Audio Quality + Tiny Delay

The audio I'm using in my game sounds great when I preview it in the Unity Player, but going to play-mode decreases the audio quality to something like you'd hear on a 144p YouTube video.

Do I need to make separate files? Do I need to change the format of the file?

Here's the code I use, and yes, the track is an hour long... Which doesn't really make things better, does it?

 using UnityEngine;
 using System.Collections;
 
 public class PlayLengthLoop : MonoBehaviour {
 
     public AudioClip audioClip;
 
     void Start()
     {
        //Add your own times here !
        StartClip(418.500f,425.850f);
     }
 
     void StartClip(float timeStart, float timeEnd)
     {
        audio.clip = audioClip;
        audio.time = timeStart;
        audio.Play();
        StartCoroutine(DelaySoundStop(timeEnd));
     }
 
     IEnumerator DelaySoundStop(float timeEnd)
     {
        while(audio.time < timeEnd)
          yield return null;
        audio.Stop();
 
        //Add your own times here !
        StartClip(418.500f,425.850f);
     }
 }

Also, a delay happens on the track after it finishes looping, in which it loops again, but is there anyway to keep it looping without the need for a delay happening in between?