Name for this hearing disorder: one person speaks, but you hear 2 voices

There is a word describing a weird hearing anomaly. I’m looking for that word. (Meaning, this question has a factual answer, which is why I put it in GQ.)

Here is the anomaly: when a person is speaking, the person listening actually hears 2 voices. One voice has the normal pitch, and the other voice is at a different frequency, producing something that sounds like the Borg.

What is the name for this hearing issue?


You might be thinking of Diplacusis - Wikipedia