Jazz is the greatest music I have ever heard in my life. GOOD = I love jazz. I've never heard any music I like better than jazz. ‎Jazz is the greatest music I had ever heard in my life. POSSIBLY INCORRECT -OR AT LEAST ODD = Jazz is (still) the best music that I had heard at some particular time in the past. ‎Jazz was the greatest music I have ever heard in my life. ODD, POSSIBLY INCORRECT = I would interpret it to mean: Jazz (which no longer exists) is better than any other music I've heard. ‎Jazz was the greatest music I had ever heard in my life. GOOD = At a particular point in the past, possibly the first time I listened to jazz, it was better than any music I had heard before that point.

I think these sentences have different meanings. If the speaker is speaking about the past then it changes "have" to "had". I want to mention the word, "that". I think sentences 1 and 4 could sound correct if, "that," is added before, "I."

#1 and #4 are correct, but mean different things. #2 and #3 are incorrect. In #1, "is" and "have ever" both are talking about "now." "Is" means right now at this moment. "Have ever" means during your whole life up to this moment. There are TWO times involved. Your birth, and right now. Let's say it is 2023 and the speaker was born in 1993. "Is" refers to 2003. "Have ever" refers to the period of time from 1993 to 2023. In #4, "was" and "had ever" both are talking about a time in the past. "Had" actually creates a reference to a second time in the past. So there are THREE times involved. The start of the speaker's life; the time right now; and a time IN THE PAST that the speaker is talking about. Perhaps the speaker first heard jazz in 2013. Then the three times would be 1993, 2013, and 2023. "Was" refers to 2013. "Had ever" refers to the period from 1993 to 2013. "Have ever" stretches to the present, 2023 "Had ever" only stretches to a point in the past, 2013. #4 means that the speaker heard jazz in 2013, and that it was the greatest music heard during the period from 1993 to 2013. It was the greatest then. But maybe it is not the greatest now. #4 suggests a possibility. Maybe things have changed since 2013. You can imagine the speaker continuing: "I first heard jazz in 2013. I thought jazz was the greatest music I had ever heard in my life. But later on, I realized that I thought hip-hop was even greater." #2 is wrong because "was" (past) doesn't go with "have ever" (present perfect). #3 is wrong because "is" (present) doesn't go with "had ever" (past perfect).