feat(clients): wire RNNoise mic noise reduction into Windows, macOS, and iOS

Expose the existing send-side vc_set_input_noise_reduction C ABI (MIC-only,
mono, LOCAL — denoises captured mic PCM before input gain and VAD/PTT gate)
as a persisted global toggle in each client's audio settings, applied live
and re-applied on Join Voice. Mirrors the existing mic-gain wiring pattern.

- Shared Swift (VoiceCatCore): add setInputNoiseReduction(_:) wrapper
- Windows: P/Invoke + SetInputNoiseReduction wrapper, MicNoiseReduction in
  VoiceSettings, new checkbox in AudioSettingsForm (layout shifted +28px),
  apply on Join Voice; also fix stale 'planned - currently passthrough'
  label on the receive-side per-user NR checkbox (RNNoise now backs it)
- macOS: inputNoiseReduction state + UserDefaults in MainWindowController,
  NR checkbox + nrChanged action in SettingsWindowController
- iOS: inputNoiseReduction in VoiceState + setter + restore in SessionState,
  NR Toggle in SettingsView Voice section

Aux/screen are out of scope by design (core's NR guards kind == MIC). Apple
builds require a rebuilt VoiceCatCore.xcframework with VOICECAT_HAS_NS.

clients/apple/Sources/VoiceCatCore/VoiceCatClient.swift

@@ -417,6 +417,15 @@ public final class VoiceCatClient {
         VoiceCatResult(vc_set_input_gain(handle, gain < 0 ? 0 : gain))
     }
 
+    /// Send-side microphone noise suppression (RNNoise). Denoises captured MIC PCM before the
+    /// input gain and VAD/PTT gate, so everyone hears the cleaned signal (one pass for all
+    /// listeners). MIC stream only, mono only; always LOCAL — no protocol traffic. Independent
+    /// of the per-listener receive-side NR in `setRemoteStream` (docs/voice.md §10).
+    @discardableResult
+    public func setInputNoiseReduction(_ enable: Bool) -> VoiceCatResult {
+        VoiceCatResult(vc_set_input_noise_reduction(handle, enable ? 1 : 0))
+    }
+
     // MARK: - AVAudioSession interruption hooks (iOS)
 
     /// Pause miniaudio device I/O. Call when AVAudioSession interruption begins.

clients/apple/iOS/VoiceCatiOS/SessionState.swift

@@ -27,6 +27,7 @@ struct VoiceState {
     var inputMode: VoiceCatInputMode = .voiceActivation
     var vadThreshold: Float = 0.025
     var inputGain: Float = 1.0
+    var inputNoiseReduction: Bool = false
     var level: Float = 0.0
     var currentDeviceId: String?
     var localStreamId: UInt32 = 0
@@ -353,12 +354,19 @@ final class SessionState {
         UserDefaults.standard.set(gain, forKey: DefaultsKey.inputGain)
     }
 
+    func setInputNoiseReduction(_ on: Bool) {
+        client.setInputNoiseReduction(on)
+        voiceState.inputNoiseReduction = on
+        UserDefaults.standard.set(on, forKey: DefaultsKey.inputNoiseReduction)
+    }
+
     // MARK: - Persisted input settings
 
     private enum DefaultsKey {
         static let inputMode    = "voice.inputMode"
         static let vadThreshold = "voice.vadThreshold"
         static let inputGain    = "voice.inputGain"
+        static let inputNoiseReduction = "voice.inputNoiseReduction"
     }
 
     /// Restore the saved input mode / VAD threshold / mic gain and push them into the core so a
@@ -375,9 +383,13 @@ final class SessionState {
         if d.object(forKey: DefaultsKey.inputGain) != nil {
             voiceState.inputGain = d.float(forKey: DefaultsKey.inputGain)
         }
+        if d.object(forKey: DefaultsKey.inputNoiseReduction) != nil {
+            voiceState.inputNoiseReduction = d.bool(forKey: DefaultsKey.inputNoiseReduction)
+        }
         client.setInputMode(voiceState.inputMode)
         client.setVadThreshold(voiceState.vadThreshold)
         client.setInputGain(voiceState.inputGain)
+        client.setInputNoiseReduction(voiceState.inputNoiseReduction)
     }
 
     private var pttEngaged = false

clients/apple/iOS/VoiceCatiOS/Views/SettingsView.swift

@@ -251,6 +251,13 @@ struct SettingsView: View {
                         .accessibilityLabel("Microphone volume")
                         .accessibilityValue("\(Int((session.voiceState.inputGain * 100).rounded())) percent")
                     }
+
+                    Toggle("Noise Reduction (RNNoise)", isOn: Binding(
+                        get: { session.voiceState.inputNoiseReduction },
+                        set: { session.setInputNoiseReduction($0) }
+                    ))
+                    .accessibilityLabel("Microphone noise reduction")
+                    .accessibilityHint("Denoises your microphone signal for everyone listening.")
                 }
 
