Electric guitar interface setup: Difference between revisions

Line 1:

= Electric guitar interface setup =

This guide covers setting up an electric guitar with NixOS to achieve professional, low-latency audio processing. It targets live playing with round-trip latency under 6 ms using the modern PipeWire/JACK stack.

This guide covers setting up an electric guitar with NixOS to achieve professional, low-latency audio processing. It targets live playing with round-trip latency (RTL) under 6 ms using the modern PipeWire/JACK stack.

'''⚠️ Safety Warning''': Always start with monitoring volume at minimum when testing new signal chains. A sudden, loud feedback loop can be generated during loopback testing. Increase volume gradually only after the plugin is open and stable.

== Introduction ==

Line 9:

Line 11:

# '''Analog-to-Digital conversion''' via an external audio interface.

# '''Real-time processing''' on NixOS using a low-latency kernel and specialized software.

'''Note''': Software-reported latency values are often inaccurate. Physical measurement via loopback test is mandatory for verification.

== Installation ==

Line 14:

Line 18:

=== System Configuration ===

Add the following to your `/etc/nixos/configuration.nix`. This configuration is optimized for high-performance CPUs like the ~~'''~~AMD Ryzen 7 9700X~~'''~~.

Add the following to your <code>/etc/nixos/configuration.nix</code>. This configuration is optimized for high-performance CPUs like the AMD Ryzen 7 9700X (Zen 5 architecture).

{ pkgs, ... }:

{ pkgs, config, ... }:

{

Line 24:

Line 28:

enable = true;

alsa.enable = true;

alsa.support32Bit = true;

alsa.support32Bit = true; # Required for yabridge/wine VST bridging

pulse.enable = true;

jack.enable = true;

wireplumber.enable = true;

# Global low-latency defaults

# Global low-latency defaults for native JACK clients

extraConfig.pipewire."92-low-latency" = {

"context.properties" = {

"default.clock.rate" = 48000;

"default.clock.rate" = 48000; # Fixed rate avoids resampling latency

"default.clock.quantum" = 128; # ~5ms latency

"default.clock.quantum" = 128; # ~5ms latency at 48kHz

"default.clock.min-quantum" = 64; # ~2.5ms latency

"default.clock.min-quantum" = 64; # ~2.5ms latency at 48kHz

"default.clock.max-quantum" = 512;

};

# Crucial: Match low-latency for PulseAudio clients (browsers, Steam/Rocksmith)

extraConfig.pipewire-pulse."92-low-latency" = {

"pulse.properties" = {

"pulse.min.req" = "64/48000"; # Start with 64, not 32, for stability

"pulse.default.req" = "64/48000";

"pulse.max.req" = "128/48000";

};

# 2. Real-time Scheduling ~~and Privileges~~

# 2. Real-time Scheduling

# RTKit handles real-time privileges via D-Bus/Polkit.

security.rtkit.enable = true;

users.users.yourname.extraGroups = [ "audio~~" "realtime~~" ];

# Critical: Allow unlimited memlock for real-time audio buffers

security.pam.loginLimits = [

{

domain = "@audio";

item = "memlock";

type = "-";

value = "unlimited";

}

{

domain = "@audio";

item = "rtprio";

type = "-";

value = "95";

}

];

users.users.yourname.extraGroups = [ "audio" ]; # Replace 'yourname' with your username

# 3. Kernel and Performance Tweaks

boot.kernelPackages = pkgs.linuxPackages_zen;

boot.kernelParams = [

"preempt=full"

"threadirqs"

"~~threadirqs~~"

"preempt=full" # Optional: add if experiencing Xruns

"~~usbcore.autosuspend~~=-1"

"amd_pstate=passive" # Zen 4/5: passive + performance governor = stable freq

"~~processor~~.~~max_cstate~~=1"

# For Intel or older AMD: remove amd_pstate or use "intel_pstate=active"

"usbcore.autosuspend=-1" # Prevent USB audio interface sleep

];

powerManagement.cpuFreqGovernor = "performance";

# GameMode can elevate priorities for real-time audio applications

programs.gamemode.enable = true;

# 4. NVIDIA Workaround (If applicable)

# For RTX 40/50 series: disable GSP firmware to prevent DPC latency spikes

# hardware.nvidia.powerManagement.enable = false;

# hardware.nvidia.modesetting.enable = true;

# boot.extraModprobeConfig = "options nvidia NVreg_EnableGpuFirmware=0";

# 5. Plugin Search Paths (Crucial for NixOS DAWs)

# Use sessionVariables for GUI apps launched from DE menu

environment.sessionVariables = let

makePluginPath = format = (pkgs.lib.makeSearchPath format [

"/run/current-system/sw/lib"

"${config.users.users.yourname.home}/.nix-profile/lib" # Adjust if using home-manager

]) + ":$HOME/.${format}";

in {

LV2_PATH = makePluginPath "lv2";

VST3_PATH = makePluginPath "vst3";

CLAP_PATH = makePluginPath "clap"; # Modern plugin format, supported by LSP/Chow

};

# 4. Essential Packages

# 6. Essential Packages

nixpkgs.config.allowUnfree = true;

nixpkgs.config.allowUnfree = true; # Required for REAPER, Tonelib, etc.

environment.systemPackages = with pkgs; [

qpwgraph

# --- Utilities & Routing ---

pavucontrol

qpwgraph # Visual patchbay for PipeWire

pavucontrol # Profile selection (Pro Audio mode)

pw-top # Real-time CPU usage per audio node

pw-cli # Modern alternative to pw-metadata

cpupower # CPU frequency scaling controls

alsa-scarlett-gui # Hardware mixer for Focusrite Scarlett (may require firmware)

