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#41
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CD player quality recommendation
"Colin B." wrote in
message Arny Krueger wrote: "Colin B." wrote in message Plugged the DVD player into the preamp, burned a copy of Kind of Blue, and compared it very informally to my Denon DCM-340. First thing I noticed is that (since I didn't have any way of adjusting levels, although I could have measured them) when there were drums or trumpet playing, the DVD player was louder. You know this is really sad. You may be bright enough that you seem to realize that your listening test might not be worth squat unless you adjusted the levels of the two players within 0.1 dB. Arny, I have defended DBT to the n'th degree. Mere words with no actions to back them up. I've agreed ad nauseum on the criticality of proper testing and the existence of listener bias. Lip service. Thus, please allow me to offer the following advice. **** OFF! Take a valium. Take two! Wipe the spittle off your chin, and then come back and reread my post. This childish language just goes to show how immature and irrational you are. Nowhere did I mention the word "test" in my post, except at the end. You're just playing with words. This was an evening of playing. This was entertainment. This was interest. This was at the VERY most, a way of deciding for myself if I should pursue real testing methodology. You're just defending doing some stupid stuff and then extensively bragging about it in public. You say you have the means to match levels, which I might doubt but I'll take what you say at face value. You misread. I said that I do NOT have the means to match levels--only to measure them. A test-tone CD and an oscilloscope (or even a good DVM, for that matter) should accomplish that quite nicely. Matching them is another matter altogether of course, and neither player has an output level adjustment. Adding external volume controls isn't rocket science. It's not even very costly. Nevertheless you just launched into a long rambling dissertation about what you thought you heard, when your listening test is obviously, grotesquely and fundamentally flawed. Well yes, that was sort of the point. Again I'll point out that this wasn't a test. You're dissembling. You're lazy, both practically and intellectually. |
#42
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CD player quality recommendation
Wow.
I'm speechless. Congratulations Arny. You win. |
#43
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CD player quality recommendation
"DaveL" AKA Snake wrote in message . .. Actually I did hear of the mod from several sources. I did not do a before and after test but I can tell you that this unit sounds really good and far better than my Yamaha unit. If you believe that they all sound the same then go ahead and keep your head (or ears) in the sand. How many audiophiles are spending thousands on high end cd players and separate dacs? I guess they are all wasting their money when they could have done like you and bought the cheapest no name unit and had the same sound. Or they could have bought a cheapish player and spent the difference on better speakers, giving a *FAR* greater improvement. The reason they don't is ignorance, or the desire for something *other* than a sonic improvement. (eg. bragging rights) If you believe that all cd players have a perfectly flat frequency response and virtually no distortion then you are simply ignorant to the truth. If you believe you can really hear the minute differences in any *competent* player, then you should do a double blind reality check. OTOH, anyone can hear the differences between speakers. Put your money where it does some *actual* good, or throw it away, it's your choice. MrT. |
#44
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CD player quality recommendation
"Colin B." wrote in
message Wow. I'm speechless. Congratulations Arny. You win. I'm not here to win. I'm here to wake you up. |
#45
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CD player quality recommendation
On Fri, 4 Nov 2005 08:47:31 -0800, "DaveL" AKA Snake wrote:
Hi Arny, All I know is what my ears tell me. But your measurements prove my point. None of the analog output specs are the same. They all vary. This means the all sound a little bit different. Utter rubbish. These variations are *way* below the threshold of audibility. The difference may be slight but it is still there. It could be like Stewart says that the newer players have less variance. I can accept that. But please believe me that my Denon does sound better than my Yamaha. This is no lie or misjudgment. I'm sure you are not *deliberately* failing to tell the truth. I'm equally sure that what you're saying is hogwash, as Arny has pointed out. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#46
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CD player quality recommendation
