adjusting volume of soundclips with one audiosource

I'm using a SoundManager function to randomize a group of audioclips stored in an array:

 public void RandomizeSfx (params AudioClip [] clips)
 {
     int randomIndex = Random.Range(0, clips.Length);
     GetComponent<AudioSource>().pitch = Random.Range (0.95f,1.05f);
     GetComponent<AudioSource>().volume = Random.Range (0.8f, 1f);
     GetComponent<AudioSource>().clip = clips [randomIndex];
     GetComponent<AudioSource>().Play ();
 }

The SoundManager is its own GameObject with a single AudioSource attached to it.

What I want to do is to tweak the individual volumes of my audioclips. For example, one of the audioclips is louder than the rest so I want to lower just that clip by 3dB.

What would be the cleanest way to do this in Unity?

Thanks in advance.