# --- DAWs ---

ardour

reaper

carla

# --- Plugin Hosts ---

carla # Modular plugin host / pedalboard, supports Windows VST via yabridge

# --- Standalone Guitar Processors ---

guitarix

~~gxplugins~~-lv2

# tonelib-gfx # NOTE: Currently marked as broken in nixpkgs; install from vendor if needed

lsp-plugins

# --- Plugins (LV2/CLAP) ---

neural-amp-modeler-lv2 # NAM: loads .nam files from https://tonehunt.org

lsp-plugins # Includes latency meter, compressors, IR loader

calf

dragonfly-reverb

~~neural~~-amp-~~modeler~~-lv2

gxplugins-lv2

~~proteus~~

kapitonov-plugins-pack # Profile-based amp models (KPP)

~~kapitonov~~-~~plugins~~-~~pack~~

chow-centaur # Klon Centaur emulation

chow-phaser

# airwindows-lv2 # NOTE: Large package (~400 plugins); consider selective install

# --- Practice & Learning ---

tuxguitar

hydrogen

~~cpupower~~

# --- Windows VST Compatibility ---

yabridge

yabridgectl

wineWowPackages.stable # Use stable, not staging, for VST compatibility

];

}

</syntaxhighlight>

'''Note on <code>musnix</code>''': For advanced users, the [https://github.com/musnix/musnix musnix] flake automates many low-level audio optimizations (such as <code>PREEMPT_RT</code> kernel patching, <code>rtirq</code> tuning, and <code>das_watchdog</code>). If you experience persistent Xruns with the standard Zen kernel, replacing manual tweaks with <code>musnix.enable = true;</code> is highly recommended. '''Warning''': musnix may require replacing your kernel and can affect compatibility with Steam/Wine applications.

=== Applying Changes ===

Line 82:

Line 160:

sudo nixos-rebuild switch

# Apply PipeWire configuration changes (required after rebuild):

systemctl --user restart pipewire pipewire-pulse wireplumber

</syntaxhighlight>

== Hardware & Connection ==

~~=== Audio Interface ===~~

Standard PC line-ins are unsuitable for guitar. Use a dedicated interface with a '''Hi-Z (Instrument)''' input.

~~Standard PC line~~-~~ins are unsuitable~~ for ~~guitar~~. ~~Use a dedicated~~ interface ~~with a~~ '''~~Hi-Z (Instrument)~~''' ~~input~~.

=== Verified compatible devices (2026) ===

{| class="wikitable"

! Device !! Notes

|-

| '''Focusrite Scarlett Solo (4th Gen)''' || Plug-and-play. Use <code>alsa-scarlett-gui</code> for hardware monitoring. May require firmware update.

|-

| '''MOTU M2 / M4''' || Native ALSA kernel support for direct hardware mixer control via <code>alsamixer</code>. Exceptionally stable USB-C latency.

|-

| '''Universal Audio Volt 276''' || Reliable USB-C class-compliant interface.

|-

| '''Arturia MiniFuse 1''' || Stable performance under PipeWire.

|}

=== Hardware Rules ===

'''~~Verified compatible devices (2026):'~~''

# Connect the interface '''directly to the motherboard''' (rear panel USB 3.0/3.2). Avoid USB hubs — they add latency and can cause Xruns.

* '~~''Focusrite Scarlett Solo~~ (~~4th Gen~~)~~:''' Plug-~~and-~~play~~, ~~excellent Linux support~~.

# Use a high-quality, shielded USB cable. Audio dropouts are frequently caused by cheap cables acting as antennas for electrical interference.

* '''~~Arturia MiniFuse 1:~~''' ~~Stable performance under PipeWire~~.

# '''Disable Bluetooth''' during live playing: <code>rfkill block bluetooth</code>. BT audio stack can generate interrupt storms causing Xruns.

=== Verification ===

lsusb # Confirm hardware connection

aplay -l # ~~Confirm~~ ALSA sees the interface

arecord -l # Verify ALSA sees the capture input

aplay -l # Verify ALSA sees the playback output

# For detailed interface capabilities:

arecord --dump-hw-params -D hw:<card>,<device>

</syntaxhighlight>

Line 106:

Line 204:

To achieve minimal latency, you must bypass standard software mixing:

# Open <~~nowiki~~>pavucontrol</~~nowiki~~>.

# Go to '''Configuration'''.

# Open <code>pavucontrol</code>.

# Go to '''Configuration''' tab.

# Set your interface profile to '''Pro Audio'''.

'''Note''': If "Pro Audio" profile is missing, ensure <code>pipewire-alsa</code> is installed and restart PipeWire. This profile disables software mixing and enables hardware-exclusive mode, critical for achieving lowest latency.

=== Dynamic Buffer Control ===

You can change latency without rebuilding the system:

You can change latency without rebuilding the system. Note: these settings affect PipeWire clients only; ALSA-direct applications (like Ardour with ALSA backend) use their own buffer settings.

# ~~Force a specific buffer size~~ (~~quantum~~)

# Modern syntax (PipeWire 0.3.65+):

pw-~~metadata~~ -~~n settings~~ 0 clock.force-quantum 64

pw-cli set-param 0 clock.force-quantum 64/48000

# Verify current ~~status~~

# Verify current settings:

pw-~~metadata~~ -~~n settings 0~~

pw-cli dump settings | grep -E "quantum|rate"

# Alternative: use wpctl (WirePlumber CLI)

wpctl set-default-rate 48000

</syntaxhighlight>

== Software ~~Hosts~~ ==

Use <code>pw-top</code> in a separate terminal to monitor which applications are consuming the most DSP processing time. Look for the <code>ERR</code> column — values >0 indicate Xruns.

== Software Guide: Choosing Your Rig ==

This section explains the available software for guitar processing on NixOS, organized by purpose.

