Note 3 was the loudest, but I liked the sound of S4 better of them all. It is more worm and musical. Note 3 is harsh. But all three sounded better than my S3 (Exinos with Wolfson).
And I agree with those, who praised the Adaptive Sound feature. The sound is totally different and you definitely hear more detail. I liked the simplicity of the procedure and it is done in no time at all. It doesn't adapt only to your hearing or your headset but to the ambient noise as well. It looks like it bumps up frequencies you don't hear. You may argue that in this way it distorts the sound. But you have to agree that the ambient noise distorts the sound as well by muffling some frequencies. And the obvious way to correct this is, of course, to make them louder . I think it is as simple as that. So next time when you get on a train, you go through the Adapt Sound procedure which takes 20 seconds and that is it - the sound is adapted to your ear with particular phones in particular invironment. Ingenious, isn't it? This is a must have feature on a portable music player!