                 // MARK: - Notifications

clients/apple/macOS/VoiceCatMac/Windows/MainWindowController.swift

@@ -61,6 +61,7 @@ final class MainWindowController: NSWindowController, NSWindowDelegate {
         static let inputMode    = "voice.inputMode"
         static let vadThreshold = "voice.vadThreshold"
         static let inputGain    = "voice.inputGain"
+        static let inputNoiseReduction = "voice.inputNoiseReduction"
         static let pttKeyCode   = "voice.pttKeyCode"
         static let auxEnabled   = "voice.auxEnabled"
         static let auxDeviceUID = "voice.auxDeviceUID"
@@ -76,6 +77,9 @@ final class MainWindowController: NSWindowController, NSWindowDelegate {
     internal var inputGain: Float = 1.0 {
         didSet { UserDefaults.standard.set(inputGain, forKey: AudioDefaults.inputGain) }
     }
+    internal var inputNoiseReduction: Bool = false {
+        didSet { UserDefaults.standard.set(inputNoiseReduction, forKey: AudioDefaults.inputNoiseReduction) }
+    }
     internal var selectedInputDeviceId: String?
 
     // Aux outgoing stream: a second hardware input device the client captures itself and feeds to
@@ -156,6 +160,9 @@ final class MainWindowController: NSWindowController, NSWindowDelegate {
         if d.object(forKey: AudioDefaults.inputGain) != nil {
             inputGain = d.float(forKey: AudioDefaults.inputGain)
         }
+        if d.object(forKey: AudioDefaults.inputNoiseReduction) != nil {
+            inputNoiseReduction = d.bool(forKey: AudioDefaults.inputNoiseReduction)
+        }
         if d.object(forKey: AudioDefaults.pttKeyCode) != nil {
             pttKeyCode = UInt16(d.integer(forKey: AudioDefaults.pttKeyCode))
         }
@@ -779,6 +786,7 @@ final class MainWindowController: NSWindowController, NSWindowDelegate {
                     client.setVadThreshold(vadThresholdValue)
                 }
                 client.setInputGain(inputGain)
+                client.setInputNoiseReduction(inputNoiseReduction)
                 setVoiceJoinedState(true)
                 addActivity("Joined voice — microphone active")
                 EventFeedback.shared.play(.voiceOn)

clients/apple/macOS/VoiceCatMac/Windows/SettingsWindowController.swift

@@ -58,6 +58,11 @@ final class SettingsWindowController: NSWindowController, NSWindowDelegate {
     }()
     private let inputGainValueLabel = NSTextField(labelWithString: "100%")
 
+    // Send-side mic noise reduction (RNNoise). MIC-only. Persisted via
+    // MainWindowController.inputNoiseReduction.
+    private let nrCheckbox = NSButton(checkboxWithTitle: "Noise reduction (RNNoise)",
+                                       target: nil, action: nil)
+
     // Aux input stream: a second outgoing stream from another hardware input device (e.g. line-in
     // / aux), captured client-side. Device + volume only — aux is always-on. Persisted via
     // MainWindowController.auxEnabled / auxDeviceUID / auxGain.
@@ -168,6 +173,11 @@ final class SettingsWindowController: NSWindowController, NSWindowDelegate {
         inputGainSlider.setAccessibilityHelp("Boost a quiet microphone. 100% is unity.")
         inputGainValueLabel.setAccessibilityLabel("Microphone volume value")
 