=== Digital Audio Workstations (DAWs) ===

{| class="wikitable"

! Software !! Purpose !! Notes

|-

| '''Ardour''' || Professional recording, mixing, editing || For absolute minimum RTL, use '''ALSA backend''' (bypasses PipeWire). Warning: ALSA locks device exclusively — no other app can produce sound.

|-

| '''REAPER''' || Commercial DAW, lightweight, scriptable || Uses PipeWire-JACK natively. Excellent Linux support. Unlimited trial.

|}

=== Amp Simulators & Neural Modelers ===

{| class="wikitable"

! ~~Type~~ !! ~~Examples~~ !! ~~Best Use Case~~

! Software !! Purpose !! Notes

|-

| '''~~Standalone~~''' || ~~Guitarix~~ || ~~Quick practice, simple pedalboard~~

| '''Neural Amp Modeler (NAM)''' (<code>neural-amp-modeler-lv2</code>) || Loads <code>.nam</code> files — AI captures of real tube amps || '''No built-in GUI in LV2 version'''. In Carla/Ardour: look for <code>atom:Path</code> parameter and point to your <code>.nam</code> file. Models: [https://tonehunt.org tonehunt.org]

|-

| '''~~Modular~~''' || ~~Carla~~ || ~~Flexible routing, loading Windows VSTs~~

| '''Kapitonov Plugins Pack (KPP)''' || Profile-based traditional amp modeling || Excellent for classic rock/metal. Lower CPU than neural nets.

|-

| '''~~DAW~~''' || ~~Ardour, Reaper~~ || ~~Professional recording, lowest latency via ALSA~~

| '''Guitarix''' || All-in-one virtual amp + pedals || Standalone or LV2. Good for quick practice.

|}

~~== Plugin Ecosystem~~ (~~March 2026 Status~~) ==

'''⚠️ Critical''': Neural amps (NAM, KPP) only model preamp/poweramp. '''You must load a Cabinet IR''' (via LSP IR Loader or similar) to get a usable guitar tone. Without IR, it sounds like a swarm of bees.

=== ~~Available in Nixpkgs~~ ===

=== Effects Plugins ===

* '''~~Neural Amp Modeler~~ (~~NAM~~):''' <~~nowiki~~>~~neural~~-~~amp~~-~~modeler-lv2~~</~~nowiki~~>~~. Current standard for high~~-fidelity ~~amp captures~~.

{| class="wikitable"

* '''~~LSP Plugins:~~''' ~~Includes <nowiki>LSP Latency Meter</nowiki>~~.

! Plugin Pack !! Key Features

* '''~~Proteus:~~''' ~~Excellent for RNN-based captures~~.

|-

| '''LSP Plugins''' || Professional EQ, compression, gating. '''Includes LSP Latency Meter''' and '''LSP Impulse Response Loader''' (required for cabinet sims).

|-

| '''Dragonfly Reverb''' || High-quality algorithmic reverb (Hall, Room, Plate).

|-

| '''Chow Plugins''' (<code>chow-centaur</code>, <code>chow-phaser</code>) || High-fidelity emulations of classic pedals using RNN/WDF.

|-

| '''Calf Studio Gear''' || Vintage-style effects with "warm" analog character.

|-

| '''GxPlugins.lv2''' || Guitarix project pedals (distortion, overdrive, fuzz) as standalone LV2.

|}

=== ~~Unavailable / Alternatives~~ ===

=== Modular Hosts ===

{| class="wikitable"

! Software !! Purpose

|-

| '''Carla''' || Modular plugin host. Chain plugins visually: Input → Tuner → NAM → IR Loader → Reverb → Output. Hosts Windows VSTs via yabridge.

|-

| '''qpwgraph''' || Visual patchbay for PipeWire/JACK. Manually connect hardware inputs to software hosts (PipeWire does not auto-connect).

|}

* '''~~Ratatouille~~ / ~~AIDA-X~~:''' ~~Currently not in nixpkgs~~. Use '''~~NAM~~''' or '''~~Proteus~~'''.

=== Windows VST Compatibility ===

* '''~~MOD Desktop~~:''' ~~Use~~ '''~~Carla~~''' ~~for similar modular functionality~~.

{| class="wikitable"

! Tool !! Purpose

|-

| '''yabridge + yabridgectl''' || Bridge for running Windows VST2/VST3 plugins on Linux via Wine. Essential for commercial plugins (Neural DSP, STL Tones, Amplitube).

|}

# After installing Windows plugins via Wine:

yabridgectl sync # Required to register plugins with Linux hosts

</syntaxhighlight>

'''Note''': Ensure glibc versions match between Wine and system. Check with <code>ldd /path/to/plugin.dll</code>.

== Rocksmith 2014 Remastered (Optional) ==

Rocksmith 2014 runs on NixOS via Proton and PipeWire.

=== Connection Options ===

{| class="wikitable"

! Method !! Pros !! Cons

|-

| '''Real Tone Cable''' || Official, plug-and-play || Proprietary, limited to 48kHz

|-

| '''Your Audio Interface + RS_ASIO''' || Use professional interface, any sample rate || Requires modding game files

|}

=== Setup Steps ===

# '''Install dependencies''':

# In configuration.nix:

programs.steam.enable = true;

programs.gamemode.enable = true; # For launch option below

</syntaxhighlight>

# '''Steam Launch Options''' (force low latency + real-time priority):

<pre>

PIPEWIRE_LATENCY=128/48000 gamemoderun %command%

</pre>

Start with <code>128/48000</code> (~5ms). If stable, try <code>64/48000</code> (~2.5ms). Values <64 may cause crashes.

# '''Sample Rate''': Rocksmith strictly requires '''48000 Hz'''. Do not force 96000 Hz while playing.

# '''If using Real Tone Cable and experiencing issues''', try ALSA backend as fallback (warning: exclusive device access):

# Only use if Pulse backend fails. May silence other apps.

protontricks 221680 sound=alsa

</syntaxhighlight>

# '''For interface users (no Real Tone Cable)''': Install [https://github.com/mdias/rs_asio RS_ASIO] mod to enable direct interface support. This bypasses the 48kHz limitation and allows using your professional interface.

