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Thread: The truth about high-resolution audio compared with std. CD 44k?

  1. #21
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    Default The CD system - the engineering reality

    Quote Originally Posted by Diminish View Post
    Last evening I read an interesting passage on the operation of a CD transport... Due to the great complexity of a CD transport, I am convinced that they would account for many of the audible differences heard between various CD players...
    Er, no! Have you allowed your preconviction that 'CD players sound different' combined with your abandoned belief that 'DACs sound different' to grasp for a second belief that 'the all important element is the CD mechanism' (I summarise).

    There may well be sonic differences between CD players - I'm not listening for them but I don't doubt that something is audible - but you are barking up the wrong tree if you think the CD mechanism is complex and hence, likely to be the source of any differences. The miracle of the CD concept (as I've discussed long ago) is not its complexity but its extreme electro-mechanical simplicity. I repeat - the Sony/Philips designers intentionally, deliberately and wholeheartedly approached the design of the discs and the players with cost minimisation (aka engineering simplicity) at the very top of the design specification. And were they proved right: absolutely. It was a wonderful collaborative effort between European and Japanese engineers who shared different cultural approaches to engineering perfection, but found a solid common ground.

    The reason is this: driven (rightly) in the early 1980s by marketing predictions of the likely consumer uptake of audio CDs (billions of discs, tens or hundreds of millions of CD player mechanisms), combined with the persistent and costly returns of mis-pressed LP records by the public, the engineers wanted a completely foolproof 'sell and forget' system. Discs that were (are) cheap to duplicate, indestructible, almost totally immune to even severe scratching and with player mechanisms that would cope with anything thrown at them. And that translated in the engineering design to the CD system's ability to cope with a huge spread of manufacturing tolerances in the discs and mechanism plus likely consumer/environmental degradation (another set of wide tolerances). So they anticipated every imaginable scenario of player and disc edge-of-tolerance: just a little bit too fast or too slow, a fresh laser or a weak one after years of use, dust on the laser, rotational bearing wear leading to non-concentric rotation, bearing oil/grease becoming sticky, laser misalignment laterally and vertically, scratches along and across the disc, disc data pits with fuzzy not sharp edges, flaking reflective CD top layer, likely power supply variation country to country, hour to hour etc. etc. etc.. In microcosm, they 'put a man on the moon and brought him back'.

    And what did they conclude? They appreciated that the entire CD player/disc system had to have built-in significant error correction and feedback systems, mechanically and electrically. And these systems themselves had to be robust and reliable, fast acting, completely transparent to the user, automatic, and that the user could not even if he wanted to, 'go manual' and bypass layers upon layers of complex interlinked self-regulating feedback control systems. And that was a genius decision. There could be no tweaking of the transport, no re-writing of the control code, no user controls other than basic play/stop/search and no possibility at all to reinterpret, reinvent or improve upon the transport system devised by the collective genius of the worlds best consumer electronics working across two continents. And that's how it stands today.

    And the consequence of superb engineering foresight was that both the discs themselves and the transport mechanisms could be punched out in sweatshop conditions without the need for a super-clean environment, using simple machinery in the hundreds of millions. No need to tweak and adjust every mechanism. Just bash them out and flog them in vast quantities. And that ensured (as Sony/Philips anticipated) that the cost of producing the mechanism would fall to little more than the cost of producing the disc, wholly unlike the LP record and its player mechanism.

    Attached is a scan from a current (and rather pricey) trade catalogue listing CD and DVD players for the PC. They sell the mechanism in a tin case to suit a PC, in a nice cardboard box with instructions, screws, audio cable etc.. Item B, cost GBP 12.95 will have a mechanism that is functionally identical to what you'll find in an audio CD system (plus lots of additional features incl. Lightscribe, ability to read and write up to 48x - CD audio is only 1 x). Item D can read BlueRay which is a far, far more complex disk to read and interpret than CD audio. It's cost, GBP 42.95. From this I suppose we can assume that the cost of the mechanism itself, made in China, can be no more than a few dollars.

    And as for 'jitter'; the implications of that certain inevitability was fully considered by the Sony/Philips designers who built-in perfectly adequate and completely robust correction systems to guarantee that it just would not be an issue at all for the consumer.

