Difference in Voice

First, not of the topic, but in re-watching the Launch Gameplay Trailer, I noticed that around 0:12 (when the potential-spoiler object is shown,) there’s another one of the mystery aircraft also spotted when the Chief uses his knife to stop from falling, but this time it’s escorted by two Phantoms.

Anywho, to the topic.

It seems to me that whoever says “We are Forerunners; guardians of all that exists.” and the individual claiming Humanity to be a threat to the Galaxy (Galaxies?) sound like two different individuals. Did anyone else pick up on this?

To me it just sounded like one was closer (or outside) and the other wasn’t. Other than the volume and tone of the voice, they were identical.

I must admit, I thought there was a difference at first but as KOOL AID MAN777 said, it just depends on volume and tone of the voice