A melody that is obvious at the start can become difficult to follow when more sounds enter. Rather than assuming it has disappeared, listen for a short piece of its shape. Choose a passage where you already know the earlier version well.
Keep a small reference in mind
Select three or four notes, a rise and fall, or a distinctive pause. You do not need to name the pitches. Hum the fragment quietly if comfortable, or draw a simple contour to remind yourself of its direction.
Replay the fuller passage and mark where that fragment remains audible. Use three labels: clear, uncertain, and not heard. “Not heard” describes your listening result; it is not proof that the part is absent from the recording.
Widen attention after the search
Listen again without actively hunting for the melody. Notice how the whole passage feels now. You may hear a relationship you missed while concentrating on a single line, or discover that the search made another layer harder to follow.
End with one concrete observation about the change in arrangement. This keeps the exercise from becoming a guessing contest about instruments and allows uncertainty to remain part of a careful, enjoyable account of what you heard.