"Colin B." wrote in message ... Quick question for the techies out there. Are there any currently available CD or DVD players out there which are audibly flawed? Wow, lot of nasty sniping going on here. From my own viewpoint and from various non-scientific experiementation I've done personally, I find there are a number of things that can influence CD sound quality. The digital info basically goes into a receiver chip, then through a DAC, then through an opamp. Any one of these (plus all the other assorted filtering components, wire traces, RF interferece, etc.) can vary the sound. I am using an aging dual 18-bit mono DAC setup that's more than 10 years old and it sounds excellent. I have upgraded the op-amp to one which has better specs. From what I have read (and I have read a fair amount about it) the op-amp and capacitors used in the audio stage of the DAC and/or CD transport play a far greater role than the DACs themselves... for example I use a new (1yr old) decent quality DVD player as my CD, HDCD, and MP3 transport. This sucker has 24-bit/96KHz DACs (actually probably a stereo dual DAC given the price). A side-by-side comparison with my external DAC shows that the sound quality sucks compared to the older external DAC which was built with MUCH MUCH higher quality components in the output stage. There's just no comparison. When you spend more money on a CD/DVD player, generally speaking they are built with higher quality components in the audio stage, ONE of which is the DAC. You can and do have crap-quality players out there with fancy DAC chips. You are also paying for R&D to design the circuit in such a way to minimize different types of interference, be it by adding decoupling caps, filtering and/or regulating the power supply, locating components which may interfere with each other as far from each other as possible, etc. Unless you are lucky enough to find a sound equipment dealer with a listening room who is willing to set up side-by-side comparisons for you (think higher-end stuff), you are always shooting in the dark somewhat when purchasing a component. Spend as much as you can afford, do your research, and hopefully you come home with something you can live with for a few years. One last thing: sound quality is subjective. Yeah, yeah, there are ways to measure the purity of the output, but what it comes down to is this: you either like the sound or you don't. One person's "better" may be another's "worse". Just my 2 cents Dave |
#47
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CD player quality recommendation
Dave wrote:
"Colin B." wrote in message ... Quick question for the techies out there. Are there any currently available CD or DVD players out there which are audibly flawed? Wow, lot of nasty sniping going on here. From my own viewpoint and from various non-scientific experiementation I've done personally, I find there are a number of things that can influence CD sound quality. The digital info basically goes into a receiver chip, then through a DAC, then through an opamp. Any one of these (plus all the other assorted filtering components, wire traces, RF interferece, etc.) can vary the sound. I am using an aging dual 18-bit mono DAC setup that's more than 10 years old and it sounds excellent. I have upgraded the op-amp to one which has better specs. From what I have read (and I have read a fair amount about it) the op-amp and capacitors used in the audio stage of the DAC and/or CD transport play a far greater role than the DACs themselves... for example I use a new (1yr old) decent quality DVD player as my CD, HDCD, and MP3 transport. This sucker has 24-bit/96KHz DACs (actually probably a stereo dual DAC given the price). A side-by-side comparison with my external DAC shows that the sound quality sucks compared to the older external DAC which was built with MUCH MUCH higher quality components in the output stage. There's just no comparison. When you spend more money on a CD/DVD player, generally speaking they are built with higher quality components in the audio stage, ONE of which is the DAC. You can and do have crap-quality players out there with fancy DAC chips. You are also paying for R&D to design the circuit in such a way to minimize different types of interference, be it by adding decoupling caps, filtering and/or regulating the power supply, locating components which may interfere with each other as far from each other as possible, etc. Unless you are lucky enough to find a sound equipment dealer with a listening room who is willing to set up side-by-side comparisons for you (think higher-end stuff), you are always shooting in the dark somewhat when purchasing a component. Spend as much as you can afford, do your research, and hopefully you come home with something you can live with for a few years. One last thing: sound quality is subjective. Yeah, yeah, there are ways to measure the purity of the output, but what it comes down to is this: you either like the sound or you don't. One person's "better" may be another's "worse". Just my 2 cents In which case, if one is taking the digital data stream via optic from the CD player does it matter at all as to its quality as long as it gets the data off the disc? -- Dirk The Consensus:- The political party for the new millenium http://www.theconsensus.org |
#48
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CD player quality recommendation
