Preserving original exports beside listening copies

[HannahMar]

The same saved music export sounds more metallic through my portable headphones. On the desk speakers I barely notice the passage, although the room is not particularly quiet. I would rather investigate before changing the source. The file is identical in both cases; I have not made a second encode or downloaded another version. I have been reading about ai audio artifact removal but I would like to rule out the playback chain before treating this as a repair problem. My first check will be any enabled equalizer. Then I can compare at a comfortable matched level. Would borrowing another pair of headphones tell me more than inspecting a picture of the sound? I can also try a different player. The aim is to locate the cause first. Which check would you put next in this sequence?