Interesting. Unfortunately the audio files don't seem to be still available, I would have very much liked to have a look at them... and the only way to contact the author seems to be by comment (which again seems to essentially require an OpenID or Google login which I refuse on principle, but that's another matter).
Unlike 96/192kHz (which can actually decrease the listening fidelity, due to aliasing and/or other artefacts resulting from encoded ultrasonics) 24 bits are not inherently harmful. I.e., I would have no big problem with 48kHz/24bit.
Two aspects spring to mind with regard to the aforementioned test, though as I said, I don't have access to the test files. Firstly, we are speaking of a test set of three files. Basic statistics tell us that even when randomly choosing the 'better' file, there is still a 12.5% chance of guessing correctly three times in a row. I.e., we will have to wait for the accumulated results, which would include at least some 200 tests as I understand it.
Secondly, we are talking about classical music, which tends to be much less compressed in terms of dynamics than 'pop', rock etc. recordings. I had the misfortune of buying a recording by a rather popular metal band a few years ago that featured an effective 'dynamic range' (for want of a better word) of less than 6dB (the album in question is in fact rather infamous nowadays for its - production and in-your-face loudness, regardless of the band's cult status).
A high-quality classical recording, however, can feature a dynamic range up to 40dB and more (a grand piano alone is in theory capable of 50dB AFAIK). If the recording is normalised at -6dB peak, then this means that quiet parts can be as low as -46dB, essentially reducing the effective resolution by half. That said, these parts will still be about 50dB above the quantisation noise floor, but I find it at least plausible that the added headroom of a true 24bit recording might improve the listening fidelity.
Interestingly enough though, many proponents of 192/24 audio also claim that analog (vinyl) records are superior to CDs (Neil Young is a prime example). However, a record is actually rather limited in terms of maximum loudness compared to a CD (i.e., how much punishment the needle endures before jumping out of the track), as well as linearity, its encodable dynamics range (which is around 50dB AFAIK) and noise floor (also around -50dB AFAIK).
(Side note: a little bit of dynamic range compression is acceptable even in the case of classical material, as long as it is not overdone. The human hearing essentially does the same thing by adapting to prolonged quiet passages anyway, so it should be possible to increase the effective bit resolution by slightly reducing the dynamic range, without a noticeable change for the listener. Edit: this is effectively being done routinely as part of the mastering process AFAIK; have the test files been subjected to any mastering/mixdown at all or are they 'raw'?)
Edit (second side note): did you ever listen to classical material on a smartphone or similar mobile device (even a high-end one)? Suffice it to say that even 44.1/16 is casting pearls before swine...
Some very interesting thoughts on the subject by Monty (developer of Ogg Vorbis and Opus) can be found here.
Last edited by kalessin (24-06-2014 11:16)
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