diff --git a/client/public/version.js b/client/public/version.js
index 002f19c..4b92972 100644
--- a/client/public/version.js
+++ b/client/public/version.js
@@ -1,5 +1,5 @@
 // Maintainer-controlled web client version.
 // Format: YYYY.MM.DD Rn (example: 2026.02.20 R2)
-window.CHGRID_WEB_VERSION = "2026.02.25 R277";
+window.CHGRID_WEB_VERSION = "2026.02.25 R278";
 // Optional display timezone for timestamps. Falls back to America/Detroit if unset/invalid.
 window.CHGRID_TIME_ZONE = "America/Detroit";
diff --git a/client/src/audio/audioEngine.ts b/client/src/audio/audioEngine.ts
index b08fe0a..85abc45 100644
--- a/client/src/audio/audioEngine.ts
+++ b/client/src/audio/audioEngine.ts
@@ -7,7 +7,7 @@ import {
   type EffectId,
   type EffectRuntime,
 } from './effects';
-import { resolveSpatialMix } from './spatial';
+import { applySpatialMixToNodes, resolveSpatialMix, SPATIAL_RAMP_SECONDS, SPATIAL_TIME_CONSTANT_SECONDS } from './spatial';
 
 export type SpatialPeerRuntime = {
   nickname: string;
@@ -29,8 +29,6 @@ type SoundSpec = {
 };
 
 type OutputMode = 'stereo' | 'mono';
-const SPATIAL_RAMP_SECONDS = 0.2;
-const SPATIAL_TIME_CONSTANT_SECONDS = SPATIAL_RAMP_SECONDS / 3;
 const ONE_SHOT_ATTACK_SECONDS = 0.02;
 type ActiveSpatialSampleRuntime = {
   sourceX: number;
@@ -310,14 +308,16 @@ export class AudioEngine {
         nearFieldDistance: 1.5,
         nearFieldGain: 1,
       });
-      const gainValue = mix?.gain ?? 0;
       const listenGain = Number.isFinite(peer.listenGain) ? Math.max(0, peer.listenGain as number) : 1;
-      const panValue = mix?.pan ?? 0;
-      peer.gain.gain.setTargetAtTime(gainValue * listenGain, this.audioCtx.currentTime, SPATIAL_TIME_CONSTANT_SECONDS);
-      if (peer.panner) {
-        const resolvedPan = this.outputMode === 'mono' ? 0 : Math.max(-1, Math.min(1, panValue));
-        peer.panner.pan.setValueAtTime(resolvedPan, this.audioCtx.currentTime);
-      }
+      const scaledMix = mix ? { ...mix, gain: mix.gain * listenGain } : null;
+      applySpatialMixToNodes({
+        audioCtx: this.audioCtx,
+        gainNode: peer.gain,
+        pannerNode: peer.panner ?? null,
+        mix: scaledMix,
+        outputMode: this.outputMode,
+        transition: 'target',
+      });
     }
   }
 
@@ -627,19 +627,24 @@ export class AudioEngine {
       range: sample.range,
       baseGain: sample.baseGain,
     });
-    const gainValue = mix?.gain ?? 0;
     if (initial) {
+      const gainValue = mix?.gain ?? 0;
       sample.gainNode.gain.setTargetAtTime(gainValue, this.audioCtx.currentTime, ONE_SHOT_ATTACK_SECONDS);
-    } else {
-      sample.gainNode.gain.cancelScheduledValues(this.audioCtx.currentTime);
-      sample.gainNode.gain.linearRampToValueAtTime(gainValue, this.audioCtx.currentTime + SPATIAL_RAMP_SECONDS);
-    }
-    if (sample.pannerNode) {
-      const panValue = mix?.pan ?? 0;
-      const resolvedPan = this.outputMode === 'mono' ? 0 : Math.max(-1, Math.min(1, panValue));
-      sample.pannerNode.pan.cancelScheduledValues(this.audioCtx.currentTime);
-      sample.pannerNode.pan.linearRampToValueAtTime(resolvedPan, this.audioCtx.currentTime + SPATIAL_RAMP_SECONDS);
+      if (sample.pannerNode) {
+        const panValue = mix?.pan ?? 0;
+        const resolvedPan = this.outputMode === 'mono' ? 0 : Math.max(-1, Math.min(1, panValue));
+        sample.pannerNode.pan.setValueAtTime(resolvedPan, this.audioCtx.currentTime);
+      }
+      return;
     }
+    applySpatialMixToNodes({
+      audioCtx: this.audioCtx,
+      gainNode: sample.gainNode,
+      pannerNode: sample.pannerNode,
+      mix,
+      outputMode: this.outputMode,
+      transition: 'linear',
+    });
   }
 