== Measuring Latency ==

Never trust software reports. Always perform a physical loopback test:

Never trust software reports. Always perform a physical loopback test.

# Connect a cable from your interface '''Output''' back into the '''Input'''.

# ~~Open '''~~LSP Latency Meter~~'''~~.

=== Procedure ===

# ~~Measure~~ the '''Round-trip Latency (RTL)'''.

'''⚠️ Warning''': Before starting, turn output volume on your audio interface '''all the way down'''. A sudden, loud feedback loop can be generated if the connection is unstable. Increase volume gradually only after the plugin is open.

# Connect a cable from your interface '''Output''' back into the '''Input''' (use a TS/TRS patch cable).

# Launch LSP Latency Meter:

# Option A: Via Carla (recommended for beginners)

carla # Add plugin "LSP Latency Meter Stereo", connect wires

# Option B: Via jalv (terminal)

jalv http://lsp-plug.in/plugins/lv2/latency_meter_stereo

</syntaxhighlight>

# Play a sharp transient (string scratch) and read the '''Round-trip Latency (RTL)''' value.

=== Target Values ===

{| class="wikitable"

! Latency !! Perception

|-

| < 5 ms || Professional / Imperceptible

| '''< 5 ms''' || Professional / Imperceptible

|-

| ~~5-10~~ ms || Acceptable for practice

| '''5–10 ms''' || Acceptable for practice

|-

| > 12 ms || ~~Noticable~~ "lag", difficult to play

| '''> 12 ms''' || Noticeable "lag", difficult to play in time

|}

'''Note''': If measured latency exceeds calculated buffer latency <code>(buffer / sample_rate) * 2 * 1000</code>, check: USB interface hardware buffers, PipeWire extra quantum settings, kernel interrupt latency.

== Troubleshooting ==

* '''Xruns (~~Audio Glitches~~):''' Ensure <~~nowiki~~>powerManagement.cpuFreqGovernor = "performance"</~~nowiki~~> is active.

{| class="wikitable"

* '''No ~~Sound:~~''' Check <~~nowiki~~>qpwgraph</~~nowiki~~>. PipeWire does not ~~always~~ auto-connect.

! Symptom !! Cause & Solution

* '''NVIDIA ~~Latency:~~''' ~~Add~~ <~~nowiki~~>nvidia.~~NVreg_EnablePowerManagement~~=0</~~nowiki~~> to <~~nowiki~~>~~boot~~.~~kernelParams~~</~~nowiki~~>.

|-

| '''Xruns (audio glitches)''' || • Ensure <code>powerManagement.cpuFreqGovernor = "performance"</code> is active (<code>cpupower frequency-info</code>). • Check <code>pw-top</code> for high-CPU nodes. • Close browsers/heavy apps during playing. • Disable Wi-Fi: <code>sudo modprobe -r iwlwifi</code>. • As last resort: add <code>processor.max_cstate=1</code> to <code>boot.kernelParams</code> (disables CPU sleep — high power draw).

|-

| '''No sound''' || • Check <code>qpwgraph</code> — PipeWire does not auto-connect hardware. • Verify Pro Audio profile in <code>pavucontrol</code>. • Run <code>sudo lsof /dev/snd/*</code> to find conflicting processes.

|-

| '''DAW cannot find plugins''' || • Ensure <code>environment.sessionVariables</code> block is applied. Log out/in after rebuild. • Verify paths: <code>echo $LV2_PATH</code>. • Check plugin installation: <code>ls ~/.lv2</code>, <code>ls /run/current-system/sw/lib/lv2</code>.

|-

| '''NVIDIA audio glitches''' || • Disable GPU power management: <code>hardware.nvidia.powerManagement.enable = false;</code> • For RTX 40/50 series: add <code>boot.extraModprobeConfig = "options nvidia NVreg_EnableGpuFirmware=0";</code> • Prefer X11 over Wayland for lowest latency.

|-

| '''Bluetooth causing Xruns''' || • Disable Bluetooth stack: <code>rfkill block bluetooth</code> during live sessions.

|-

| '''PipeWire config not applying''' || • Restart user services after rebuild: <code>systemctl --user restart pipewire wireplumber</code>. • Check for WirePlumber overrides: <code>wpctl status</code>.

|}

== Quick Start Checklist ==

Before playing, verify:

# 1. CPU governor is performance

cpupower frequency-info | grep "current policy" # Should show "performance"

# 2. PipeWire buffer is set

pw-cli dump settings | grep quantum # Should show 64 or 128

# 3. No Xruns reported

pw-top | grep -E "ERR|XRUN" # Should show 0 or empty

# 4. Pro Audio profile active

pavucontrol # Configuration tab → your interface → Pro Audio

# 5. Plugin paths are set (for GUI apps)

echo $LV2_PATH # Should include /run/current-system/sw/lib/lv2

</syntaxhighlight>

== See Also ==

* [[PipeWire]]

* [https://github.com/musnix/musnix musnix] - Deep NixOS audio optimizations.