"Dirk Bruere at Neopax" wrote in message ... In which case, if one is taking the digital data stream via optic from the CD player does it matter at all as to its quality as long as it gets the data off the disc? Yes and no. Your digital filter, dac, and analog output stages all impact the final output, but they all work with the same 16-bit, 44kHz source. Any CD transport with equivalent quality output will read and output the same info. That having been said, cheaper transports and/or DVD/CD players tend to have equally cheap, non-decoupled, nonregulated power supplies, poor circuit components and/or design, which (and that's not the whole list) may add unwanted digital noise or corruption to the output stream. So in that regard not all transports are created equal. There are reasons why people might pay $9,000 for a Krell CD transport or high-end DAC... I don't claim to be able to tell the difference (nor have that kind of cash to lay out on a CD transport) but I CAN tell the difference between a poorly designed, poorly executed digital source and a well-designed, well-built one. I guess it all boils down to what your standards are. I will grant you, a $100 Sony or Panasonic CD player will sound pretty good next to a cassette tape. The difference in fidelity is HUGE and painfully obvious even to the most tone-deaf listener. Not so with digital audio, where the unwanted background noise has been virtually eliminated. Most people get used to hearing what comes out of their stereo. If they've only ever had a lower-end model, then that's what they expect and, as such, are not unhappy with the output. BUT, sit that big middle demographic down with a side-by-side comparison with a higher-end system and they'll hear the difference. Whether they're willing to pay for it is personal choice. Dave |
#49
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CD player quality recommendation
Dave wrote:
"Dirk Bruere at Neopax" wrote in message ... In which case, if one is taking the digital data stream via optic from the CD player does it matter at all as to its quality as long as it gets the data off the disc? Yes and no. Your digital filter, dac, and analog output stages all impact the final output, but they all work with the same 16-bit, 44kHz source. Any CD transport with equivalent quality output will read and output the same info. That having been said, cheaper transports and/or DVD/CD players tend to have equally cheap, non-decoupled, nonregulated power supplies, poor circuit components and/or design, which (and that's not the whole list) may add unwanted digital noise or corruption to the output stream. So in that regard not all transports are created equal. There are reasons why people might pay $9,000 for a Krell CD transport or high-end DAC... I don't claim to be able to tell the difference (nor have that kind of cash to lay out on a CD transport) but I CAN tell the difference between a poorly designed, poorly executed digital source and a well-designed, well-built one. I guess it all boils down to what your standards are. I will grant you, a $100 Sony or Panasonic CD player will sound pretty good next to a cassette tape. The difference in fidelity is HUGE and painfully obvious even to the most tone-deaf listener. Not so with digital audio, where the unwanted background noise has been virtually eliminated. Most people get used to hearing what comes out of their stereo. If they've only ever had a lower-end model, then that's what they expect and, as such, are not unhappy with the output. BUT, sit that big middle demographic down with a side-by-side comparison with a higher-end system and they'll hear the difference. Whether they're willing to pay for it is personal choice. I was really thinking about CD data ripped in .wav to HDDs. PC CDROM drives are about as cheap as you can get. I haven't noticed any difference in quality of final output. Would one really see differences in data between different CDROM drives? -- Dirk The Consensus:- The political party for the new millenium http://www.theconsensus.org |
#50
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CD player quality recommendation
"Dirk Bruere at Neopax" wrote in message ... I was really thinking about CD data ripped in .wav to HDDs. PC CDROM drives are about as cheap as you can get. I haven't noticed any difference in quality of final output. Would one really see differences in data between different CDROM drives? You make a good point. The answer, of course, is No. Even one bit out of place could make a data cd useless. I believe that you can dub cd's to hard drive with no loss of quality, but then I believe in the Great Pumpkin, too. Your question is beyond the scope of my abilities... I am pretty sure that noise on the digital line has GOT to affect the sound quality... why this does not affect the ability of a PC to correctly read data I do not know. Maybe somebody can help me out here.... DAve |
#51
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CD player quality recommendation
In article mR8ef.108238$y_1.4778@edtnps89,
