I don't really know how these things work on a hardware level, but both tools (EasyEffects/Carla) have worked well for me so far :)