Using AudioClip as a Matrix

Hi, im trying to use a AudioClip as a Matrix to create a new method of Audiometry test based on the khz and db, but i cant make a AudioClip matrix, can anyone help me ?

my code:

private AudioClip[ ][ ] khz;
void Start () {
khz = new AudioClip[6][11];
khz [0] [0] = Resources.Load (“250Hz-48dB”);

}

private void PlaySound (){
audSour.PlayOneShot (khz[0][0]);
}

error:
Assets/Scripts/scptAudioController.cs(22,25): error CS0029: Cannot implicitly convert type UnityEngine.AudioClip' to UnityEngine.AudioClip[ ][ ]’

how can i delete this post ? i already fix it by chaging the [ ][ ] to [,] sorry, im newbie on C# T.T