Dave wrote: I was really thinking about CD data ripped in .wav to HDDs. PC CDROM drives are about as cheap as you can get. I haven't noticed any difference in quality of final output. Would one really see differences in data between different CDROM drives? You make a good point. The answer, of course, is No. Even one bit out of place could make a data cd useless. I believe that you can dub cd's to hard drive with no loss of quality, but then I believe in the Great Pumpkin, too. Your question is beyond the scope of my abilities... I am pretty sure that noise on the digital line has GOT to affect the sound quality... why this does not affect the ability of a PC to correctly read data I do not know. Maybe somebody can help me out here.... Well, there are several different issues involved here. As far as "ripping" and CD-ROM drives are concerned - the issues are those of proper reading from the disc itself (e.g. accurate Red Book audio CD error detection, error correction, and concealment) and audio block-address accuracy (what's often misleadingly called "jitter"). These days, any high-quality CD-ROM drive ought to be able to read the Red Book data from the disc accurately, applying the Red Book C1/C2 Reed-Solomon error correction coding, and doing error concealment (interpolation or muting) to "hide" any errors which are too severe for proper error correction. I have seen some drives (older ones, mostly) which fouled this process up pretty badly - they didn't do adequate C1/C2 error correction/concealment of digital audio data, or suffered from really severe block-addressing inaccuracy (bad "jitter"). Many CD "ripping" packages have the ability to read each section of the disc multiple times and compare the result... a good way to catch uncorrected or badly-concealed errors and retry the reads until the drive delivers the data correctly. With a decent CD-ROM drive and good ripping software, you should get data that is essentially error-free. Further processing won't care which drive the data came from. Transports and DACs involve a different set of issues. The transport plays through the data once, applying the Reed/Solomon error-correction coding and de-interleaving, and then packages the data up in S/PDIF data frames and sends them to the external DAC-box. The DAC-box must receive the S/PDIF data, and: [1] Extract the data, [2] Recover a clock signal, and [3] Check the parity in each block, and [4] Feed the data, and a clock signal, are then fed to the DAC chip (or a digital filter which preceeds it) for conversion to analog. The trickiest part of this problem involves the clock signal. S/PDIF does not have a distinct clock signal on a separate set of conductors. Instead, the clocking is "embedded" in the data - the S/PDIF receiver must reconstruct a clock signal based on the transition times of the data signal. This is usually done by the S/PDIF receiver chip, using a phase-locked loop circuit of some sort. Many external DAC-boxes simply feed this clock signal from the PLL right into the DAC chip or digital filter. This is the commonest approach, I believe, and it's not a good one. Timing or amplitude imprecision in the clocking (jitter) can induce errors in the reconstructed analog audio waveform... they're measurable, and in some cases they may very well be audible. This is one area in which the presence of noise on a digital signal can have an effect on the analog signal. Better-design DAC boxes do a better job of creating a stable timing signal for the DAC-chip to use when converting digital samples to analog. This may be done by using multiple stages of phase-locked loop (filtering out the jitter), or by buffering the digital samples through "deep" first-in, first-out FIFO buffer and using a stable quartz-crystal oscillator to clock the signals out of the FIFO into the DAC, or by using an asynchronous sample-rate converter to resample the data stream before feeding it into a crystal-oscillator-timed DAC. This is one of the areas in which the market, and its perceptions, can be a bit backwards from reality. Some DAC-boxes have a reputation for "revealing" the differences between different transports, and this is often touted as a good and impressive characteristic. I see it otherwise... a good DAC-box should be entirely immune to timing jitter, noise on the S/PDIF signal, etc., and should always sound at its best. DAC-boxes which "reveal" transport-related differences in the S/PDIF signal are, I think, showing that their clock recovery circuits are not robustly designed. Single-box CD players (potentially less expensive than transport/DAC combinations) don't have the S/PDIF clock-recovery problem at all - they're immune to this particular problem. A single-box player runs its internal DAC from a stable quartz-crystal oscillator, not from a clocking signal recovered from the disc or data. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
#52
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CD player quality recommendation
On Mon, 14 Nov 2005 22:31:36 GMT, "Dave"
wrote: "Dirk Bruere at Neopax" wrote in message ... In which case, if one is taking the digital data stream via optic from the CD player does it matter at all as to its quality as long as it gets the data off the disc? Yes and no. Your digital filter, dac, and analog output stages all impact the final output, but they all work with the same 16-bit, 44kHz source. Any CD transport with equivalent quality output will read and output the same info. That having been said, cheaper transports and/or DVD/CD players tend to have equally cheap, non-decoupled, nonregulated power supplies, poor circuit components and/or design, which (and that's not the whole list) may add unwanted digital noise or corruption to the output stream. So in that regard not all transports are created equal. There are reasons why people might pay $9,000 for a Krell CD transport or high-end DAC... I don't claim to be able to tell the difference (nor have that kind of cash to lay out on a CD transport) but I CAN tell the difference between a poorly designed, poorly executed digital source and a well-designed, well-built one. Actually, if true (which is doubtful) that would simply indicate that you have a really poor DAC. I have not in about fifteen years now seen any digital output which had such poor performance that it was *audibly* different when used with a decent DAC. It is the DAC which is utterly critical here, not the transport. Use a properly designed DAC such as the impeccable Benchmark DAC-1, and transport 'quality' is quite simply irrelevant. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#53
