Does those better ones has higher bitrate? Source could be a factor. Could be the phone bringing out more details, and you discover new details on those songs. :)
Also better phones tend to be more revealing, and as a result, crap in, crab out, and vice versa.
Or is it a specific genre that sound good compare to others? HD598 is known in this forum for being generous and sounding great almost in every genre.
Just curious Hevan,
Do you recall if Siberia went through the same burn-in you currently experiencing in 598?