diff --git a/node-server/assets/script.js b/node-server/assets/script.js
index 8238a91..54dcb27 100644
--- a/node-server/assets/script.js
+++ b/node-server/assets/script.js
@@ -100,10 +100,10 @@ function controlPlayback(speed) {
     }
 
     // Vitesse normalisée
-    const normalized = Math.min(speed / 100, 1);
+    const normalized = Math.min(speed / 400, 1);
     const minRate = 0.3;
     const maxRate = 1.5;
-    const playbackSpeed = minRate + (maxRate - minRate) * normalized;
+    const playbackSpeed = minRate + (maxRate - minRate) * Math.pow(normalized, 1.2);
 
     audio.playbackRate = playbackSpeed;
     vinyl.style.animationDuration = `${1 / playbackSpeed * 2}s`;