   private async getSampleBuffer(url: string): Promise<AudioBuffer> {
diff --git a/client/src/audio/itemEmitRuntime.ts b/client/src/audio/itemEmitRuntime.ts
index 3a6ccb1..0672d3e 100644
--- a/client/src/audio/itemEmitRuntime.ts
+++ b/client/src/audio/itemEmitRuntime.ts
@@ -3,7 +3,7 @@ import { getItemTypeGlobalProperties } from '../items/itemRegistry';
 import { AudioEngine } from './audioEngine';
 import { connectEffectChain, disconnectEffectRuntime, type EffectId, type EffectRuntime } from './effects';
 import { normalizeRadioEffect, normalizeRadioEffectValue } from './radioStationRuntime';
-import { resolveSpatialMix } from './spatial';
+import { applySpatialMixToNodes, resolveSpatialMix } from './spatial';
 import { volumePercentToGain } from './volume';
 
 type EmitOutput = {
@@ -27,8 +27,6 @@ type EmitSpatialConfig = {
 const ITEM_EMIT_BASE_GAIN = 1;
 const SUBSCRIBE_PRELOAD_SQUARES = 5;
 const UNSUBSCRIBE_HYSTERESIS_SQUARES = 8;
-const SPATIAL_RAMP_SECONDS = 0.2;
-const SPATIAL_TIME_CONSTANT_SECONDS = SPATIAL_RAMP_SECONDS / 3;
 const STREAM_PLAY_RETRY_MS = 5000;
 const STREAM_PLAY_MAX_RETRIES = 6;
 const STREAM_PLAY_RESET_COOLDOWN_MS = 60000;
@@ -231,15 +229,17 @@ export class ItemEmitRuntime {
           rearGain: 0.4,
         },
       });
-      const gainValue = mix?.gain ?? 0;
-      const panValue = mix?.pan ?? 0;
       const emitVolume = volumePercentToGain(item.params.emitVolume, 100);
-      output.gain.gain.setTargetAtTime(gainValue * emitVolume, audioCtx.currentTime, SPATIAL_TIME_CONSTANT_SECONDS);
+      const scaledMix = mix ? { ...mix, gain: mix.gain * emitVolume } : null;
+      applySpatialMixToNodes({
+        audioCtx,
+        gainNode: output.gain,
+        pannerNode: output.panner,
+        mix: scaledMix,
+        outputMode: this.audio.getOutputMode(),
+        transition: 'linear',
+      });
       this.tryStartEmitPlayback(itemId, output.element);
-      if (output.panner) {
-        const resolvedPan = this.audio.getOutputMode() === 'mono' ? 0 : Math.max(-1, Math.min(1, panValue));
-        output.panner.pan.setTargetAtTime(resolvedPan, audioCtx.currentTime, SPATIAL_TIME_CONSTANT_SECONDS);
-      }
     }
   }
 
diff --git a/client/src/audio/radioStationRuntime.ts b/client/src/audio/radioStationRuntime.ts
index 392ea99..53257dc 100644
--- a/client/src/audio/radioStationRuntime.ts
+++ b/client/src/audio/radioStationRuntime.ts
@@ -1,7 +1,7 @@
 import { HEARING_RADIUS, type WorldItem } from '../state/gameState';
 import { EFFECT_IDS, clampEffectLevel, connectEffectChain, disconnectEffectRuntime, type EffectId, type EffectRuntime } from './effects';
 import { AudioEngine } from './audioEngine';
-import { resolveSpatialMix } from './spatial';
+import { applySpatialMixToNodes, resolveSpatialMix } from './spatial';
 import { volumePercentToGain } from './volume';
 
