Low latency for sdac

flake.nix

@@ -111,6 +111,7 @@
           ./modules/common/linux
           (common-nix stable)
           inputs.secrets.nixosModules.common
+          inputs.nix-gaming.nixosModules.pipewireLowLatency
         ];
       };
 

modules/common/linux/default.nix

@@ -153,6 +153,14 @@ in
       alsa.support32Bit = true;
 
       pulse.enable = true;
+
+      lowLatency = {
+        # enable this module
+        enable = true;
+        # defaults (no need to be set unless modified)
+        quantum = 64;
+        rate = 48000;
+      };
     };
     # udev configurations
     services.udev.packages = with pkgs; [

nki-home/audio/default.nix

@@ -0,0 +1,5 @@
+{ config, pkgs, lib, ... }: {
+  environment.etc = {
+    "wireplumber/main.lua.d/51-sdac.lua".source = ./sdac.lua;
+  };
+}

nki-home/audio/sdac.lua

@@ -0,0 +1,16 @@
+rule = {
+  matches = {
+    {
+      { "node.name", "matches", "alsa_output.usb-Grace_Design_SDAC-00.*" },
+    },
+  },
+  apply_properties = {
+    ["audio.format"] = "S24_3LE",
+    ["audio.rate"] = 96000,
+    ["api.alsa.period-size"] = 2,
+    ["api.alsa.headroom"] = 0,
+    ["api.alsa.disable-batch"] = true
+  },
+}
+
+table.insert(alsa_monitor.rules, rule)

nki-home/hardware-configuration.nix

@@ -7,6 +7,7 @@
   imports =
     [
       (modulesPath + "/installer/scan/not-detected.nix")
+      ./audio
     ];
 
   boot.initrd.availableKernelModules = [ "nvme" "xhci_pci" "ahci" "usbhid" "usb_storage" "sd_mod" ];