An Ending Can Be the First Time You Hear the Beginning
A passage can make the opening assume a new character in memory.
Some endings change the piece they finish. A song begins with unaccompanied singing. The listener hears reserve and gives the voice the benefit of a quiet setting. Much later the same passage returns after an arrangement has given the singer a great deal to carry. The note at the start of the break can now sound as if somebody has withdrawn their support, even if the first recording of the phrase has returned intact. The end has acted on an earlier event without altering its material.
This is one reason to be suspicious of asking an ending only whether it sounds final. A strong cadence can supply clarity to a work that needs it. It can also take away some of the responsibility the music gave the listener to decide what to do with the previous few minutes. An ending that refuses that clarity may let the opening live on as a question. The piece has to justify wanting that question to survive.
Where the music goes when you lose it
A fade can involve considerable precision. A repeated part remains clear early in the fade. Some component becomes hard to locate later, and the ear strains to supply it. If the composition makes that experience meaningful, the last part of the record has taught the listener what it feels like to keep hearing a thing whose material authority is going away. A fade used because a section has exhausted the available decisions can have quite a different effect. When the record starts to disappear, little of it was asking to persist.
A decisive last note can be equally strange. It can end a repeated pattern only after the ear has become ready to supply the next repetition. The listener hears that hypothetical continuation for a moment. In such a case the stop is powerful partly because the arrangement has made an unfinished thing possible. A closed form contains an audible open edge. The last note did not have to carry all of that work. The material behind it made the silence active.
It can take a second encounter to confirm that a great ending has happened. The first bars seem more knowing than they did earlier, though it is really the listener who has changed. A composer gets to use that difference by refusing to tell the audience everything a beginning contains while they are still inside it. The last sound can be the place where it becomes audible how much they have learnt to hear.