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Thread: Our brains do not need High Resolution! (UNPROVEN ... READ ON)

  1. #21
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    Default The challenge is more enjoyment, not fewer bits.

    Quote Originally Posted by STHLS5 View Post
    I am disappointed too. It is clear there is nothing new a member can contribute for discussion in Harbeth forum. ST
    No hard feelings, but few people 7 to 8 years ago could foresee that storage costs could fall so dramatically and that technology could augment data "transport" needs through network storage, wireless and better faster internet access. Personally think the challenge today is not about getting better sound, but how to facilitate the enjoyment of music. It’s less so about amps, cd players etc

  2. #22
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    Default A technical look at the examples presented

    This should have been done by the author of the research paper. It took me about 15 minutes with standard software (Adobe Audition) and completely confirms what common sense and our own ears tell us: the classical music track is radically different in its energy and spectral content to the pop track. Consequently the entire theory proposed is built on unsafe foundations, in my opinion.

    Attached is the technical review of the classical (Beethoven) and pop (Kylie) tracks as supplied. I hope I've annotated the images to make sense of them. As you may be able to see, as far as this Beethoven example is concerned, it is clearly mono as the L & R traces (top chart) are identical. As the audition suggested, in this classical example, there is almost no energy above about 7kHz. Contast that with the Kylie which shows high level energy (red streaks) right out to the CD cut-off at 22kHz.

    All data compression systems have to walk a fine line between discarding sound to reduce bit-rate and the consequent potential loss of fidelity. These two examples would stress a coding system in very different ways: the classical piece would compress easily as it has limited loudness and limited frequency range: the pop track would be more difficult to compress because there is so much high-level energy at high frequencies ... a nightmare scenario for a compressor because to trace the high frequency waveform accurately needs more data, and that is the very thing that a compression system doesn't want to have to do!

    NOTE: This does not imply that all classical music or all Beethoven recordings have these characteristics - we have only looked at one old mono recording, the one the author used.

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    Alan A. Shaw
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  3. #23
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    Default Designing a valid test

    It appears that the author may have invalidated his own hypothesis (i.e. rendered it incapable of meaningful proof) but offering poorly-chosen samples.

    But it does beg an interesting question. How would one choose valid samples to test whether there was a difference in compressibility between pop and classical music? Both recordings should be stereo, obviously, and both should be considered to be "good quality" recordings. Beyond that, however, what would the criteria be? With a small sample size, could not any differences (assuming there were any) be ascribed to the spectral and other differences between individual recordings? Would not one have to use a fairly large number of recordings before drawing any meaningful conclusions, even assuming other variables could be equalized?

  4. #24
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    Red face "Hypothesis" means still unproven! Peer review failure ....

    Quote Originally Posted by kittykat View Post
    No hard feelings,...
    I have no hard feelings but bemused by some of the comments here. Surely, all of us are busy with no time to spare if we choose to be so.

    A cursory reading would clearly show that Robin Whittle was aware of the Beethoven audio clip was in mono. On further readings, you will find he did comparisons with all tracks in mono. He also mentioned that the original audio files were missing. Whatever it is, if one pauses for a moment and wonders why would one take Whittle statics to form a basis of Dr Hudson's hypothesis, then I wouldn't dismiss it outright.

    Whittle's compression data was the basis for another thesis by Tatung University (yes. It is ranked 1450 in the world) and also used by Nanyang University (yes, again not the best in the world). Probably there are more since this is also part of Wikipedia but I have no time to search and knowing this post is very unlikely to pass the mod.

    And how could BioMedCenter approve unsound research papers, which were peers reviewed? So we have statistics published in the 90s used by Universities and researchers like Hudson in 2010 but all of them somehow overlooked the mono track which came under scrutiny within half an hour of me posting the link here! Amazing!

    For a truly educational forum as one aspires to be then the least we can do is at least honour Hudson's request, i.e. I quote "As with all generalisations, a frank discussion of the presence of both supporting examples and counter-examples will illuminate where and why the musical information compression hypothesis breaks down".

    This article is not as much misleading when comparing the Hifi News article on Festival of sounds, which only received a mere 22 response out of the 3000 attended and yet a conclusion was drawn that all couldn't tell the difference between live and recorded.

    ST

  5. #25
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    Default Forum member confirms compression ratio

    Quote Originally Posted by EricW View Post
    ...I have noticed the same phenomenon using iTunes and Apple Lossless compression. Starting from the fixed CD data rate of 1,411 kbps, I often find that pop or rock music often compresses down to file sizes of only 800 to 1,000 kpbs, while classical music (especially with simpler instrumentation, e.g. solo piano recordings) often yields much smaller file sizes. It's an interesting phenomenom, but I suspect it's more a mathematical issue than a perceptual one.
    Quote Originally Posted by EricW View Post
    It appears that the author may have invalidated his own hypothesis (i.e. rendered it incapable of meaningful proof) but offering poorly-chosen samples......?
    In your own words classical music compresses in to smaller files than pop and rock. Isn't that good enough? Whittle spent many years to study about compression and if you go throughout the website you will find xls sheets and many other lossless classical music comparison data.

    ST

  6. #26
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    Default The beauty of old fashioned (BBC) research for the common man ...

    I think the issue here is not so much the compressability of one type of music versus another but the rather romantic hypothesis associated with the research. To quote the paper ...

    The adaptive solution to this problem of scale is information compression, thought to have evolved to better handle, interpret and store sensory data. In modern humans highly sophisticated information compression is clearly manifest in philosophical, mathematical and scientific insights. For example, the Laws of Physics explain apparently complex observations with simple rules. Deep cognitive insights are reported as intrinsically satisfying, implying that at some point in evolution, the practice of successful information compression became linked to the physiological reward system. I hypothesise that the establishment of this “compression and pleasure” connection paved the way for musical appreciation, which subsequently became free (perhaps even inevitable) to emerge once audio compression had become intrinsically pleasurable in its own right.
    etc. etc. etc.. Contrast that with the opening Summary of the BBC report ... (attached). A very different style of writing indeed.

    It reminds me of the beauty and simplicity of the BBC R&D papers from thirty years ago - attached one covering the spectral content of pop v. classical music. No romantic talk there. Just hard facts. Had I not fallen under the spell of the sublimely deceptive simplicity of these BBC papers when I was a young man, we, Harbeth, wouldn't be here today. And you wouldn't be enjoying the fruits of that BBC legacy.

    All that's required to really get to the heart of any published paper (assuming it's not smothered in obscure mathematics) is to read it from the conclusion backwards - and apply a really big dollop of good old fashioned common sense asking yourself "does that agree with my own personal experience?" If it doesn't, and you trust your ears, then you need to hunt for clues as to why the reporter - or you - are wrong.
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    Alan A. Shaw
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    Harbeth Audio UK

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