A Ginger voice is generally where a certain person has the voice which has a similar description to a Ginger person, such as:
1) Being quite loud.
2) Very prominent.
3) Very distinguishable.
4) Difficult to ignore.
Most Ginger Voice traits are ironically linked to people with ginger hair.
"Oh look here comes Harry."
"Where? I can't see him?"
"Can't you hear his Ginger Voice?"
"Ah yes, I was wondering what that noise was."
"It has the resemblence of a tortured duck, wouldn't you agree?"