* [[PipeWire]] — Official NixOS PipeWire documentation

* [https://github.com/musnix/musnix musnix] — Deep NixOS audio optimizations module

* [https://linuxmusicians.com/ LinuxMusicians Forum] — Community support

* [https://tonehunt.org ToneHunt] — Free NAM model library

* [https://github.com/mdias/rs_asio RS_ASIO] — Rocksmith interface mod

[[Category:Guides]]

[[Category:Hardware]]

[[Category:Sound]]

@@ Line 1: / Line 1: @@
 = Electric guitar interface setup =
-This guide covers setting up an electric guitar with NixOS to achieve professional, low-latency audio processing. It targets live playing with round-trip latency under 6 ms using the modern PipeWire/JACK stack.
+This guide covers setting up an electric guitar with NixOS to achieve professional, low-latency audio processing. It targets live playing with round-trip latency (RTL) under 6 ms using the modern PipeWire/JACK stack.
+'''⚠️ Safety Warning''': Always start with monitoring volume at minimum when testing new signal chains. A sudden, loud feedback loop can be generated during loopback testing. Increase volume gradually only after the plugin is open and stable.
 == Introduction ==
@@ Line 9: / Line 11: @@
 # '''Analog-to-Digital conversion''' via an external audio interface.
 # '''Real-time processing''' on NixOS using a low-latency kernel and specialized software.
+'''Note''': Software-reported latency values are often inaccurate. Physical measurement via loopback test is mandatory for verification.
 == Installation ==
@@ Line 14: / Line 18: @@
 === System Configuration ===
-Add the following to your `/etc/nixos/configuration.nix`. This configuration is optimized for high-performance CPUs like the '''AMD Ryzen 7 9700X'''.
+Add the following to your <code>/etc/nixos/configuration.nix</code>. This configuration is optimized for high-performance CPUs like the AMD Ryzen 7 9700X (Zen 5 architecture).
 <syntaxhighlight lang="nix">
-{ pkgs, ... }:
+{ pkgs, config, ... }:
 {
@@ Line 24: / Line 28: @@
      enable = true;
      alsa.enable = true;
-     alsa.support32Bit = true;
+     alsa.support32Bit = true; # Required for yabridge/wine VST bridging
      pulse.enable = true;
      jack.enable = true;
      wireplumber.enable = true;
-     # Global low-latency defaults
+     # Global low-latency defaults for native JACK clients
      extraConfig.pipewire."92-low-latency" = {
        "context.properties" = {
-         "default.clock.rate" = 48000;
+         "default.clock.rate" = 48000;  # Fixed rate avoids resampling latency
-         "default.clock.quantum" = 128;      # ~5ms latency
+         "default.clock.quantum" = 128;      # ~5ms latency at 48kHz
-         "default.clock.min-quantum" = 64;   # ~2.5ms latency
+         "default.clock.min-quantum" = 64;   # ~2.5ms latency at 48kHz
          "default.clock.max-quantum" = 512;
+      };
+    };
+    # Crucial: Match low-latency for PulseAudio clients (browsers, Steam/Rocksmith)
+    extraConfig.pipewire-pulse."92-low-latency" = {
+      "pulse.properties" = {
+        "pulse.min.req" = "64/48000";    # Start with 64, not 32, for stability
+        "pulse.default.req" = "64/48000";
+        "pulse.max.req" = "128/48000";
        };
      };
    };
-   # 2. Real-time Scheduling and Privileges
+   # 2. Real-time Scheduling
+  # RTKit handles real-time privileges via D-Bus/Polkit.
    security.rtkit.enable = true;
-   users.users.yourname.extraGroups = [ "audio" "realtime" ];
+  # Critical: Allow unlimited memlock for real-time audio buffers
+  security.pam.loginLimits = [
+    {
+      domain = "@audio";
+      item = "memlock";
+      type = "-";
+      value = "unlimited";
+    }
+    {
+      domain = "@audio";
+      item = "rtprio";
+      type = "-";
+      value = "95";
+    }
+  ];
+   users.users.yourname.extraGroups = [ "audio" ]; # Replace 'yourname' with your username
    # 3. Kernel and Performance Tweaks
    boot.kernelPackages = pkgs.linuxPackages_zen;
    boot.kernelParams = [
-     "preempt=full"
+    "threadirqs"
-     "threadirqs"
+     "preempt=full"              # Optional: add if experiencing Xruns
-     "usbcore.autosuspend=-1"
+     "amd_pstate=passive"        # Zen 4/5: passive + performance governor = stable freq
-     "processor.max_cstate=1"
+     # For Intel or older AMD: remove amd_pstate or use "intel_pstate=active"
+     "usbcore.autosuspend=-1"    # Prevent USB audio interface sleep
    ];
    powerManagement.cpuFreqGovernor = "performance";
+  # GameMode can elevate priorities for real-time audio applications
+  programs.gamemode.enable = true;
+  # 4. NVIDIA Workaround (If applicable)
+  # For RTX 40/50 series: disable GSP firmware to prevent DPC latency spikes
+  # hardware.nvidia.powerManagement.enable = false;
+  # hardware.nvidia.modesetting.enable = true;
+  # boot.extraModprobeConfig = "options nvidia NVreg_EnableGpuFirmware=0";
+  # 5. Plugin Search Paths (Crucial for NixOS DAWs)
+  # Use sessionVariables for GUI apps launched from DE menu
+  environment.sessionVariables = let
+    makePluginPath = format = (pkgs.lib.makeSearchPath format [
+      "/run/current-system/sw/lib"
+      "${config.users.users.yourname.home}/.nix-profile/lib"  # Adjust if using home-manager
+    ]) + ":$HOME/.${format}";
+  in {
+    LV2_PATH = makePluginPath "lv2";
+    VST3_PATH = makePluginPath "vst3";
