Juste une première idée, la fonction Merge (manuel p 329) :
"Merge Clipboard
This functions mixes the audio from the clipboard into the audio
selected for processing, starting at the beginning of the selection.
For this function to be available, you need to have Cut or Copied a range
of audio in the Sample Editor first.
Allows you to specify a mix ratio between the Original (the audio selected
for processing) and the Copy (the audio on the clipboard)."
