Please take a look at the
standard advice on book search questions. Additional information would very likely help in identifying the book. Even seemingly trivial tidbits or uncertain details can trigger someone else's memory.
In this case, for example, some easy questions that might help you dredge up more details include:
- If there were two authors, was it two men, two women, or one of each? Can you remember any first letters or partial names of either author? Can you remember whether the names reminded you of anything?
- What was the process for traveling to the other world? Did it require machinery or magic, or was it simply unexplained? Did the protagonist(s) go intentionally or accidentally?
- What was the other world like? Can you remember any key differences that were mentioned? Any unique animals, physical traits of people, technological devices, or names of people, places or things?
- Was the protagonist(s) music of a specific subgenre of rock? Was anything mentioned about career, performances or specific songs?
EDIT: I see that this question was also
posted elsewhere some time ago with additional details.