diff --git a/lifelog-recorder/app/src/main/kotlin/com/lemon/lifelog/asr/SpeakerClusterer.kt b/lifelog-recorder/app/src/main/kotlin/com/lemon/lifelog/asr/SpeakerClusterer.kt
index 26066a1..927a1fb 100644
--- a/lifelog-recorder/app/src/main/kotlin/com/lemon/lifelog/asr/SpeakerClusterer.kt
+++ b/lifelog-recorder/app/src/main/kotlin/com/lemon/lifelog/asr/SpeakerClusterer.kt
@@ -159,13 +159,21 @@ class SpeakerClusterer(
                 }
 
                 val assignment = if (best != null && bestSim >= matchThreshold) {
-                    val n = minOf(best.count, maxSamplesPerCentroid)
-                    val merged = FloatArray(emb.size) { i -> (best.centroid[i] * n + emb[i]) / (n + 1) }
-                    l2normalize(merged)
-                    best.centroid = merged
-                    best.count += 1
-                    repo.speakers.updateEmbedding(best.id, merged.toLeBytes(), best.count)
-                    best.id to bestSim
+                    if (autoIndexOf(best.name) == null) {
+                        // 人工命名 anchor：只归属、**冻结质心不漂移**。否则 anchor 吸入相邻
+                        // 说话人的段后质心会朝其漂移、再吸走更多 → 雪球式吞并（实测秦子琛
+                        // 把宜博从 ~125 段啃到只剩 56）。冻结后 anchor 始终是用户标定的方向。
+                        best.id to bestSim
+                    } else {
+                        // 自动簇：滑动均值精修质心（自适应、不被早期样本钉死）。
+                        val n = minOf(best.count, maxSamplesPerCentroid)
+                        val merged = FloatArray(emb.size) { i -> (best.centroid[i] * n + emb[i]) / (n + 1) }
+                        l2normalize(merged)
+                        best.centroid = merged
+                        best.count += 1
+                        repo.speakers.updateEmbedding(best.id, merged.toLeBytes(), best.count)
+                        best.id to bestSim
+                    }
                 } else if (seg.durationMs >= minNewClusterMs) {
                     val norm = emb.copyOf().also { l2normalize(it) }
                     seq += 1