diff --git a/js/balloons-and-static-electricity/view/BalloonRubbingSoundGenerator.js b/js/balloons-and-static-electricity/view/BalloonRubbingSoundGenerator.js
index b69b66b1..4ab5c2ab 100644
--- a/js/balloons-and-static-electricity/view/BalloonRubbingSoundGenerator.js
+++ b/js/balloons-and-static-electricity/view/BalloonRubbingSoundGenerator.js
@@ -85,7 +85,7 @@ class BalloonRubbingSoundGenerator extends NoiseGenerator {
           }
 
           // Set the output level.
-          this.setOutputLevel( MAP_DRAG_SPEED_TO_OUTPUT_LEVEL( smoothedDragVelocity.magnitude ) * options.maxOutputLevel );
+          this.setOutputLevel( MAP_DRAG_SPEED_TO_OUTPUT_LEVEL.evaluate( smoothedDragVelocity.magnitude ) * options.maxOutputLevel );
 
           // Set the pitch based on the direction in which the balloon is being dragged.
           const dragVelocity = dragVelocityProperty.value;
diff --git a/js/balloons-and-static-electricity/view/BalloonVelocitySoundGenerator.js b/js/balloons-and-static-electricity/view/BalloonVelocitySoundGenerator.js
index 4c37bcf5..1ad719c6 100644
--- a/js/balloons-and-static-electricity/view/BalloonVelocitySoundGenerator.js
+++ b/js/balloons-and-static-electricity/view/BalloonVelocitySoundGenerator.js
@@ -61,8 +61,8 @@ class BalloonVelocitySoundGenerator extends SoundClip {
         const speed = balloonVelocity.magnitude;
         if ( speed > 0 && !touchingWall ) {
 
-          const targetPlaybackRate = mapSpeedToPlaybackRate( speed );
-          const targetOutputLevel = mapSpeedToOutputLevel( speed, 0.1 ) * options.maxOutputLevel;
+          const targetPlaybackRate = mapSpeedToPlaybackRate.evaluate( speed );
+          const targetOutputLevel = mapSpeedToOutputLevel.evaluate( speed, 0.1 ) * options.maxOutputLevel;
 
           if ( !this.isPlaying ) {