How to control audio in another scene on/off in unity - unity3d

Question

I am making a game now, it's almost done. now I am trying to control the audio on and off by button or toggle button.
The problem is, I put my audio source gameobject in the splashscreen that is in the 1st scene. and I put the audio or music button in the Setting scene which is inside the 3rd scene. I already make the c# script to control the audio but when I've tried to insert the AudioSource, but it can't since it's from a different scene. I've tried to put the AudioSource in the same scene but the audio didn't start except I go to settings scene first.
Here is the script:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
public class Music : MonoBehaviour
{
static Music instance = null;
public AudioSource Backsound;
private void Awake()
{
if (instance != null)
{
Destroy(gameObject);
}
else
{
instance = this;
GameObject.DontDestroyOnLoad(gameObject);
}
}
public void backsoundOnOff()
{
AudioSource bgsound = Backsound.GetComponent<AudioSource>();
if (bgsound.mute = true){
bgsound.mute = false;
}
else {
bgsound.mute = true;
}
}
}

Answer 1

You have already solved half the problem by using GameObject.DontDestroyOnLoad
The object does indeed exist in both scenes. Now you just need to fetch it.
In the first scene where the created the object, Change the tag of the object. Instead of using one of the exiting tags, create a new tag for it called something such as "MenuMusic". Make sure you assign it after creating it, unity does not assign it automatically
Now, in the 3rd scene, in the game object that needs to access it, create a private field "_music"
in your Start function, add
void Start() {
_music = GameObject.FindGameObjectsWithTag("MenuMusic");
}
You will now have the same instance of Music from scene 1

Answer 2

I would highly recommend referencing the sound script that you have into some sort of game manager. Usually how i work is i have one generic script that controls a multitude of options that i usually call the GameManager. This sets player controls, visual options and sound. From here you can simply set bool whether the player wants the music on and off. If this option wants to change you can reference the GameManager at any point in any script.
//Game Manager code
public void SoundControl(bool soundOff)
{
If(soundOff == true)
{
//Sound Off Control
}else
{
//Sound on Control
}
}
//Reference to game Manager
GameManager manager;
public void TurnOffSound()
{
//Turn sound off through manager
manager =
GameObject.FindGameObjectWithTag("Manager").GetComponent<GameManager>
().SoundControl(true);
}
I find this to be the easiest way to control any options through one script that you can reference anywhere.