How to smooth transform scaling with 2d sprite

Basically I have a sprite of a cube that reacts to the loudness of the audio playing in the scene. I want to make this a scaling smooth. I looked at .Lerp but that doesn't really work. Any help on this would be greatly appreciated.

 public AudioSource audioSource;
 public float updateStep = 0.1f;
 public int sampleDataLength = 1024;

 private float currentUpdateTime = 0f;

 public float clipLoudness;
 public float temp;
 private float[] clipSampleData;

 public GameObject sprite;
 public float sizeFactor = 1;

 public float minSize = 0;
 public float maxSize = 500;

 public void Awake()
 {
     clipSampleData = new float[sampleDataLength];
 }

 public void Update()
 {
     currentUpdateTime += Time.deltaTime;
     if (currentUpdateTime >= updateStep)
     {
         currentUpdateTime = 0f;
         audioSource.clip.GetData(clipSampleData, audioSource.timeSamples);
         clipLoudness = 0f;
         foreach (var sample in clipSampleData)
         {
             clipLoudness += Mathf.Abs(sample);
         }

         clipLoudness /= sampleDataLength;

         clipLoudness *= sizeFactor;
         clipLoudness = Mathf.Clamp(clipLoudness, minSize, maxSize);
         sprite.transform.localScale = new Vector2 (7, clipLoudness);
     }
 }