Krapp's Last Tape
In "Krapp's Last Tape" Beckett clearly instructs that the voice on the tapes be audibly different (“Strong voice, rather pompous, clearly Krapp’s at a much earlier time”) whereas in "That Time" the notes say simply, “Voices A B C are his own coming to him from both sides and above”, suggestive of the fact that these voices belong to the present time frame.