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CD player quality recommendation
On Mon, 14 Nov 2005 23:12:18 GMT, "Dave"
wrote: "Dirk Bruere at Neopax" wrote in message ... I was really thinking about CD data ripped in .wav to HDDs. PC CDROM drives are about as cheap as you can get. I haven't noticed any difference in quality of final output. Would one really see differences in data between different CDROM drives? You make a good point. The answer, of course, is No. Even one bit out of place could make a data cd useless. I believe that you can dub cd's to hard drive with no loss of quality, but then I believe in the Great Pumpkin, too. Your question is beyond the scope of my abilities... I am pretty sure that noise on the digital line has GOT to affect the sound quality... why this does not affect the ability of a PC to correctly read data I do not know. Maybe somebody can help me out here.... Sure, no problem. Your certainty has no basis in fact. The whole *point* of digital signal transmission is that, unless it is so big that it causes bits to be dropped, noise on the datastream makes absolutely *zero* difference to the reconstructed analogue signal, given a properly designed digital to analogue conversion system, aka DAC. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#54
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CD player quality recommendation
Stewart Pinkerton wrote:
On Mon, 14 Nov 2005 23:12:18 GMT, "Dave" wrote: "Dirk Bruere at Neopax" wrote in message ... I was really thinking about CD data ripped in .wav to HDDs. PC CDROM drives are about as cheap as you can get. I haven't noticed any difference in quality of final output. Would one really see differences in data between different CDROM drives? You make a good point. The answer, of course, is No. Even one bit out of place could make a data cd useless. I believe that you can dub cd's to hard drive with no loss of quality, but then I believe in the Great Pumpkin, too. Your question is beyond the scope of my abilities... I am pretty sure that noise on the digital line has GOT to affect the sound quality... why this does not affect the ability of a PC to correctly read data I do not know. Maybe somebody can help me out here.... Sure, no problem. Your certainty has no basis in fact. The whole *point* of digital signal transmission is that, unless it is so big that it causes bits to be dropped, noise on the datastream makes absolutely *zero* difference to the reconstructed analogue signal, given a properly designed digital to analogue conversion system, aka DAC. So can we conclude, for CD players, that the only (or major?) reason for differences in price are due to the DACs? -- Dirk The Consensus:- The political party for the new millenium http://www.theconsensus.org |
#55
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CD player quality recommendation
"Colin B." wrote in
message Quick question for the techies out there. Are there any currently available CD or DVD players out there which are audibly flawed? Typically, audible flaws are due to the player being broken or having some fairly gross design issues. There are also some degenerate classes of CD players such as the CD ROM drives in computers with analog outputs and/or headphone jacks, and cost-effective portables. From all I've heard, CD players seem to have hit essential perfection a few years ago. I've been considering getting a replacement for my ancient (i.e. ~16 years old) player, but want to do some listening first, to see how important it is in the grand scheme of things. One approach is to buy a modestly-priced *universal* player such as the Pioneer DV 588 . However, the only modern CD player I have available is a no-name DVD player (matsumagna****asonic or some such thing). The worst problem I've had with these is that they don't last. I got less than 18 months out of the last two no-name DVD players I bought, and they were used very lightly. In contrast I have a Pioneer DV 525 that has got to be 5-6 years old, and does yoeman duty for both audio and video. I have to admit that I rip a lot more CDs than I listen to directly, and most of the CDs I listen to directly are CD's I produced from live performances. Can I count on something this cheap to be audibly nonexistent, or am I going to have to borrow at least a name-brand item from someone? If you have a PC with a pretty good sound card, you could run the freebie AudioRightmark on your player via a CD-R of their test data, and see how yours works. Unless you have something special in the way of a sound card (i.e., a AP 24192 or LynxTwo) the player will probably outperform your sound card. But if the sound card is good, you'll know the player is at least that good. |