 export const RADIO_CHANNEL_OPTIONS = ['stereo', 'mono', 'left', 'right'] as const;
@@ -165,8 +165,6 @@ type RadioSpatialConfig = {
 
 const SUBSCRIBE_PRELOAD_SQUARES = 5;
 const UNSUBSCRIBE_HYSTERESIS_SQUARES = 8;
-const SPATIAL_RAMP_SECONDS = 0.2;
-const SPATIAL_TIME_CONSTANT_SECONDS = SPATIAL_RAMP_SECONDS / 3;
 const STREAM_PLAY_RETRY_MS = 5000;
 const STREAM_PLAY_MAX_RETRIES = 6;
 const STREAM_PLAY_RESET_COOLDOWN_MS = 60000;
@@ -305,13 +303,14 @@ export class RadioStationRuntime {
           rearGain: 0.4,
         },
       });
-      const gainValue = mix?.gain ?? 0;
-      const panValue = mix?.pan ?? 0;
-      output.gain.gain.setTargetAtTime(gainValue, audioCtx.currentTime, SPATIAL_TIME_CONSTANT_SECONDS);
-      if (output.panner) {
-        const resolvedPan = this.audio.getOutputMode() === 'mono' ? 0 : Math.max(-1, Math.min(1, panValue));
-        output.panner.pan.setTargetAtTime(resolvedPan, audioCtx.currentTime, SPATIAL_TIME_CONSTANT_SECONDS);
-      }
+      applySpatialMixToNodes({
+        audioCtx,
+        gainNode: output.gain,
+        pannerNode: output.panner,
+        mix,
+        outputMode: this.audio.getOutputMode(),
+        transition: 'linear',
+      });
     }
   }
 
diff --git a/client/src/audio/spatial.ts b/client/src/audio/spatial.ts
index e81cd06..fe6bda2 100644
--- a/client/src/audio/spatial.ts
+++ b/client/src/audio/spatial.ts
@@ -20,6 +20,45 @@ export type SpatialMixResult = {
   pan: number;
 };
 
+export const SPATIAL_RAMP_SECONDS = 0.2;
+export const SPATIAL_TIME_CONSTANT_SECONDS = SPATIAL_RAMP_SECONDS / 3;
+
+type SpatialOutputMode = 'stereo' | 'mono';
+
+type ApplySpatialNodeOptions = {
+  audioCtx: AudioContext;
+  gainNode: GainNode;
+  pannerNode: StereoPannerNode | null;
+  mix: SpatialMixResult | null;
+  outputMode: SpatialOutputMode;
+  transition: 'linear' | 'target';
+};
+
+/**
+ * Applies one resolved spatial mix to gain/pan nodes with a shared transition profile.
+ */
+export function applySpatialMixToNodes(options: ApplySpatialNodeOptions): void {
+  const { audioCtx, gainNode, pannerNode, mix, outputMode, transition } = options;
+  const gainValue = mix?.gain ?? 0;
+  const panValue = mix?.pan ?? 0;
+  const resolvedPan = outputMode === 'mono' ? 0 : Math.max(-1, Math.min(1, panValue));
+
+  if (transition === 'linear') {
+    gainNode.gain.cancelScheduledValues(audioCtx.currentTime);
+    gainNode.gain.linearRampToValueAtTime(gainValue, audioCtx.currentTime + SPATIAL_RAMP_SECONDS);
+    if (pannerNode) {
+      pannerNode.pan.cancelScheduledValues(audioCtx.currentTime);
+      pannerNode.pan.linearRampToValueAtTime(resolvedPan, audioCtx.currentTime + SPATIAL_RAMP_SECONDS);
+    }
+    return;
+  }
+
+  gainNode.gain.setTargetAtTime(gainValue, audioCtx.currentTime, SPATIAL_TIME_CONSTANT_SECONDS);
+  if (pannerNode) {
+    pannerNode.pan.setTargetAtTime(resolvedPan, audioCtx.currentTime, SPATIAL_TIME_CONSTANT_SECONDS);
+  }
+}
+
 type DirectionalProfile = {
   attenuationFactor: number;
   offAxisRatio: number;