    >
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  2. #22
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    Default Watkinson's 'Law'...

    ...states that if the data is recoverable, the sound of a digital audio system is entirely dependent upon the quality of the converter sub-systems at either end of the process.

    This means that nothing happening between the two converters has any bearing at all on the sound quality, provided that the data remains 100% recoverable.

    Discuss....

  3. #23
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    Default First generation CD player v. latest ones ....

    Quote Originally Posted by A.S. View Post
    There could be no tweaking of the transport, no re-writing of the control code, no user controls other than basic play/stop/search and no possibility at all to reinterpret, reinvent or improve upon the collective genius of the worlds best consumer electronics working across two continents. And that's how it stands today.
    >
    A question, based on the above.

    From all one reads, there is a vast difference in the audio quality between the first generation of CD players from a couple of decades ago, and those of today - which themselves are sold at prices ranging from around GBP 50 to GBP 2500 or more.

    Is there anyone that has done an ABX comparison of the sound from the three types referred to above, played through a set of speakers like Harbeths/others in that category? By three, I mean a first generation CD player and two from different ends of the price ranges of today.

    I ask the question because I have read so much about how the current generation of CD players, even the budget end, are so very improved from those in the early days of CDs, which sounded sterile, flat, or whatever other audiophile expletives can be used to describe them.

    Or is this another example of high end audio marketing hype?

  4. #24
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    Default Marketing hype... essential?

    Quote Originally Posted by Kumar Kane View Post
    ...Or is this another example of high end audio marketing hype?
    To be fair ... the present global economic system shows what happens when people stop believing the marketing hype. They don't spend money. What is better? Going along with the BS only half expecting total satisfaction or the economic stagnation of not spending money at all?

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    Default Don't chase rainbows ...

    Quote Originally Posted by HUG-1 View Post
    To be fair ... the present global economic system shows what happens when people stop believing the marketing hype. They don't spend money. What is better? Going along with the BS only half expecting total satisfaction or the economic stagnation of not spending money at all?
    Long term it is certainly better in my opinion to not spend the money chasing rainbows. Yes, there will be a lot of pain while the system self corrects, but given the people v natural resources imbalance, that would the most sustainable way forward for humanity.

    That said, and human nature being what it is, I don't see that disbelief in marketing hype will last for long...pity.

  6. #26
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    Default Loss of interest in audio due to the 'nutter' element, not economics

    Quote Originally Posted by HUG-1 View Post
    ...the present global economic system shows what happens when people stop believing the marketing hype...
    I hardly think that the present global economic position is down to people no longer buying overpriced CD players! But I do believe that, in the UK at any rate, the overall loss of interest in decent domestic audio is, in significant measure, due to the 'loony toons' approach to marketing. 'Audiophile' has become a byword for a nutter who spends 100 on a cable on which 'normal' people spend 1. Or one who plays vinyl when the world has largely moved to iPods.

    Those (consumer research people) who advise manufacturers have driven domestic products into ever more stratospheric regions and come up with the hype to promote them. The reality is that there haven't been any truly significant developments, particularly in analogue design, for the last twenty years. There are very few instances of a state of the art analogue product of twenty years ago not remaining entirely satisfactory today.

  7. #27
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    Default Sound differences

    Just a very general observation/opinion triggered by this thread.

    C'mon, just a little more time and at Harbeth's you're gone tell us that all LP cartridges sound the same!
    And that it doesn't matter at all in whatever turntable and arm and on what surface.
    Because we do play the same LP grooves > but here we "can explain?" that there's also a lot of mechanics involved

    Not all sounddifferences can be explained nor ignored just by finding technical explications, as far(little) as we now know!

    Also the speakerstands, powercables, loudspeakercable and interconnects or combination's should sound all alike according to Harbeth's with very little sounddifferences.

    40 years ago general opinion was that all amplifiers with (than known specs!!) should sound the same, and......?
    .....even the amp.housing proved to be of influence on the sound

    I believe in Harbeth's sound and designs and so do a lot of people....and
    ....guess what > lot of technics, but "for us" no specs, but finetuned by a trained ear for the right sound and trust in it.