+        nrCheckbox.target = self
+        nrCheckbox.action = #selector(nrChanged)
+        nrCheckbox.setAccessibilityLabel("Microphone noise reduction")
+        nrCheckbox.setAccessibilityHelp("RNNoise denoising of your microphone. Cleans your signal for everyone.")
+
         let inputModeRow = NSStackView(views: [inputModeLabel, inputModeControl])
         inputModeRow.orientation = .horizontal
         inputModeRow.spacing = 8
@@ -249,7 +259,7 @@ final class SettingsWindowController: NSWindowController, NSWindowDelegate {
         volumeRow.orientation = .horizontal
         volumeRow.spacing = 8
 
-        let stack = NSStackView(views: [inputModeRow, vadRow, inputGainRow, pttRow, deviceRow,
+        let stack = NSStackView(views: [inputModeRow, vadRow, inputGainRow, nrCheckbox, pttRow, deviceRow,
                                         levelRow, auxHeader, auxCheckbox, auxDeviceRow, auxGainRow,
                                         notificationsHeader, soundsCheckbox, volumeRow,
                                         speechCheckbox, selfTalkCheckbox, pttSoundCheckbox])
@@ -319,6 +329,7 @@ final class SettingsWindowController: NSWindowController, NSWindowDelegate {
 
         inputGainSlider.doubleValue = Double(mc.inputGain * 100)
         updateInputGainLabel()
+        nrCheckbox.state = mc.inputNoiseReduction ? .on : .off
 
         auxCheckbox.state = mc.auxEnabled ? .on : .off
         auxGainSlider.doubleValue = Double(mc.auxGain * 100)
@@ -371,6 +382,14 @@ final class SettingsWindowController: NSWindowController, NSWindowDelegate {
         }
     }
 
+    @objc private func nrChanged() {
+        let on = nrCheckbox.state == .on
+        mainController?.inputNoiseReduction = on
+        if let mc = mainController, mc.micStreamId != 0 {
+            client.setInputNoiseReduction(on)
+        }
+    }
+
     private func updateInputGainLabel() {
         let pct = Int(inputGainSlider.doubleValue.rounded())
         inputGainValueLabel.stringValue = "\(pct)%"

clients/windows/VoiceCat.App/Forms/AudioSettingsForm.cs

@@ -27,6 +27,7 @@ public sealed class AudioSettingsForm : Form
     private readonly VcInputMode _origMode;
     private readonly int _origVadSlider;
     private readonly int _origMicGain;
+    private readonly bool _origMicNoiseReduction;
     private readonly Keys _origPttKey;
     private readonly bool _origAuxEnabled;
     private readonly string? _origAuxDeviceId;
@@ -42,6 +43,7 @@ public sealed class AudioSettingsForm : Form
     private readonly Label _lblSensitivity;
     private readonly TrackBar _trkVad;
     private readonly TrackBar _trkGain;
+    private readonly CheckBox _chkNoiseReduction;
     private readonly CheckBox _chkAux;
     private readonly Label _lblAuxDevice;
     private readonly ComboBox _cboAuxDevice;
@@ -67,6 +69,7 @@ public sealed class AudioSettingsForm : Form
         _origMode = (VcInputMode)settings.InputMode;
         _origVadSlider = settings.VadThresholdSlider;
         _origMicGain = settings.MicGain;
+        _origMicNoiseReduction = settings.MicNoiseReduction;
         _origPttKey = _pttKey;
         _origAuxEnabled = settings.AuxEnabled;
         _origAuxDeviceId = settings.AuxDeviceId;
@@ -78,7 +81,7 @@ public sealed class AudioSettingsForm : Form
         MinimizeBox = false;
         StartPosition = FormStartPosition.CenterParent;
         AutoScaleMode = AutoScaleMode.Font;
-        ClientSize = new Size(420, 555);
+        ClientSize = new Size(420, 583);
 
         // ── Device row ────────────────────────────────────────────────────────
         var lblDevice = new Label
@@ -199,6 +202,21 @@ public sealed class AudioSettingsForm : Form
             "Boost a quiet microphone. 100 is unity gain; range 0–300 percent.";
         _trkGain.Scroll += TrkGain_Scroll;
 
