diff --git a/frontend/src/lib/voice/useVoiceCapture.ts b/frontend/src/lib/voice/useVoiceCapture.ts
index 5008fbf..f17a74e 100644
--- a/frontend/src/lib/voice/useVoiceCapture.ts
+++ b/frontend/src/lib/voice/useVoiceCapture.ts
@@ -219,6 +219,14 @@ export function useVoiceCapture({
           // minutes of dictation because a timer expired would be the worst failure.
           if (maxMs != null && elapsed >= maxMs) stop();
         }, LEVEL_POLL_MS);
+      } catch {
+        // `new MediaRecorder(...)` and `recorder.start()` both throw on some browsers,
+        // and by then the stream is already live. Without this the promise rejects
+        // unhandled, the UI sits at 'idle' with nothing shown, and the browser's
+        // recording indicator stays lit until the workspace unmounts.
+        teardown();
+        setPhase('idle');
+        onError(clientError('VOICE_MIC_DENIED'));
       } finally {
         startingRef.current = false;
       }
@@ -262,12 +270,23 @@ function attachLevelMeter(
     source.connect(analyser);
 
     const data = new Uint8Array(analyser.frequencyBinCount);
-    const tick = () => {
+    // Sample every frame so a transient is not missed, but publish at LEVEL_POLL_MS.
+    // This hook lives in TreatmentWorkspace, so an unthrottled setLevel re-renders the
+    // details editor, the FDI chart and the lab panel on every animation frame — about
+    // 7,200 whole-tree renders across a two-minute recording.
+    let peakSinceEmit = 0;
+    let lastEmit = 0;
+    const tick = (now: number) => {
       if (contextRef.current !== context || context.state === 'closed') return;
       analyser.getByteTimeDomainData(data);
       let peak = 0;
       for (const sample of data) peak = Math.max(peak, Math.abs(sample - 128));
-      setLevel(Math.min(1, peak / 128));
+      peakSinceEmit = Math.max(peakSinceEmit, peak);
+      if (now - lastEmit >= LEVEL_POLL_MS) {
+        lastEmit = now;
+        setLevel(Math.min(1, peakSinceEmit / 128));
+        peakSinceEmit = 0;
+      }
       requestAnimationFrame(tick);
     };
     requestAnimationFrame(tick);