In Germany there is a thing we call "Kopfkino". It consists of two words, Kopf = Head and Kino = cinema.
The English equivalent should be daydreaming for this. Most of the time you just explore your mind or picture a certain scene different. These two scenarios happen "visually".
But sometimes I'm just having the aurally part of this experience, in which I can start a beat playing in my head or even choose a song to hear. These scenarios only happen aurally and in a focused or normal state of mind.
Is there a word or phrase for not daydreaming but some sort of "phantom hearing"?