+        // ── Mic noise reduction ───────────────────────────────────────────────
+        // Send-side RNNoise denoise of the mic stream. MIC-only (the core's NR runs before
+        // the input gain and VAD/PTT gate; aux/screen are excluded). One pass for all listeners.
+        _chkNoiseReduction = new CheckBox
+        {
+            Text = "Noise &reduction (RNNoise)",
+            Location = new Point(12, 340),
+            AutoSize = true,
+            Checked = settings.MicNoiseReduction,
+            AccessibleName = "Microphone noise reduction",
+            AccessibleDescription =
+                "RNNoise denoising of your microphone. Cleans your signal for everyone listening.",
+        };
+        _chkNoiseReduction.CheckedChanged += ChkNoiseReduction_CheckedChanged;
+
         // ── Aux input stream ──────────────────────────────────────────────────
         // A second outgoing stream from another hardware input device (e.g. line-in / aux),
         // captured client-side and fed to the core. Device + volume only — aux is always-on
@@ -206,7 +224,7 @@ public sealed class AudioSettingsForm : Form
         _chkAux = new CheckBox
         {
             Text = "&Aux stream (second input device)",
-            Location = new Point(12, 348),
+            Location = new Point(12, 376),
             AutoSize = true,
             Checked = settings.AuxEnabled,
             AccessibleName = "Enable aux input stream",
@@ -218,12 +236,12 @@ public sealed class AudioSettingsForm : Form
         _lblAuxDevice = new Label
         {
             Text = "Aux d&evice:",
-            Location = new Point(12, 378),
+            Location = new Point(12, 406),
             AutoSize = true,
         };
         _cboAuxDevice = new ComboBox
         {
-            Location = new Point(12, 398),
+            Location = new Point(12, 426),
             Width = 300,
             DropDownStyle = ComboBoxStyle.DropDownList,
             DisplayMember = "Name",
@@ -236,7 +254,7 @@ public sealed class AudioSettingsForm : Form
         _btnAuxRefresh = new Button
         {
             Text = "Re&fresh",
-            Location = new Point(320, 396),
+            Location = new Point(320, 424),
             Size = new Size(80, 26),
         };
         _btnAuxRefresh.Click += (_, _) => LoadAuxDevices();
@@ -244,12 +262,12 @@ public sealed class AudioSettingsForm : Form
         _lblAuxGain = new Label
         {
             Text = "Aux vo&lume:",
-            Location = new Point(12, 434),
+            Location = new Point(12, 462),
             AutoSize = true,
         };
         _trkAuxGain = new TrackBar
         {
-            Location = new Point(12, 454),
+            Location = new Point(12, 482),
             Size = new Size(200, 45),
             Minimum = 0,
             Maximum = 300,
@@ -268,14 +286,14 @@ public sealed class AudioSettingsForm : Form
         {
             Text = "&OK",
             DialogResult = DialogResult.OK,
-            Location = new Point(228, 516),
+            Location = new Point(228, 544),
             Size = new Size(80, 27),
         };
         var btnCancel = new Button
         {
             Text = "&Cancel",
             DialogResult = DialogResult.Cancel,
-            Location = new Point(316, 516),
+            Location = new Point(316, 544),
             Size = new Size(80, 27),
         };
 
@@ -292,7 +310,7 @@ public sealed class AudioSettingsForm : Form
             lblDevice, _cboDevice, _btnRefresh,
             lblMode, _radioVad, _lblSensitivity, _trkVad,
             _radioPtt, _lblPttKey, _btnChangePtt, _radioAlwaysOn,
-            lblGain, _trkGain,
+            lblGain, _trkGain, _chkNoiseReduction,
             _chkAux, _lblAuxDevice, _cboAuxDevice, _btnAuxRefresh, _lblAuxGain, _trkAuxGain,
             btnOk, btnCancel,
         ]);
@@ -430,6 +448,13 @@ public sealed class AudioSettingsForm : Form
             _client.SetInputGain(_trkGain.Value / 100f);
     }
 
+    private void ChkNoiseReduction_CheckedChanged(object? sender, EventArgs e)
+    {
+        _settings.MicNoiseReduction = _chkNoiseReduction.Checked;
+        if (_micStreamId != 0)
+            _client.SetInputNoiseReduction(_chkNoiseReduction.Checked);
+    }
+
     private void BtnChangePtt_Click(object? sender, EventArgs e)
     {
         using var dlg = new PttKeyCaptureDialog(_pttKey);
@@ -450,6 +475,7 @@ public sealed class AudioSettingsForm : Form
         _settings.InputMode = (int)_origMode;
         _settings.VadThresholdSlider = _origVadSlider;
         _settings.MicGain = _origMicGain;
+        _settings.MicNoiseReduction = _origMicNoiseReduction;
         _settings.PttKey = (int)_origPttKey;
 
         if (_micStreamId != 0)
@@ -459,6 +485,7 @@ public sealed class AudioSettingsForm : Form
             if (_origMode == VcInputMode.VoiceActivation)
                 _client.SetVadThreshold(0.1f * (1f - (_origVadSlider - 1f) / 99f));
             _client.SetInputGain(_origMicGain / 100f);
+            _client.SetInputNoiseReduction(_origMicNoiseReduction);
         }
 