+    CLAP_PATH = makePluginPath "clap";  # Modern plugin format, supported by LSP/Chow
+  };
-   # 4. Essential Packages
+   # 6. Essential Packages
-   nixpkgs.config.allowUnfree = true;
+   nixpkgs.config.allowUnfree = true; # Required for REAPER, Tonelib, etc.
    environment.systemPackages = with pkgs; [
-     qpwgraph
+    # --- Utilities & Routing ---
-     pavucontrol
+     qpwgraph            # Visual patchbay for PipeWire
+     pavucontrol         # Profile selection (Pro Audio mode)
+    pw-top              # Real-time CPU usage per audio node
+    pw-cli              # Modern alternative to pw-metadata
+    cpupower            # CPU frequency scaling controls
+    alsa-scarlett-gui   # Hardware mixer for Focusrite Scarlett (may require firmware)
+    # --- DAWs ---
      ardour
      reaper
-     carla
+    # --- Plugin Hosts ---
+     carla               # Modular plugin host / pedalboard, supports Windows VST via yabridge
+    # --- Standalone Guitar Processors ---
      guitarix
-     gxplugins-lv2
+     # tonelib-gfx       # NOTE: Currently marked as broken in nixpkgs; install from vendor if needed
-     lsp-plugins
+    # --- Plugins (LV2/CLAP) ---
+    neural-amp-modeler-lv2  # NAM: loads .nam files from https://tonehunt.org
+     lsp-plugins             # Includes latency meter, compressors, IR loader
      calf
      dragonfly-reverb
-     neural-amp-modeler-lv2
+     gxplugins-lv2
-    proteus
+    kapitonov-plugins-pack  # Profile-based amp models (KPP)
-     kapitonov-plugins-pack
+    chow-centaur            # Klon Centaur emulation
+    chow-phaser
+    # airwindows-lv2        # NOTE: Large package (~400 plugins); consider selective install
+     # --- Practice & Learning ---
      tuxguitar
      hydrogen
-     cpupower
+     # --- Windows VST Compatibility ---
+    yabridge
+    yabridgectl
+    wineWowPackages.stable  # Use stable, not staging, for VST compatibility
    ];
 }
 </syntaxhighlight>
+'''Note on <code>musnix</code>''': For advanced users, the [https://github.com/musnix/musnix musnix] flake automates many low-level audio optimizations (such as <code>PREEMPT_RT</code> kernel patching, <code>rtirq</code> tuning, and <code>das_watchdog</code>). If you experience persistent Xruns with the standard Zen kernel, replacing manual tweaks with <code>musnix.enable = true;</code> is highly recommended. '''Warning''': musnix may require replacing your kernel and can affect compatibility with Steam/Wine applications.
 === Applying Changes ===
@@ Line 82: / Line 160: @@
 <syntaxhighlight lang="bash">
 sudo nixos-rebuild switch
+# Apply PipeWire configuration changes (required after rebuild):
+systemctl --user restart pipewire pipewire-pulse wireplumber
 </syntaxhighlight>
 == Hardware & Connection ==
-=== Audio Interface ===
+Standard PC line-ins are unsuitable for guitar. Use a dedicated interface with a '''Hi-Z (Instrument)''' input.
-Standard PC line-ins are unsuitable for guitar. Use a dedicated interface with a '''Hi-Z (Instrument)''' input.
+=== Verified compatible devices (2026) ===
+{| class="wikitable"
+! Device !! Notes
+|-
+| '''Focusrite Scarlett Solo (4th Gen)''' || Plug-and-play. Use <code>alsa-scarlett-gui</code> for hardware monitoring. May require firmware update.
+|-
+| '''MOTU M2 / M4''' || Native ALSA kernel support for direct hardware mixer control via <code>alsamixer</code>. Exceptionally stable USB-C latency.
+|-
+| '''Universal Audio Volt 276''' || Reliable USB-C class-compliant interface.
+|-
+| '''Arturia MiniFuse 1''' || Stable performance under PipeWire.
+|}
+=== Hardware Rules ===
-'''Verified compatible devices (2026):'''
+# Connect the interface '''directly to the motherboard''' (rear panel USB 3.0/3.2). Avoid USB hubs — they add latency and can cause Xruns.
-* '''Focusrite Scarlett Solo (4th Gen):''' Plug-and-play, excellent Linux support.
+# Use a high-quality, shielded USB cable. Audio dropouts are frequently caused by cheap cables acting as antennas for electrical interference.
-* '''Arturia MiniFuse 1:''' Stable performance under PipeWire.
+# '''Disable Bluetooth''' during live playing: <code>rfkill block bluetooth</code>. BT audio stack can generate interrupt storms causing Xruns.
 === Verification ===
 <syntaxhighlight lang="bash">
-lsusb      # Confirm hardware connection
+lsusb                    # Confirm hardware connection
-aplay -l   # Confirm ALSA sees the interface
+arecord -l               # Verify ALSA sees the capture input
+aplay -l                 # Verify ALSA sees the playback output
+# For detailed interface capabilities:
+arecord --dump-hw-params -D hw:<card>,<device>
 </syntaxhighlight>
@@ Line 106: / Line 204: @@
 To achieve minimal latency, you must bypass standard software mixing:
-# Open <nowiki>pavucontrol</nowiki>.
-# Go to '''Configuration'''.
+# Open <code>pavucontrol</code>.
+# Go to '''Configuration''' tab.
 # Set your interface profile to '''Pro Audio'''.
+'''Note''': If "Pro Audio" profile is missing, ensure <code>pipewire-alsa</code> is installed and restart PipeWire. This profile disables software mixing and enables hardware-exclusive mode, critical for achieving lowest latency.
 === Dynamic Buffer Control ===
-You can change latency without rebuilding the system:
+You can change latency without rebuilding the system. Note: these settings affect PipeWire clients only; ALSA-direct applications (like Ardour with ALSA backend) use their own buffer settings.