    No, IMO there are a lot of different sounding electronics, interfaces and combinations and much different pricing.
    You don't have to steal the bank, but you'll have to find your own Walhalla against your costprice!

  8. #28
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    Default Ultimate consumption and human nature

    Quote Originally Posted by HUG-1 View Post
    To be fair ... the present global economic system shows what happens when people stop believing the marketing hype. They don't spend money. ...
    If only I believed it were actually a matter of choice ...

    People aren't spending money because they have no money (or much less money) to spend. It's that simple. The reasons why this is so are manifold and complex, but the effect is simple. When your ability to spend is restricted, you tend to focus on what's essential and cut the frills. Not surprising.

    However, I don't think a change in economic circumstances has changed human nature. If we turn the corner on the current worldwide economic problems, I think things will be the same as they ever where. The fundamental question is whether we are now at a point where it's simply no longer possible to live a life based on unlimited consumption on a planet with limited and finite natural resources.

  9. #29
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    Default CD transports

    "Er, no! Have you allowed your preconviction that 'CD players sound different' combined with your abandoned belief that 'DACs sound different' to grasp for a second belief that 'the all important element is the CD mechanism' (I summarise)."

    Was this intended as a question? I have to continually remind myself that this is the HUG, albeit the "your views, not Harbeth's" section. The notion that CD players sound different is more of an axiom to me than something requiring proof and open to debate. If the above quote was intended as a question, please allow me to point out that I have not abandoned my belief that DAC's sound different. I was re-evaluating my view of the transport's contribution to the audible difference between players. You state that "The miracle of the CD concept (as I've discussed long ago) is not its complexity but its extreme electro-mechanical simplicity." Prior to this reading, I thought that the transport was SPDIF in, SPDIF out; basically just converting optical data to electronic. I was unaware of the EFM code, interveavened data, Reed-Solomon Code, and error correction that takes place prior to the generation of a SPDIF bitstream. I'm not putting it up there with the Human Genome Project, but to a layman such as myself; a CD transport is rather complex. The fact that it is an electro-mechanical process, and not simply electronic, would suggest complexity greater than that of a DAC. There is also an optical component to a transport, and data is subject to more processing in the transport than the DAC. Complexity is defined as "being characterized by a highly involved arrangement of parts, units, ect." I think that a transport meets this qualification. In fact, HUG-1, goes on to discuss the "layers upon layers of complex interlinked self-regulating feedback control systems" incorporated in a CD transport.

    Just because something is complex does not mean it is inaccurate, in fact, transports are designed for accuracy, precision, predictability, and replicability. Paradoxically, added complexity also invites a greater potential for error. This is what I was focusing on when I asserted that transports could have a greater impact on a CD player's sound quality. Bypassing a transport altogether and playing files from a computer's hard drive in their SPDIF format can and does result in improved sound quality. This view is integral to the music server and computer audio industry, and it is one where I'm in very good company. It might also be noteworthy in discussing the drop in sales of CD players.

    {Moderator's comment: factually, CD transports are elegantly simple devices. Have you looked inside one? You just can't get simpler than a motor, a spindle and a laser arm and a little processing logic. Would you like us to disassemble one to show you?}

  10. #30
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    Default Inside the CD transport

    Quote Originally Posted by A.S. View Post
    ...The miracle of the CD concept (as I've discussed long ago) is not its complexity but its extreme electro-mechanical simplicity...
    Here are some pictures of just how few parts are needed to make a CD mechanism. The three key elements are the laser arm, the motor and the means of holding the disk and/or ejecting it.

    Here is the whole shooting match. Move the mouse on this image of the laser arm to see how simple it is. The data streams right out of the laser pickup through what is probably these days just one IC. A simpler, more ecologically friendly, lower cost device for spinning a disc you cannot imagine. It is the last word in engineering efficiency, and low, low cost. Many images of the parts needed to assemble a CD/DVD transport here. Seems that the laser head is under USD1 as I commented previously. So, cut down to the very basics (small circuit board not shown) is the Philips mechanism on the attached picture. Although it doesn't have a drawer, if you were to place a CD on the spindle perhaps weighed down by a puck (as they do on fancy audiophile CD players) you will be able to play the disk and hear music. It just doesn't get simpler or more elegant than that.

