unity crashing when audiosource plays on load

been looking all over the net but cant find a answer to this. when I start the game with audiosource muted there is no problem, but when the audiosource is not muted it crashes unity and i need to restart the program by force closing it. I think its my soundcheck method but i dont get why cus its only checking for the playerprefs on start/awake();

Check:

 using UnityEngine;
 using System.Collections;
 using UnityEngine.UI;
 public class Check : MonoBehaviour {
 
     public Toggle toggle;
     public string FX;
     public SoundController sc;
 
     void Start(){
         sc = GameObject.Find ("SoundController").GetComponent<SoundController> ();
         SoundCheck ();
     }
 
 
 
 
     public void SoundCheck()
     {
 
         FX = PlayerPrefs.GetString ("fx");
             
         if (FX == "enabled") {
             toggle.isOn = true;
         } else if (FX == "muted"){
             toggle.isOn = false;
         }
     }

SoundController:

 using UnityEngine;
 using System.Collections;
 
 public class SoundController : MonoBehaviour {
     public AudioClip    ScoreIncrease;
     
     public static SoundController Static ;
     public AudioSource audioSources;
     
     //public AudioSource scoreCount,bgSound ;
     
     void Start () {
         
         Static = this;
     }
     
     // Update is called once per frame
     
     public void PlayScoreIncrease()
     {
         
         swithAudioSources (ScoreIncrease);
         
     }
 
 
     void swithAudioSources( AudioClip clip)
     {
 
         audioSources.PlayOneShot(clip);
         
     }
 
 }