 <syntaxhighlight lang="bash">
-# Force a specific buffer size (quantum)
+# Modern syntax (PipeWire 0.3.65+):
-pw-metadata -n settings 0 clock.force-quantum 64
+pw-cli set-param 0 clock.force-quantum 64/48000
-# Verify current status
+# Verify current settings:
-pw-metadata -n settings 0
+pw-cli dump settings | grep -E "quantum|rate"
+# Alternative: use wpctl (WirePlumber CLI)
+wpctl set-default-rate 48000
 </syntaxhighlight>
-== Software Hosts ==
+Use <code>pw-top</code> in a separate terminal to monitor which applications are consuming the most DSP processing time. Look for the <code>ERR</code> column — values >0 indicate Xruns.
+== Software Guide: Choosing Your Rig ==
+This section explains the available software for guitar processing on NixOS, organized by purpose.
+=== Digital Audio Workstations (DAWs) ===
+{| class="wikitable"
+! Software !! Purpose !! Notes
+|-
+| '''Ardour''' || Professional recording, mixing, editing || For absolute minimum RTL, use '''ALSA backend''' (bypasses PipeWire). Warning: ALSA locks device exclusively — no other app can produce sound.
+|-
+| '''REAPER''' || Commercial DAW, lightweight, scriptable || Uses PipeWire-JACK natively. Excellent Linux support. Unlimited trial.
+|}
+=== Amp Simulators & Neural Modelers ===
 {| class="wikitable"
-! Type !! Examples !! Best Use Case
+! Software !! Purpose !! Notes
 |-
-| '''Standalone''' || Guitarix || Quick practice, simple pedalboard
+| '''Neural Amp Modeler (NAM)''' (<code>neural-amp-modeler-lv2</code>) || Loads <code>.nam</code> files — AI captures of real tube amps || '''No built-in GUI in LV2 version'''. In Carla/Ardour: look for <code>atom:Path</code> parameter and point to your <code>.nam</code> file. Models: [https://tonehunt.org tonehunt.org]
 |-
-| '''Modular''' || Carla || Flexible routing, loading Windows VSTs
+| '''Kapitonov Plugins Pack (KPP)''' || Profile-based traditional amp modeling || Excellent for classic rock/metal. Lower CPU than neural nets.
 |-
-| '''DAW''' || Ardour, Reaper || Professional recording, lowest latency via ALSA
+| '''Guitarix''' || All-in-one virtual amp + pedals || Standalone or LV2. Good for quick practice.
 |}
-== Plugin Ecosystem (March 2026 Status) ==
+'''⚠️ Critical''': Neural amps (NAM, KPP) only model preamp/poweramp. '''You must load a Cabinet IR''' (via LSP IR Loader or similar) to get a usable guitar tone. Without IR, it sounds like a swarm of bees.
-=== Available in Nixpkgs ===
+=== Effects Plugins ===
-* '''Neural Amp Modeler (NAM):''' <nowiki>neural-amp-modeler-lv2</nowiki>. Current standard for high-fidelity amp captures.
+{| class="wikitable"
-* '''LSP Plugins:''' Includes <nowiki>LSP Latency Meter</nowiki>.
+! Plugin Pack !! Key Features
-* '''Proteus:''' Excellent for RNN-based captures.
+|-
+| '''LSP Plugins''' || Professional EQ, compression, gating. '''Includes LSP Latency Meter''' and '''LSP Impulse Response Loader''' (required for cabinet sims).
+|-
+| '''Dragonfly Reverb''' || High-quality algorithmic reverb (Hall, Room, Plate).
+|-
+| '''Chow Plugins''' (<code>chow-centaur</code>, <code>chow-phaser</code>) || High-fidelity emulations of classic pedals using RNN/WDF.
+|-
+| '''Calf Studio Gear''' || Vintage-style effects with "warm" analog character.
+|-
+| '''GxPlugins.lv2''' || Guitarix project pedals (distortion, overdrive, fuzz) as standalone LV2.
+|}
-=== Unavailable / Alternatives ===
+=== Modular Hosts ===
+{| class="wikitable"
+! Software !! Purpose
+|-
+| '''Carla''' || Modular plugin host. Chain plugins visually: Input → Tuner → NAM → IR Loader → Reverb → Output. Hosts Windows VSTs via yabridge.
+|-
+| '''qpwgraph''' || Visual patchbay for PipeWire/JACK. Manually connect hardware inputs to software hosts (PipeWire does not auto-connect).
+|}
-* '''Ratatouille / AIDA-X:''' Currently not in nixpkgs. Use '''NAM''' or '''Proteus'''.
+=== Windows VST Compatibility ===
-* '''MOD Desktop:''' Use '''Carla''' for similar modular functionality.
+{| class="wikitable"
+! Tool !! Purpose
+|-
+| '''yabridge + yabridgectl''' || Bridge for running Windows VST2/VST3 plugins on Linux via Wine. Essential for commercial plugins (Neural DSP, STL Tones, Amplitube).
+|}
+<syntaxhighlight lang="bash">
+# After installing Windows plugins via Wine:
+yabridgectl sync  # Required to register plugins with Linux hosts
+</syntaxhighlight>
+'''Note''': Ensure glibc versions match between Wine and system. Check with <code>ldd /path/to/plugin.dll</code>.
+== Rocksmith 2014 Remastered (Optional) ==
+Rocksmith 2014 runs on NixOS via Proton and PipeWire.
+=== Connection Options ===
+{| class="wikitable"
+! Method !! Pros !! Cons
+|-
+| '''Real Tone Cable''' || Official, plug-and-play || Proprietary, limited to 48kHz
+|-
+| '''Your Audio Interface + RS_ASIO''' || Use professional interface, any sample rate || Requires modding game files
+|}
+=== Setup Steps ===
+# '''Install dependencies''':
+<syntaxhighlight lang="nix">
+# In configuration.nix:
+programs.steam.enable = true;
+programs.gamemode.enable = true;  # For launch option below
+</syntaxhighlight>
+# '''Steam Launch Options''' (force low latency + real-time priority):
+<pre>
+PIPEWIRE_LATENCY=128/48000 gamemoderun %command%
+</pre>
+Start with <code>128/48000</code> (~5ms). If stable, try <code>64/48000</code> (~2.5ms). Values <64 may cause crashes.
