diff --git a/party-stage/src/scene/fps-counter.js b/party-stage/src/scene/fps-counter.js
index e2ec284..bcc5d36 100644
--- a/party-stage/src/scene/fps-counter.js
+++ b/party-stage/src/scene/fps-counter.js
@@ -455,7 +455,7 @@ export class DebugPanel extends SceneFeature {
         const w = this.spectrumCanvas.width;
         const h = this.spectrumCanvas.height;
         const data = state.music.frequencyData;
-        const bufferLength = data.length;
+        const bufferLength = data.length/2;
 
         ctx.clearRect(0, 0, w, h);