diff --git a/requirements-runtime.txt b/requirements-runtime.txt
index 3d7f2da..8e489df 100644
--- a/requirements-runtime.txt
+++ b/requirements-runtime.txt
@@ -5,7 +5,11 @@ torch>=2.0
 torchaudio>=2.0
 numpy>=1.24
 scipy>=1.10
-librosa>=0.10
+# <0.11: pyin's voiced decision changed in 0.11 (white noise scores ~0.43
+# voiced vs 0.0 on 0.10), which silently shifts the calibrated multi-speaker
+# voicing gates (multi_speaker_merge_voiced_min et al). Re-calibrate before
+# raising this bound.
+librosa>=0.10,<0.11
 soundfile>=0.12
 
 # Web
diff --git a/requirements.lock b/requirements.lock
index 4c8f1b2..91366c4 100644
--- a/requirements.lock
+++ b/requirements.lock
@@ -5,8 +5,8 @@
   "backend": {
     "requirements_runtime": {
       "path": "requirements-runtime.txt",
-      "sha256": "a2e2fc3c1448ddd6b1caf661daa56a6b37086c36aba586b4e3a2f29a0a916133",
-      "line_count": 31
+      "sha256": "c013d714111e1198048b2a47bbdf7a05b706ae5e5cb05f3686877ed957726f56",
+      "line_count": 32
     },
     "frontend_lock": {
       "path": "frontend/package-lock.json",
diff --git a/src/auto_voice/inference/singing_conversion_pipeline.py b/src/auto_voice/inference/singing_conversion_pipeline.py
index 495834e..9927539 100644
--- a/src/auto_voice/inference/singing_conversion_pipeline.py
+++ b/src/auto_voice/inference/singing_conversion_pipeline.py
@@ -44,6 +44,10 @@ def _voiced_fraction(audio: np.ndarray, sample_rate: int, max_s: float = 20.0) -
     (calibrated leads: 0.76-0.87); harmony stacks / textures it would butcher
     score low (calibrated: 0.14-0.51). Measured on up to ``max_s`` of active
     audio with pyin fmin=80 fmax=1000, matching the calibration convention.
+
+    Calibration is coupled to librosa 0.10 pyin semantics (0.11 changed the
+    voiced decision: white noise jumps from 0.0 to ~0.43) — hence the
+    ``librosa<0.11`` bound in requirements-runtime.txt.
     """
     import librosa
 
diff --git a/tests/test_fork_hq_lane.py b/tests/test_fork_hq_lane.py
index 256da95..e23a575 100644
--- a/tests/test_fork_hq_lane.py
+++ b/tests/test_fork_hq_lane.py
@@ -33,7 +33,8 @@ def infer(self, audio, spk, emb, sr):
 
     monkeypatch.setattr(p, "_get_separator", lambda: FakeSep())
     monkeypatch.setattr(p, "_get_model_manager", lambda: FakeMM())
-    monkeypatch.setattr(p, "_extract_pitch", lambda a, sr: np.zeros(8, np.float32))
+    monkeypatch.setattr(p, "_extract_pitch",
+                        lambda a, sr, method=None: np.zeros(8, np.float32))
 
     res = p._convert_song_fork_hq(str(song), "prof-1", 1.0, 0.9, True, "balanced", 0.0)