#56
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CD player quality recommendation
"Dirk Bruere at Neopax" wrote in
message So can we conclude, for CD players, that the only (or major?) reason for differences in price are due to the DACs? Not at all. The major reason for differences in price are parts of the player other than the audio signal chain from converter out. IOW, the case, the display, the transport, the buttons, the image, etc. The signal path from the converter out has a parts cost of about $3 for a top-quality well-engineered player, and much less for a real cheapie. This translates into a cost-justified consumer price increase of no more than $20. I find that there still be be significant differences in sound quality due to things like ability to track difficult media. One leading common source of difficult media is home-burned CDs. The degree to which light mistracking can be confused with problems in the analog domain may surprise many. |
#57
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CD player quality recommendation
"Harry Lavo" wrote in message
"Arny Krueger" wrote in message ... "Colin B." wrote in message snip Nevertheless you just launched into a long rambling dissertation about what you thought you heard, when your listening test is obviously, grotesquely and fundamentally flawed. Not given to overstatement, are you Arny? No, I was understating the problem. |
#58
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CD player quality recommendation
"Dave Platt" wrote in message ... .. The trickiest part of this problem involves the clock signal. S/PDIF does not have a distinct clock signal on a separate set of conductors. Instead, the clocking is "embedded" in the data - the S/PDIF receiver must reconstruct a clock signal based on the transition times of the data signal. This is usually done by the S/PDIF receiver chip, using a phase-locked loop circuit of some sort. Is there some "raw" format which bypasses the S/PDIF and it's inherent clocking limitations which could be output to a redesigned external DAC? Maybe I2S? I mean, if it's the S/PDIF encoding/decoding which introduces clock error (and hence "jitter") hasn't anyone said "there's got to be a better way"? I am thinking not, as everybody seems to be trying to build a better S/PDIF-based (external) DAC. But hypothetically, if a transport output both the datastream AND a clock signal in realtime instead of packaged in frames requiring decoding at the receiving end... well, why not? Single-box CD players (potentially less expensive than transport/DAC combinations) don't have the S/PDIF clock-recovery problem at all - they're immune to this particular problem. A single-box player runs its internal DAC from a stable quartz-crystal oscillator, not from a clocking signal recovered from the disc or data. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
#59
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CD player quality recommendation
In article n%mef.112190$y_1.66453@edtnps89,
Dave wrote: "Dave Platt" wrote in message ... . The trickiest part of this problem involves the clock signal. S/PDIF does not have a distinct clock signal on a separate set of conductors. Instead, the clocking is "embedded" in the data - the S/PDIF receiver must reconstruct a clock signal based on the transition times of the data signal. This is usually done by the S/PDIF receiver chip, using a phase-locked loop circuit of some sort. Is there some "raw" format which bypasses the S/PDIF and it's inherent clocking limitations which could be output to a redesigned external DAC? Maybe I2S? I mean, if it's the S/PDIF encoding/decoding which introduces clock error (and hence "jitter") hasn't anyone said "there's got to be a better way"? I am thinking not, as everybody seems to be trying to build a better S/PDIF-based (external) DAC. But hypothetically, if a transport output both the datastream AND a clock signal in realtime instead of packaged in frames requiring decoding at the receiving end... well, why not? From what I recall, I'm fairly sure that there have been some transports made which generated I2S, and some DACs made which would accept it. This of course requires a different cabling arrangement... the setups I remember used mini-DIN connectors and cables, the same as are used for S-Video. Using this approach decreases the clocking problems, but doesn't eliminate them entirely. You've still got the master oscillator (which is a quartz-crystal type) sitting in the transport box, being sent over a transmission line to the DAC box. Ground loops, noise, etc. can still get into the clock on its way to the digital filter and DAC chip and mess up the conversion to some extent. Another way to do this is to reverse the direction of the clocking. Put the quartz-crystal oscillator in the DAC box, and feed its (clean, low-jitter, well-shielded) signal directly to the filter/DAC-chip. The clock signal would also be buffered, and transmitted down the clock line in the multi-conductor cable to the transport. The transport would then slave itself to this clock signal, feeding the bits up the cable to the DAC-box under control of the external clock. This approach pretty much replicates, in a two-box system, the clock distribution strategy used in a single-box CD player. The DAC chip itself is fed from the cleanest and most stable clock in the system, and the transport is slaved to this clock (rather than the other way around). I don't know whether anyone has built a transport / DAC-box product line using this approach. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
