diff --git a/src-tauri/src/audio/mod.rs b/src-tauri/src/audio/mod.rs
index 738e665..be5ac28 100644
--- a/src-tauri/src/audio/mod.rs
+++ b/src-tauri/src/audio/mod.rs
@@ -287,9 +287,6 @@ impl MicActivity {
     }
 
     /// The loopback writer publishes its rate so frame positions map to windows.
-    // ponytail: wired into capture_loop + stop in the next Phase 3 slice; the
-    // struct + span logic land first, tested, so the wiring is mechanical.
-    #[allow(dead_code)]
     fn set_rate(&self, rate: u32) {
         self.rate.store(rate, Ordering::Relaxed);
     }
@@ -297,7 +294,6 @@ impl MicActivity {
     /// Flag the `audio.wav` frames `[start_frame, start_frame + mic.len())` as
     /// active when the pulled mic chunk is speech-level. Silence is left `false`
     /// (the default), so gaps between utterances don't become "You".
-    #[allow(dead_code)]
     fn mark(&self, start_frame: u64, mic: &[f32]) {
         let rate = self.rate.load(Ordering::Relaxed) as u64;
         if rate == 0 || mic.is_empty() {
@@ -379,6 +375,7 @@ impl WasapiCapture {
         event_sink: EventSink,
         bridge: Option<Arc<MicBridge>>,
         voice_sample: Option<Arc<VoiceSample>>,
+        mic_activity: Option<Arc<MicActivity>>,
         emit_level: bool,
     ) -> Result<CaptureHandle, AudioError> {
         let running = Arc::new(AtomicBool::new(true));
@@ -401,6 +398,7 @@ impl WasapiCapture {
                     &paused_th,
                     bridge.as_ref(),
                     voice_sample.as_ref(),
+                    mic_activity.as_ref(),
                     emit_level,
                 )
             })
@@ -423,6 +421,7 @@ impl WasapiCapture {
         frame_sink: FrameSink,
         event_sink: EventSink,
         bridge: Arc<MicBridge>,
+        mic_activity: Option<Arc<MicActivity>>,
     ) -> Result<CaptureHandle, AudioError> {
         self.start_capture(
             "wa-audio-capture",
@@ -433,6 +432,7 @@ impl WasapiCapture {
             event_sink,
             Some(bridge),
             None,
+            mic_activity,
             true,
         )
     }
@@ -458,6 +458,7 @@ impl WasapiCapture {
             event_sink,
             Some(bridge),
             voice_sample,
+            None,
             true,
         )
     }
@@ -481,6 +482,7 @@ impl AudioCapture for WasapiCapture {
             event_sink,
             None,
             None,
+            None,
             true,
         )
     }
@@ -500,6 +502,7 @@ impl AudioCapture for WasapiCapture {
             event_sink,
             None,
             None,
+            None,
             true,
         )
     }
@@ -671,6 +674,7 @@ fn capture_loop(
     paused: &AtomicBool,
     bridge: Option<&Arc<MicBridge>>,
     voice_sample: Option<&Arc<VoiceSample>>,
+    mic_activity: Option<&Arc<MicActivity>>,
     emit_level: bool,
 ) -> Result<CaptureSummary, AudioError> {
     wasapi::initialize_mta()
@@ -682,12 +686,16 @@ fn capture_loop(
     // UI can overlay them — but only the loopback stream writes a WAV.
     let mut session = open_capture_session(&direction, device_id)?;
     // Loopback publishes its rate so the mic knows what to resample to before
-    // pushing into the shared bridge (mic-into-recording, FR-CAP-7).
+    // pushing into the shared bridge (mic-into-recording, FR-CAP-7), and so the
+    // Phase 3 mic-activity timeline maps frame positions to windows.
     if is_loopback {
         if let Some(b) = bridge {
             b.rate
                 .store(session.format.get_samplespersec(), Ordering::Relaxed);
         }
+        if let Some(ma) = mic_activity {
+            ma.set_rate(session.format.get_samplespersec());
+        }
     }
     let spec = wav_spec_for(&session.format)?;
     let mut writer = match wav_path {
@@ -746,6 +754,9 @@ fn capture_loop(
                     b.rate
                         .store(new_session.format.get_samplespersec(), Ordering::Relaxed);
                 }
+                if let Some(ma) = mic_activity {
+                    ma.set_rate(new_session.format.get_samplespersec());
+                }
             }
             session = new_session;
             let _ = event_sink.try_send(CaptureEvent::DeviceChanged {
@@ -770,7 +781,11 @@ fn capture_loop(
                             * (session.format.get_bitspersample() as usize / 8);
                         let silence = vec![0u8; gap_frames * bpf];
                         let mic = b.pull(gap_frames);
+                        let before = frames_written;
                         frames_written += write_wav_bytes(w, &silence, &session.format, &mic)?;
+                        if let Some(ma) = mic_activity {
+                            ma.mark(before, &mic);
+                        }
                         last_write = Instant::now();
                     }
                 }
@@ -793,7 +808,11 @@ fn capture_loop(
                 Some(b) if is_loopback => b.pull(frame_count(&bytes, &session.format)),
                 _ => Vec::new(),
             };
+            let before = frames_written;
             frames_written += write_wav_bytes(w, &bytes, &session.format, &mic)?;
+            if let Some(ma) = mic_activity {
+                ma.mark(before, &mic);
+            }
         }
         let mono = decode_mono_f32(&bytes, &session.format)?;
 
@@ -1603,6 +1622,7 @@ mod tests {
             loop_tx,
             ev_tx,
             bridge.clone(),
+            None,
         ) {
             Ok(h) => h,
             Err(e) => {