    Ironically, there are more parts and greater precision of assembly required (and more cost) to make a cassette mechanism than a CD transport*. So there is definitely no correlation between engineering complexity and sound quality - perhaps the opposite is true.

    >

    *One reason: there are many feedback control systems in a CD transport to take care of wide tolerances. The cassette transport does not have such digital feedback and relies heavily on mechanical precision - which cannot be maintained over a long period due to wear and dirt etc..
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  11. #31
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    Default Digital A/B - but what were we actually comparing?

    It's hardly worthwhile to argue about the merits of the CD format any more since it won't be with us for much longer, save for the Redbook encoding standard of 16 bit / 44100 Hz. As Alan and others have pointed out, the Sony/Philips engineering team did a masterful job of designing a practical and extremely fault tolerant medium along with players that could be produced in large numbers at low cost by unskilled labor. But if you look around the developing world, you'll see that people are finding that streaming music is even cheaper and even more reliable. It takes us from the simple CD mechanism to, well, no mechanism at all once we rid ourselves of mechanical hard drives. Years before the practice became popular here in the West, I started to see taxi drivers in places like Myanmar plugging USB keys into slots on the faceplates of their car stereos. I for one am glad to see CD players disappear from the scene.

    A few months ago, a friend of mine and I set up a little demo for ourselves. We took a pair of MacBook Pros and connected them via S/PDIF (Mac notebooks have optical interfaces integrated into their headphone jacks) to a Bel Canto C5i integrated amplifier, which has dual optical inputs. We queued up the same track on both MacBooks - one was an Apple Lossless rip from Ray Charles' "Genius Loves Company" CD. The other was purchased as a 24bit/88.2kHz file from HD Tracks. We started both Macbooks at the same time, which allowed us to do some A/B tests comparing the two files. We used a pair of Mackie HR624 studio monitors connected to the Bel Canto's preamp output and listened in the nearfield*, around 8 feet from the speakers.

    We each closed our eyes and listened while the other switched inputs on the Bel Canto from one optical input to the other. The only difference we could discern was that the 24/88.2 tracks gave a us a larger mental "picture" of the performance. It was as if, by switching from one track to another, we were switching between two rooms, the 24/88.2 room about 20% larger than the 16/44.1 room.

    Could we hear the difference between 16/44.1 and 24/88.2? Yes, we could discern the difference blindfolded 100% percent of the time, but only when switching between sources.

    Could we walk into the room blindfolded and identify which version of the track was playing? Absolutely not.

    I would like to try this again, eliminating some of the variables. Among them:

    1) Were we listening to the same recording at two different resolutions, or was the 24/88.2 version remastered? Surely the "bigger room" effect we heard could be added in the mastering process.

    2) Was the 24/88.2 version simply and "uprezzed" version of the Redbook track? There have been some scandals surrounding some companies selling "HD" recordings who have been doing just that, though I don't think HDTracks has been involved. In this case, the "bigger room" effect could be a by product of the algorithms used to pad the data.

    3) We did not switch MacBooks. It is possible that variances in manufacturing of the S/PDIF interface or even the particular instance of iTunes on each machine could have introduced the difference. Another possibility is that the MacBook's S/PDIF interface behaves differently at various sample rates.

    4) We did not switch DACs. The Bel Canto was the only DAC that had dual S/PDIF ports and upamples to 24/192. The sound difference we heard could be attributed to the DAC upsampling. I now have a Wyred4Sound DAC2 that I will use to continue these tests at some point.

    Last year, I watched a demo conducted by John Atkinson using some of his own recordings. Without telling us what he was doing, he played the same recordings at a variety of sample rates, ranging from 24/88.2 all the way down to a 128mbps MP3. He played each version and after each (lower resolution) version, asked us if we heard any difference. And guess what? Not a single person in the room detected a difference in the sound!

    Something to think about...