#60
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CD player quality recommendation
On Tue, 15 Nov 2005 15:18:43 GMT, "Dave"
wrote: "Dave Platt" wrote in message ... . The trickiest part of this problem involves the clock signal. S/PDIF does not have a distinct clock signal on a separate set of conductors. Instead, the clocking is "embedded" in the data - the S/PDIF receiver must reconstruct a clock signal based on the transition times of the data signal. This is usually done by the S/PDIF receiver chip, using a phase-locked loop circuit of some sort. Is there some "raw" format which bypasses the S/PDIF and it's inherent clocking limitations which could be output to a redesigned external DAC? Maybe I2S? I mean, if it's the S/PDIF encoding/decoding which introduces clock error (and hence "jitter") hasn't anyone said "there's got to be a better way"? I am thinking not, as everybody seems to be trying to build a better S/PDIF-based (external) DAC. But hypothetically, if a transport output both the datastream AND a clock signal in realtime instead of packaged in frames requiring decoding at the receiving end... well, why not? It's called SDIF-2, has separate master clock and data lines, and has been used in the recording industry for decades. However, the existence of top-class sample-rate converting DACs like the Benchmark render the use of this standard moot for home listening. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#61
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CD player quality recommendation
On Tue, 15 Nov 2005 11:01:14 +0000, Dirk Bruere at Neopax
wrote: Stewart Pinkerton wrote: On Mon, 14 Nov 2005 23:12:18 GMT, "Dave" wrote: "Dirk Bruere at Neopax" wrote in message ... I was really thinking about CD data ripped in .wav to HDDs. PC CDROM drives are about as cheap as you can get. I haven't noticed any difference in quality of final output. Would one really see differences in data between different CDROM drives? You make a good point. The answer, of course, is No. Even one bit out of place could make a data cd useless. I believe that you can dub cd's to hard drive with no loss of quality, but then I believe in the Great Pumpkin, too. Your question is beyond the scope of my abilities... I am pretty sure that noise on the digital line has GOT to affect the sound quality... why this does not affect the ability of a PC to correctly read data I do not know. Maybe somebody can help me out here.... Sure, no problem. Your certainty has no basis in fact. The whole *point* of digital signal transmission is that, unless it is so big that it causes bits to be dropped, noise on the datastream makes absolutely *zero* difference to the reconstructed analogue signal, given a properly designed digital to analogue conversion system, aka DAC. So can we conclude, for CD players, that the only (or major?) reason for differences in price are due to the DACs? No, the differences in price are down to what the marketing department thinks the market will bear. Manufacturing costs are down to the DAC chips, the complexity of the output stage, and the number and complexity of the power supplies. In many 'designer label' cases (pun intended), the above costs are totally outweighed by the cost of the inch-thick laser-etched alloy casework, and wafer-thin heavily damped loading mechanism (or even fancier top-loading arrangement). The actual transport mechanism which retrieves the information from the disc, will cost about $20 in every case. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
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CD player quality recommendation
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CD player quality recommendation
"Dave" wrote in message
news:n%mef.112190$y_1.66453@edtnps89 "Dave Platt" wrote in message ... The trickiest part of this problem involves the clock signal. S/PDIF does not have a distinct clock signal on a separate set of conductors. Instead, the clocking is "embedded" in the data - the S/PDIF receiver must reconstruct a clock signal based on the transition times of the data signal. This is usually done by the S/PDIF receiver chip, using a phase-locked loop circuit of some sort. Is there some "raw" format which bypasses the S/PDIF and it's inherent clocking limitations which could be output to a redesigned external DAC? Maybe I2S? I mean, if it's the S/PDIF encoding/decoding which introduces clock error (and hence "jitter") hasn't anyone said "there's got to be a better way"? I am thinking not, as everybody seems to be trying to build a better S/PDIF-based (external) DAC. But hypothetically, if a transport output both the datastream AND a clock signal in realtime instead of packaged in frames requiring decoding at the receiving end... well, why not? The industry took a more direct route. They routinely and inexpensively implement digital gear that accepts the so-called "flawed" SP/DIF signal and produce exceedingly clean analog signals. |
