A newly recorded reading can bring an old letter into an audio programme. The listener should be able to tell that the voice belongs to a present-day reader, rather than to the historical writer.
Put that distinction before the performance begins. A simple introduction might say: “Here is a reading of the letter, performed for this episode.” Give the document’s identity and explain any cuts where those details matter.
Keep the layers audible
Consider an invented production using a letter, a reader, and added railway ambience. There are three different layers: historical words, a modern vocal performance, and a designed sound setting. Do not introduce the combined result as a recording from the station unless it actually is one.
If an excerpt has been translated, name that relationship too. Translation, adaptation, and verbatim reading are different descriptions of the work.
Try playing the introduction and first thirty seconds to someone unfamiliar with the production. Ask who they believe they are hearing and when the audio was made. A mistaken answer reveals where the framing needs work.
Carry the same explanation into the transcript and episode notes. A clear introduction allows a vivid performance to remain vivid while making its documentary status understandable.
Editorial illustration from this site’s image library; not documentary evidence of the example or object discussed.