    {Moderator's comment: * listening 8 feet from the speakers cannot be described as 'nearfield', it is 'midfield'.}

  12. #32
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    Default Comparing two digital recordings side by side

    Quote Originally Posted by jplaurel View Post
    ... We each closed our eyes and listened while the other switched inputs on the Bel Canto from one optical input to the other. The only difference we could discern was that the 24/88.2 tracks gave a us a larger mental "picture" of the performance. It was as if, by switching from one track to another, we were switching between two rooms, the 24/88.2 room about 20% larger than the 16/44.1 room....
    Wonderful experiment. I'm fascinated by how well-intentioned audio enthusiasts structure 'comparative tests'. As you say yourself, there are a number of uncontrolled variables which unfortunately leave the results open to interpretation. The most obvious one is that neither you nor I, as ordinary members of the public, have absolutely no awareness of the mysterious process of 'mastering' these recordings. We would be barred from the CD mastering facility. Their tricks and techniques are closely guarded commercial secrets. Their secret business is of increasing the appeal of recorded music. The more they sell the better so 'mastering' is an absolutely crucial step in the commercial process of bringing music from the recording studio to our homes. 'Whatever it takes' is their motto.

    How about these two recordings from last night's live concert of Rachmaninov's 3rd piano concerto. Let me set the scene: "one recording is from the standard low-bit rate feed, the other from the high bit rate feed". Can you hear the difference between them? And how would you describe the sound - especially the 'spaciousness' of the sound of the piano and hall. The volume levels are identical. These are presented here as 196kb 48kHz MP3 = very high quality. Allow time for the players to load (big files).

    Loading the player ...
    SD example

    Loading the player ...
    HD example
    Alan A. Shaw
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  13. #33
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    Default Lossless ripping - more cons than pros?

    Quote Originally Posted by jplaurel View Post
    Last year, I watched a demo conducted by John Atkinson using some of his own recordings. Without telling us what he was doing, he played the same recordings at a variety of sample rates, ranging from 24/88.2 all the way down to a 128mbps MP3. He played each version and after each (lower resolution) version, asked us if we heard any difference. And guess what? Not a single person in the room detected a difference in the sound!

    Something to think about...

    {Moderator's comment: * listening 8 feet from the speakers cannot be described as 'nearfield', it is 'midfield'.}
    All my CDs are now on a music server, ripped using Apple lossless. For sure to me, the music sounds just the same as when I play the CDs through a well specced SACD player.

    There are three penalties to doing this as compared to AAC at 128 mbps. The larger HDD to carry the files, which isn't such a big factor with costs spiraling down for the memory. Then the price one pays as the battery of the iPod runs down a lot faster when replaying lossless files. For portable listening, that can be a disadvantage. It doesn't matter at home when playing the music from a docked iPod when charging is also happening at the same time as music replay. Third, and most important, for listening via wifi across the home, the uncompressed files demand more of the wifi network than the compressed versions that can sometimes play without interruptions when the uncompressed ones may not.

    Given the above, is lossless ripping an overkill with more cons than pros?

  14. #34
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    Default Results on cheap PC speakers

    [QUOTE=A.S.;15964]

    (audio clips here, see post #32)

    I haven't got my Harbeth speakers yet (two monthes left for November shipping)... when I listen both recordings through my cheapo computer speakers:

    first recording has (relatively) less bass and more (irritating) treble; lack of dynamics; no spaciousness at all... latter one has made me feel the heaviness of the piano and I could hear the wall limits of the performance hall surprisingly, I didn't know my computer speakers are capable of producing such details.

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    Default Music streaming and lossless

    Quote Originally Posted by Kumar Kane View Post
    All my CDs are now on a music server, ripped using Apple lossless. For sure to me, the music sounds just the same as when I play the CDs through a well specced SACD player.
    For a variety of reasons, a music server can actually have superior audio quality. One reason is that a CD transport gets just one chance at sending the bits to the CD player's internal DAC. CRC failures on a damaged CD may result audible interruptions in the sound from a traditional "real time" CD player. Unlike a track ripped by computer, the CD transport cannot go back and re-read a section of data that fails a CRC check and apply an error correction algorithm. With a computer, you may be able to successfully rip a track from a surface-damaged CD that cannot be played properly with a CD player.

