Refactor sound card config

hosts/odyssey/audio.nix

@@ -0,0 +1,45 @@
+{ config, pkgs, ... }:
+let
+  snd-usb-audio-module = pkgs.callPackage ./snd-usb-audio.nix {
+    kernel = config.boot.kernelPackages.kernel;
+  };
+  upmixConfig = ''
+    stream.properties = {
+      channelmix.upmix = true
+      channelmix.upmix-method = psd
+    }
+  '';
+in {
+  boot.extraModulePackages = [
+    (snd-usb-audio-module.overrideAttrs (_: {
+      patches = [ ./0001-Update-device-ID-for-PreSonus-1824c.patch ];
+    }))
+  ];
+
+  environment.etc = {
+    "pipewire/pipewire.conf.d/surround.conf".text = ''
+      context.modules = [
+        {
+          name = libpipewire-module-loopback
+          args = {
+            node.description = "Genelec 4.1 Surround"
+            capture.props = {
+              node.name = "Genelec_Speakers"
+              media.class = "Audio/Sink"
+              audio.position = [ FL FR SL SR LFE ]
+            }
+            playback.props = {
+              node.name = "playback.Genelec_Speakers"
+              audio.position = [ AUX0 AUX1 AUX3 AUX4 AUX5 ]
+              target.object = "alsa_output.usb-PreSonus_Studio_1824c_SC4E21110775-00.multichannel-output"
+              stream.dont-remix = true
+              node.passive = true
+            }
+          }
+        }
+      ]
+    '';
+    "pipewire/pipewire-pulse.conf.d/40-upmix.conf".text = upmixConfig;
+    "pipewire/client-rt.conf.d/40-upmix.conf".text = upmixConfig;
+  };
+ } 

hosts/odyssey/default.nix

@@ -4,6 +4,7 @@ with lib.my;
 {
   imports = [
     ./hardware-configuration.nix
+    ./audio.nix
     ../desktop.nix
   ];
 
@@ -16,32 +17,8 @@ with lib.my;
 
   networking.hostName = "odyssey";
   networking.hostId = "c5e68d78";
-
   networking.networkmanager.enable = true;
 
-  environment.etc."pipewire/pipewire.conf.d/surround.conf".text = ''
-    context.modules = [
-      {
-        name = libpipewire-module-loopback
-        args = {
-          node.description = "1824c Surround"
-          capture.props = {
-            node.name = "1824c_Speakers"
-            media.class = "Audio/Sink"
-            audio.position = [ FL FR SL SR LFE ]
-          }
-          playback.props = {
-            node.name = "playback.1824c_Speakers"
-            audio.position = [ AUX0 AUX1 AUX3 AUX4 AUX5 ]
-            target.object = "alsa_output.usb-PreSonus_Studio_1824c_SC4E21110775-00.multichannel-output"
-            stream.dont-remix = true
-            node.passive = true
-          }
-        }
-      }
-    ]
-  '';
-
   nix.package = pkgs.nixFlakes;
   nix.extraOptions = ''
     experimental-features = nix-command flakes

hosts/odyssey/hardware-configuration.nix

@@ -1,10 +1,6 @@
 { config, lib, pkgs, modulesPath, ... }:
 
-let
+{
-  snd-usb-audio-module = pkgs.callPackage ./snd-usb-audio.nix {
-    kernel = config.boot.kernelPackages.kernel;
-  };
-in {
   imports = [
     (modulesPath + "/installer/scan/not-detected.nix")
   ];
@@ -13,11 +9,6 @@ in {
   boot.initrd.kernelModules = [ ];
   boot.kernelModules = [ "kvm-intel" ];
   boot.kernelPackages = pkgs.linuxPackages;
-  boot.extraModulePackages = [
-    (snd-usb-audio-module.overrideAttrs (_: {
-      patches = [ ./0001-Update-device-ID-for-PreSonus-1824c.patch ];
-    }))
-  ];
   boot.supportedFilesystems = [ "ntfs" ];
   boot.binfmt.emulatedSystems = [ "aarch64-linux" ];