//this is all psuedotype -- not tested or anything, but hopefully it's easy enough to follow

//unity stuff
//scriptname monobehavior etc

//custom class
public class PianoKey
{
    public bool isPressed = false;
    public float pitch = 0.5f;
    public AudioSource audioSource;

    PianoKey(float Pitch)
    {
        pitch = Pitch;
    }
}


PianoKey[] pianoKeys;
PianoKeyScript[] pianoKeyScripts;

public GameObject pianoKeyPrefab;

//to use in this script, you can do something like


void Start()
{

    pianoKeys = new PianoKey[keyCount];
    for(int i = 0; i < pianoKeys.Length; i++)
    {
        //create new pianokey with specified pitch (from an array of pitches or whatever)
        pianoKeys[i] = new PianoKey(pitches[i]);

        //as i started writing this, I realized it'd be better to use a prefab and instead of having a PianoKey class in here, just create its own script for it and have it live on the prefab.
        //the prefab would have the audiosource already, and you could set up the references to the audiosource in the inspector
        //then you'd instantiate it like this

        GameObject newPianoKey = Instantiate(pianoKeyPrefab, Vector3.zero, Quaternion.identity) as GameObject;
        pianoKeyScripts[i] = newPianoKey.GetComponent<PianoKey>();

        //and since the array is an array of the monobehavior, you could do stuff like
        pianoKeyScripts[i].audio.Play();
        pianoKeyScripts[i].isPressed = true;

    }
}

void Update()
{
    for(int i = 0; i < pianoKeys.Length; i++)
    {
        if(pianoKeys[i].isPressed)
        {
            //play audio source if already not playing
            if(!pianoKeys[i].audioSource.isPlaying)
                pianoKeys[i].audioSource.Play();
        }
        else
        {
            //stop audio source if playing
            if(pianoKeys[i].audioSource.isPlaying)
                pianoKeys[i].audioSource.Stop();
        }

    }
}