    Quote Originally Posted by Kumar Kane View Post
    There are three penalties to doing this as compared to AAC at 128 mbps. The larger HDD to carry the files, which isn't such a big factor with costs spiraling down for the memory. Then the price one pays as the battery of the iPod runs down a lot faster when replaying lossless files. For portable listening, that can be a disadvantage. It doesn't matter at home when playing the music from a docked iPod when charging is also happening at the same time as music replay. Third, and most important, for listening via wifi across the home, the uncompressed files demand more of the wifi network than the compressed versions that can sometimes play without interruptions when the uncompressed ones may not.

    Given the above, is lossless ripping an overkill with more cons than pros?
    No, I don't think it's overkill. As you point out, the cost of storage continues to drop. Over 10 years ago, and largely due to storage limitations, I ripped much of my collection at 128mbps. What a waste of time, as I've had to do it all over again. Lesson learned! While Apple Lossless and FLAC are indeed non-lossy formats, they are both compressed and so consume less storage space. The compression does not affect sound quality, since the files are decompressed in real time by the player. Think of lossless compression like a Zip file. When you open that Zip file, there is no loss of "fidelity" in your documents, right?

    We moved to streaming music in our house about a year ago. Once we upgraded our network from a rag-tag assemblage of junk and tangled wires to a more rationalized topology, streaming 16/44.1 lossless files wirelessly has not been a problem. We still have the occasional dropout here and there, and it's worse with 24/96 material, but in the face of the many conveniences offered by the system, it's only a minor annoyance. You can eliminate these minor dropouts completely by hardwiring your streaming device to the network. Better quality wireless routers will also make a big difference.

    There is now an option in iTunes that will convert your lossless music to 128kbps during the sync process. With this option enabled, you can enjoy lossless audio on your computer, while conserving storage space and battery power on your iDevice.

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    Default Comparison results with my wife as A/B operator

    [QUOTE=A.S.;15964]How about these two recordings from last night's live concert of Rachmaninov's 3rd piano concerto. Let me set the scene: "one recording is from the standard low-bit rate feed, the other from the high bit rate feed". Can you hear the difference between them? And how would you describe the sound - especially the 'spaciousness' of the sound of the piano and hall. The volume levels are identical. These are presented here as 196kb 48kHz MP3 = very high quality. Allow time for the players to load (big files).

    (audio clips here, see earlier post #32)

    I listened to these on my desktop system with the speakers around 76cm from my ears. @HUG-1, that would be near field, right? ;-) To me, the difference in these two files is dramatic and obvious to anyone. It's the same effect I described in my earlier post. On the "HD" file, the sound is more spacious. The hall sounds bigger.

    I just asked my lovely wife to come in and help me with a little test. She clicked randomly on one file or the other 10 times and asked me which was playing, then recorded whether I was correct or incorrect. I scored 9 out of 10 correct. Identifying them by switching A/B was very easy in a single sitting. Interestingly, my incorrect answer was the first, which leads me to ask whether I could have identified the files walking into the room stone cold with a few minutes break between attempts. In that sort of test, I expect my score would not be so good. I'll see if I can get her to help me do that test over the next day or so.

    I still believe that it would be possible to achieve the "larger room" sound of the HD file during the mastering process with a lower bitrate. For all we know, Alan's two recordings may be identical except for some DSP effects.

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    Default CD transport - a marvel of engineering

    "CD transports are elegantly simple devices. Have you looked inside one? You just can't get simpler than a motor, a spindle and a laser arm and a little processing logic. Would you like us to disassemble one to show you?"

    Thanks, but I've already seen a transport. If your purpose in showing me would be to persuade me; that a mechanism that uses 3 servos (rotational, focus, and tracking), a laser, pickup, and photo detector to read objects that are about 1/100th the size of a human hair; process, extract, and perform error correction on this data, and generate another completely separate bitstream, while maintaining picosecond time domain accuracy throughout; that this is a simple process, I'm afraid that you'd be wasting your time. I've already defined the word "complex" and admitted that far greater complexity exists. The gauge for comparison was the player's DAC; not the Mars Mission or a cassette head. Its not the parts count that accounts for complexity. I'm speaking about the volume of information that is input and output along with the transport's inherent precision, and the fact that this occurs on mechanical, optical, and electronic levels.

