Phil has been known to have to do overdubs for the voiceovers on a phone, in the middle of nowhere, if they're editing and have an audio problem to fix. Sometimes the planned standovers get overtaken by editing decisions, and it's easier for the editors to call Phil up and have Phil read the revision aloud over the telephone. (I remember Phil mentioning this in interviews over the years, so it has happened more than once.0 There is always going to be differences in audio quality due to differences in ambient sound, equipment used, and background noises (inside versus outside, for example.)
And this is usually how the editors handle Phil's voiceovers when they decide to take out route markers from the episode in editing.
