I pulled this image from PonoMusic's (Neil Young's long gestating digital music service) kickstarter page. It appears to compare the difference in sound quality between various digital music options, from lossy compressed downloads and streaming music to 192kHz/24bit PCM digital files.
It sure looks like the files Pono's music store will offer are going to sound a lot better than what we're used to. Young describes the difference between ordinary digital files and hi-rez digital files as "surprising and dramatic," he claims they will restore the "soul" to digital music files. From Pono's FAQ:
WILL I REALLY HEAR THE PONOMUSIC DIFFERENCE IN SOUND QUALITY?
Yes. We are confident that you will hear the difference. We're even more confident you will feel it. Everyone who’s ever heard PonoMusic will tell you that the difference is surprising and dramatic. Especially when they listen to music that they know well – their favorite music. They're amazed by how much better the music sounds – and astonished at how much detail they didn’t realize was missing compared to the original. They tell us that not only do they hear the difference; they feel it in their body, in their soul.Unfortunately, the above chart is more than a little misleading. There's no tidy way to show subjective differences in sound quality (i.e. what we actually hear as a music listener). What this chart actually shows is closer to the difference in file size between various digital music options.
There is really no argument that 192kHz/24bit music files will take up more space on your hard drive, and thus have more information in them, than CD quality (44.1kHz/16bit) files. It is likewise true that the CD quality files, even when losslessly compressed, will take up more space than MP3 or other lossy compressed files. If what you want is music files that are really large, the 192kHz/24bit FLAC files that Pono will be selling are definitely a good option.
Whether these files actually sound better than CD resolution files, or even higher bit rate encoded MP3s, is a subject of much more debate. Some listeners swear by so called "hi-rez" digital music, others say they can't hear a difference. Others go further and claim that it is not possible for humans to hear a difference between properly encoded CD quality digital and hi-rez digital, and say they have the science to back them up (I am not going to touch that one).
I never want to be in a position of telling people what they can or cannot hear, but I was curious if I could hear a difference between hi-rez digital files and CD quality files. The problem is that it is sometimes difficult to do an apples to apples comparison. Comparing a CD against a hi-rez digital file that was mastered differently does not tell us anything definitive about the virtues of higher sampling rates and greater bit depth.
In order to do a fair comparison, I downloaded the "Audiophile 96kHz/24bit" AIFF version of Stevie Wonder's Innervisions from HDTracks (this corresponds to the resolution of the middle yellow block on the chart above). This is music that I love and know very well, having listened to it in various music formats since the 1970s. I then made a CD resolution copy of my favorite track from the album, "Living For The City," using a high quality resampling program. I dropped both the "hi-rez" and CD quality files into a program called "ABXer" that allows you to do blind ABX comparisons between different music files. To make a long story short, despite my best efforts, I was unable to hear a difference between the two file resolutions. My final results were 5 correct identifications and 5 misidentifications, exactly the results one would expect if the test subject was guessing (which I was).
Despite being a dedicated music lover and someone who cares deeply about the quality of recorded sound (if not an "audiophile"), I don't think Pono is for me. Either my equipment (see details in comments) or my ears are not good enough to hear the difference. I'm not personally sold on the benefits of high-resolution music files for music listeners. I'm willing to keep an open mind about that, what I'm not willing to do is re-buy a lot of music I already own on the basis of misleading charts, nebulous promises about improved sound quality, and marketing hype.