         // Aux: restore originals to settings and re-apply live (order: device + gain first so a

clients/windows/VoiceCat.App/Forms/MainForm.cs

@@ -650,6 +650,7 @@ public partial class MainForm : Form
                 if (mode == VcInputMode.VoiceActivation)
                     _client.SetVadThreshold(VadThresholdFromSettings());
                 _client.SetInputGain(_voiceSettings.MicGain / 100f);
+                _client.SetInputNoiseReduction(_voiceSettings.MicNoiseReduction);
                 SetVoiceJoinedState(true);
                 AddActivity("Joined voice — microphone active");
                 _feedback.PlaySound(SoundEvent.VoiceOn);

clients/windows/VoiceCat.App/Forms/PerUserTuningDialog.cs

@@ -150,7 +150,7 @@ public sealed class PerUserTuningDialog : Form
 
         var chkNr = new CheckBox
         {
-            Text = "&Noise reduction (planned — currently passthrough)",
+            Text = "&Noise reduction",
             AutoSize = true,
             Location = new Point(96, y + 48),
             Checked = nr0,

clients/windows/VoiceCat.App/Models/VoiceSettings.cs

@@ -21,6 +21,11 @@ public sealed class VoiceSettings
     /// <summary>Microphone input gain slider position, 0–300 percent (100 = unity).</summary>
     public int MicGain { get; set; } = 100;
 
+    /// <summary>Send-side mic noise reduction (RNNoise) toggle. MIC stream only, mono only;
+    /// denoises captured mic PCM before input gain and VAD/PTT gate so everyone hears the
+    /// cleaned signal. Independent of the per-listener receive-side NR.</summary>
+    public bool MicNoiseReduction { get; set; } = false;
+
     /// <summary>Push-to-talk key, stored as the integer value of System.Windows.Forms.Keys.</summary>
     public int PttKey { get; set; } = (int)Keys.F8;
 

clients/windows/VoiceCat.Interop/NativeMethods.cs

@@ -83,6 +83,9 @@ internal static partial class NativeMethods
     [LibraryImport(LibName)]
     internal static partial VcResult vc_set_input_gain(nint c, float gain);
 
+    [LibraryImport(LibName)]
+    internal static partial VcResult vc_set_input_noise_reduction(nint c, int enable);
+
     [LibraryImport(LibName)]
     internal static partial VcResult vc_set_remote_stream(nint c, uint userId, uint streamId,
         float gain, int muted, int noiseReduction);

clients/windows/VoiceCat.Interop/VoiceCatClient.cs

@@ -232,6 +232,13 @@ public sealed class VoiceCatClient : IDisposable
     public VcResult SetInputGain(float gain) =>
         NativeMethods.vc_set_input_gain(_handle.DangerousGetHandle(), gain < 0f ? 0f : gain);
 
+    /// <summary>Send-side microphone noise suppression (RNNoise). Denoises captured MIC PCM before
+    /// the input gain and VAD/PTT gate, so everyone hears the cleaned signal. MIC stream only,
+    /// mono only; always LOCAL — no protocol traffic. Independent of per-listener receive-side
+    /// NR in <see cref="SetRemoteStream"/>.</summary>
+    public VcResult SetInputNoiseReduction(bool enable) =>
+        NativeMethods.vc_set_input_noise_reduction(_handle.DangerousGetHandle(), enable ? 1 : 0);
+
     public VcResult SetRemoteStream(uint userId, uint streamId, float gain, bool muted, bool noiseReduction) =>
         NativeMethods.vc_set_remote_stream(_handle.DangerousGetHandle(), userId, streamId, gain,
             muted ? 1 : 0, noiseReduction ? 1 : 0);