    There's little agreement in the audio world as to whether simplicity invariably equates to improved sonics. If I'm not mistaken, Harbeth favors comparably complex crossover designs. Most high end component manufacturers employ highly complicated power supplies with very simple analog circuits.

    Once again, I was not attributing differences in sound quality among CD players specifically to the degree of complexity within the transport. My point was that factors occurring in the generation of a SPDIF bitstream can audibly influence sound quality. Sub-optimal performance in any of the (electronic, mechanical, or optical) functions has the potential to degrade the output. This potential simply doesn't exist in the DAC (functioning only in the electronic domain). I chose to use the word "complex" to speak to the fact that a transport combines these operations. While not incorrect, in any sense, perhaps a better choice of words would be; multifarious, heterogeneous, divergent, or manifold. We are in agreement that the CD transport is a marvel of engineering, so how about if we just leave it at that?

  18. #38
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    Default

    Playing an audio disc rotating at "1 time" 1X as audio CDs do is a pathetically slow data rate of 150,000/bits sec.

    The 52X CD reader/burner in this PC has a data rate of 500,000/bits sec. Home ADSL broadband is about the same data rate down-stream.

    A typical home CAT5 network will be 100,000,000 bit/s second or thereabouts and Gigabit networks 10x faster again.

    In that context reliably reading an audio CD with a conventional laser head and motor transport is a very low technology trivial matter indeed.

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    Default Verifying CD data rate?

    "Playing an audio disc rotating at "1 time" 1X as audio CDs do is a pathetically slow data rate of 150,000/bits sec"

    I think you might have your books confused. The bitrate for Redbook CD is: (44,100 samples/sec.) x (16 bit samples) x (2 channels) = 1,411,200 bits/sec. You are citing a Wikipedia article that is talking about the Yellow Book standard for CD-ROM; indeed apples and, er, lemons. Reading directly from Ken Pohlmann's "Principles of Digital Audio", "CD-Audio is a specific application of compact disc technology; it is a standard for recording PCM audio. The CD-ROM standard is derived from the CD-Audio standard, but defines a format for general data storage." (Pohlmann, 2008, pp.276) CD-ROM/XA (eXtended Architecture) is the most efficient Yellow Book format. It has a bitrate of 1.4Mbps, the same as Redbook.
    It is important to recognize that the 1.4Mbps data rate for CD refers to the SPDIF output of a transport. The EFM coding that actually appears on the disc itself is read at 4.3218Mbps. We have to allow for the subcode, modulation, TOC data, and clock synchronization information. So, if you want to get caught up in numbers, this is well over 4 times the data rate of your CAT5 network!

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    Default More on BitRate?

    Quote Originally Posted by Diminish View Post
    "Playing an audio disc rotating at "1 time" 1X as audio CDs do is a pathetically slow data rate of 150,000/bits sec"

    I think you might have your books confused. The bitrate for Redbook CD is: (44,100 samples/sec.) x (16 bit samples) x (2 channels) = 1,411,200 bits/sec. You are citing a Wikipedia article that is talking about the Yellow Book standard for CD-ROM; indeed apples and, er, lemons. Reading directly from Ken Pohlmann's "Principles of Digital Audio", "CD-Audio is a specific application of compact disc technology; it is a standard for recording PCM audio. The CD-ROM standard is derived from the CD-Audio standard, but defines a format for general data storage." (Pohlmann, 2008, pp.276) CD-ROM/XA (eXtended Architecture) is the most efficient Yellow Book format. It has a bitrate of 1.4Mbps, the same as Redbook.
    It is important to recognize that the 1.4Mbps data rate for CD refers to the SPDIF output of a transport. The EFM coding that actually appears on the disc itself is read at 4.3218Mbps. We have to allow for the subcode, modulation, TOC data, and clock synchronization information. So, if you want to get caught up in numbers, this is well over 4 times the data rate of your CAT5 network!
    CD transfer rate is 1200kb/s or 150kB/s or 0.14MB/s.
    10base Ethernet in the 80s was at 1.25MB/s.
    Fast Ethernet in 1995 was at 12.5MB/s.

    Diminish, I have the earlier edition of Pohlmann but unable to find the info about 4.3218Mbps for EFM coding.

    ST

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