Bit of an invalid test since the files played through both players were not-identical. The iPhone had tracks from iTunes, the Pono tracks from the Pono Store.

Any difference in loudness will give the edge to the track which is mastered at a higher volume. That's precisely why tracks are mastered to go louder - it helps sell records but unfortunately on any half decent hifi sounds like mush: http://www.leonroy.com/blog/2013/04/buying-hi-def-music-toda...

The problem is that 90% of their 2 mil song catalog is still only CD Quality (16 bit / 44.1 Khz). 256 / 320 Kbps vs. CD Quality is pretty hard to differentiate for most people. But 256 / 320 Kbps vs. 24 bit / 96 Khz should be fairly obvious.

And of course, you need a good pair of headphones.

The article keeps harping on the claim that humans cannot distinguish between 16 bit/44.1kHz and higher resolution. But the data from the author's experiment suggests the opposite: a good majority of his subjects were able to distinguish between the two resolutions. It's just that most of those picked the "wrong" one as their favorite. That's not surprising. Most people these days don't know what natural sound quality is, because all they ever listen to is recorded or grossly amplified music. As a consequence, the sharp and edgy sound of low-res audio sounds better to them than the softer and smoother high-res. That's of course a legitimate choice, but it is not a reason to dismiss high-res recordings.