nixos-config/nixos/system/desktop/audio.nix

{ config, lib, pkgs, ... }:
let

  library = import ../../library { inherit pkgs lib; };

  mixxxBin = pkgs.writeShellScriptBin "mixxx"
    "${pkgs.mixxx}/bin/mixxx --settingsPath ${config.users.users.mainUser.home}/music-library/mixxx";
  mixxxDesktop = library.desktopFile mixxxBin { longName = "Mixxx"; };

  mixxxFreeBin = pkgs.writeShellScriptBin "mixxx-free"
    "${pkgs.mixxx}/bin/mixxx --settingsPath ${config.users.users.mainUser.home}/music-library-free/mixxx";
  mixxxFreeDesktop = library.desktopFile mixxxFreeBin { longName = "Mixxx"; };

in {

  system.custom.audio = {
    enable = true;
    sinks = [{
      name = "movieLimiterSink";
      queue = [
        {
          # compress all sounds
          plugin = "dyson_compress_1403";
          label = "dysonCompress";
          control = [
            "0" # peak limit (dB)
            "1" # release time (secons)
            "0.2" # fast compression ration (unknown what that means)
            "0.8" # compression ratio
          ];
        }
        {
          # limit sound
          plugin = "fast_lookahead_limiter_1913";
          label = "fastLookaheadLimiter";
          control = [
            "20" # input gain (db)
            "-10" # limit (db)
            "1.1" # release time (s)
          ];
        }
        {
          # avoid deep sounds
          plugin = "dj_eq_1901";
          label = "dj_eq";
          control = [
            "-9" # low  gain (db) (100Hz)
            "0" # mid  gain (db) (1000Hz)
            "0" # high gain (db) (10000Hz)
          ];
        }
      ];
    }];
  };

  programs.custom = {
    easytag.enable = true;
    espeak.enable = true;
  };

  environment.systemPackages = with pkgs; [
    audacious
    sox
    id3v2

    mixxxBin
    mixxxDesktop
    mixxxFreeBin
    mixxxFreeDesktop
  ];

}