Incidentally, while researching my piece on SACD, I came across a recent study in which double blind tests were conducted to determine whether people could pick between SACDs and DVD Audio discs on the one hand, and the same discs fed through a CD-standard (16/44.1) bottleneck on the other.
They could not. People could not tell the difference:
Claims both published and anecdotal are regularly made for audibly superior sound quality for two-channel audio encoded with longer word lengths and/or at higher sampling rates than the 16-bit/44.1-kHz CD standard. The authors report on a series of double-blind tests comparing the analog output of high-resolution players playing high-resolution recordings with the same signal passed through a 16-bit/44.1-kHz “bottleneck.” The tests were conducted for over a year using different systems and a variety of subjects. The systems included expensive professional monitors and one high-end system with electrostatic loudspeakers and expensive components and cables. The subjects included professional recording engineers, students in a university recording program, and dedicated audiophiles. The test results show that the CD-quality A/D/A loop was undetectable at normal-to-loud listening levels, by any of the subjects, on any of the playback systems. The noise of the CD-quality loop was audible only at very elevated levels.
The article is behind the Audio Engineering Society pay wall, but if you google a key phrase, you should be able to find it somewhere or other.
Now I imagine that there are plenty of criticisms of this study around, picking points of weakness and attempting to invalidate its results. And they may in fact be correct.
But having said that, the best way to overturn these results would be for someone to conduct a scientifically valid study which demonstrates that people can, in fact, notice the differences between formats.
Incidentally, the authors make this observation:
Though our tests failed to substantiate the claimed advantages of high-resolution encoding for two-channel audio, one trend became obvious very quickly and held up throughout our testing: virtually all of the SACD and DVD-A recordings sounded better than most CDs—sometimes much better. Had we not “degraded” the sound to CD quality and blind-tested for audible differences, we would have been tempted to ascribe this sonic superiority to the recording processes used to make them.
Why is this? They suggest — plausibly it seems to me — that the run of the mill CD release has been mixed and EQ’d for adequate performance on a wide range of mediocre equipment, whereas an SACD or DVD Audio has been created in the knowledge that the purchasers will all be careful listeners with respectable equipment, so considerable care is taken in creating the disc.
In short: buy SACD or DVD Audio where possible. It’s likely to sound better than CD, not because of high resolution digital formats, but because the recording has been prepared with love for your own fine system.