+# '''Sample Rate''': Rocksmith strictly requires '''48000 Hz'''. Do not force 96000 Hz while playing.
+# '''If using Real Tone Cable and experiencing issues''', try ALSA backend as fallback (warning: exclusive device access):
+<syntaxhighlight lang="bash">
+# Only use if Pulse backend fails. May silence other apps.
+protontricks 221680 sound=alsa
+</syntaxhighlight>
+# '''For interface users (no Real Tone Cable)''': Install [https://github.com/mdias/rs_asio RS_ASIO] mod to enable direct interface support. This bypasses the 48kHz limitation and allows using your professional interface.
 == Measuring Latency ==
-Never trust software reports. Always perform a physical loopback test:
+Never trust software reports. Always perform a physical loopback test.
-# Connect a cable from your interface '''Output''' back into the '''Input'''.
-# Open '''LSP Latency Meter'''.
+=== Procedure ===
-# Measure the '''Round-trip Latency (RTL)'''.
+'''⚠️ Warning''': Before starting, turn output volume on your audio interface '''all the way down'''. A sudden, loud feedback loop can be generated if the connection is unstable. Increase volume gradually only after the plugin is open.
+# Connect a cable from your interface '''Output''' back into the '''Input''' (use a TS/TRS patch cable).
+# Launch LSP Latency Meter:
+<syntaxhighlight lang="bash">
+# Option A: Via Carla (recommended for beginners)
+carla  # Add plugin "LSP Latency Meter Stereo", connect wires
+# Option B: Via jalv (terminal)
+jalv http://lsp-plug.in/plugins/lv2/latency_meter_stereo
+</syntaxhighlight>
+# Play a sharp transient (string scratch) and read the '''Round-trip Latency (RTL)''' value.
+=== Target Values ===
 {| class="wikitable"
 ! Latency !! Perception
 |-
-| < 5 ms || Professional / Imperceptible
+| '''< 5 ms''' || Professional / Imperceptible
 |-
-| 5-10 ms || Acceptable for practice
+| '''5–10 ms''' || Acceptable for practice
 |-
-| > 12 ms || Noticable "lag", difficult to play
+| '''> 12 ms''' || Noticeable "lag", difficult to play in time
 |}
+'''Note''': If measured latency exceeds calculated buffer latency <code>(buffer / sample_rate) * 2 * 1000</code>, check: USB interface hardware buffers, PipeWire extra quantum settings, kernel interrupt latency.
 == Troubleshooting ==
-* '''Xruns (Audio Glitches):''' Ensure <nowiki>powerManagement.cpuFreqGovernor = "performance"</nowiki> is active.
+{| class="wikitable"
-* '''No Sound:''' Check <nowiki>qpwgraph</nowiki>. PipeWire does not always auto-connect.
+! Symptom !! Cause & Solution
-* '''NVIDIA Latency:''' Add <nowiki>nvidia.NVreg_EnablePowerManagement=0</nowiki> to <nowiki>boot.kernelParams</nowiki>.
+|-
+| '''Xruns (audio glitches)''' || • Ensure <code>powerManagement.cpuFreqGovernor = "performance"</code> is active (<code>cpupower frequency-info</code>).<br>• Check <code>pw-top</code> for high-CPU nodes.<br>• Close browsers/heavy apps during playing.<br>• Disable Wi-Fi: <code>sudo modprobe -r iwlwifi</code>.<br>• As last resort: add <code>processor.max_cstate=1</code> to <code>boot.kernelParams</code> (disables CPU sleep — high power draw).
+|-
+| '''No sound''' || • Check <code>qpwgraph</code> — PipeWire does not auto-connect hardware.<br>• Verify Pro Audio profile in <code>pavucontrol</code>.<br>• Run <code>sudo lsof /dev/snd/*</code> to find conflicting processes.
+|-
+| '''DAW cannot find plugins''' || • Ensure <code>environment.sessionVariables</code> block is applied. Log out/in after rebuild.<br>• Verify paths: <code>echo $LV2_PATH</code>.<br>• Check plugin installation: <code>ls ~/.lv2</code>, <code>ls /run/current-system/sw/lib/lv2</code>.
+|-
+| '''NVIDIA audio glitches''' || • Disable GPU power management: <code>hardware.nvidia.powerManagement.enable = false;</code><br>• For RTX 40/50 series: add <code>boot.extraModprobeConfig = "options nvidia NVreg_EnableGpuFirmware=0";</code><br>• Prefer X11 over Wayland for lowest latency.
+|-
+| '''Bluetooth causing Xruns''' || • Disable Bluetooth stack: <code>rfkill block bluetooth</code> during live sessions.
+|-
+| '''PipeWire config not applying''' || • Restart user services after rebuild: <code>systemctl --user restart pipewire wireplumber</code>.<br>• Check for WirePlumber overrides: <code>wpctl status</code>.
+|}
+== Quick Start Checklist ==
+Before playing, verify:
+<syntaxhighlight lang="bash">
+# 1. CPU governor is performance
+cpupower frequency-info | grep "current policy"  # Should show "performance"
+# 2. PipeWire buffer is set
+pw-cli dump settings | grep quantum  # Should show 64 or 128
+# 3. No Xruns reported
+pw-top | grep -E "ERR|XRUN"  # Should show 0 or empty
+# 4. Pro Audio profile active
+pavucontrol  # Configuration tab → your interface → Pro Audio
+# 5. Plugin paths are set (for GUI apps)
+echo $LV2_PATH  # Should include /run/current-system/sw/lib/lv2
+</syntaxhighlight>
 == See Also ==
-* [[PipeWire]]
-* [https://github.com/musnix/musnix musnix] - Deep NixOS audio optimizations.
+* [[PipeWire]] — Official NixOS PipeWire documentation
+* [https://github.com/musnix/musnix musnix] — Deep NixOS audio optimizations module
+* [https://linuxmusicians.com/ LinuxMusicians Forum] — Community support
+* [https://tonehunt.org ToneHunt] — Free NAM model library
+* [https://github.com/mdias/rs_asio RS_ASIO] — Rocksmith interface mod
 [[Category:Guides]]
 [[Category:Hardware]]
 [[Category:Sound]]