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CD player quality recommendation
"Arny Krueger" writes:
snip I find that there still be be significant differences in sound quality due to things like ability to track difficult media. One leading common source of difficult media is home-burned CDs. The degree to which light mistracking can be confused with problems in the analog domain may surprise many. Hmm, the only CDs I have serious problems with are CDs I have bought. My home-brewn LP-CD 'products' have never caused me any problems. I am actually considering clone one of my problems CD to be able to listen to the last tracks on my stereo. -- ================================================== ====================== Martin Schöön "Problems worthy of attack prove their worth by hitting back" Piet Hein ================================================== ====================== |
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CD player quality recommendation
"Dave Platt" wrote in message ... In article mR8ef.108238$y_1.4778@edtnps89, Better-design DAC boxes do a better job of creating a stable timing signal for the DAC-chip to use when converting digital samples to analog. This may be done by using multiple stages of phase-locked loop (filtering out the jitter), or by buffering the digital samples through "deep" first-in, first-out FIFO buffer and using a stable quartz-crystal oscillator to clock the signals out of the FIFO into the DAC, or by using an asynchronous sample-rate converter to resample the data stream before feeding it into a crystal-oscillator-timed DAC. I am confused as to how all these various clocks interact. For example in my external DAC I've got a receiver chip (CS8412) which has its' own master clock pin (MCK), a voltage-controlled oscillator which is part of the PLL. This clock can be an input or output externally. The only outputs from my receiver are the serial clock (SCK), word clock (FSYNC) and serial data (SDATA). These go into an 8x oversampling digital filter (YM3433) which ALSO has a clock (in fact an external 10MHz crystal oscillator). Outputs are then DATA-R, DATA-L, word clock out (WCO) and bit clock out (BCO) which are fed, respectively, to two DACs (AD1860's). How do the digital receiver and digital filter clocks interact? What's the relationship between these clocks and the clock in the transport? |
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CD player quality recommendation
I am confused as to how all these various clocks interact. For example in
my external DAC I've got a receiver chip (CS8412) which has its' own master clock pin (MCK), a voltage-controlled oscillator which is part of the PLL. This clock can be an input or output externally. The only outputs from my receiver are the serial clock (SCK), word clock (FSYNC) and serial data (SDATA). These go into an 8x oversampling digital filter (YM3433) which ALSO has a clock (in fact an external 10MHz crystal oscillator). Outputs are then DATA-R, DATA-L, word clock out (WCO) and bit clock out (BCO) which are fed, respectively, to two DACs (AD1860's). How do the digital receiver and digital filter clocks interact? What's the relationship between these clocks and the clock in the transport? Based on what I see in the YM3433 data sheet, I believe that the following is the case: - The clock in the transport is highly stable. Things are good up to the point at which it feeds the S/PDIF encoder. At this point, the clock signal loses its independent existence, and is passed to the downstream DAC-box via the edge timings in the encoded S/PDIF data signal. - The CS8412 uses its PLL circuitry to recover the embedded clock from the incoming S/PDIF signal. It outputs this clock signal (with whatever jitter was not filtered out by the PLL) to the YM3433, feeding its SCK clock output to the YM3433's BCI (bit clock in). - The YM3433 uses the incoming BCI signal from the CS8412 to clock in the incoming data. - The YM33 takes a separate crystal-oscillator clock, which is used to run the math engine in the digital filter. This clock is not synchronized to the BCI. It just has to run fast enough to allow the digital filter multiply/accumulate logic to complete the calculations needed to generate each output sample quickly enough... if the MAC core is done sooner than necessary, it's put into an idle state to kill time until the previous output sample has been emitted. - The YM3433 also generates BCO (bit-clock out), WCO (word clock out), and two deglitcher outputs, which are used to control the DACs... specifically, the moment at which each DAC chip grabs the new sample that has been clocked in via BCO, and starts converting it to analog. These clocks are generated from the crystal-oscillator input, not from BCI. So... it looks to me as if short-term jitter from the S/PDIF will be partially filtered out by the CS8412's PLL, and then almost entirely eliminated from consideration by the fact that the YM3433 is generating "new" bit-clock and word-block signals from its crystal oscillator clock. However, this approach would not seem to be entirely immune to timing problems... it doesn't guarantee absolute timing stability. The YM3433 still has to track the incoming data rate to some extent... it must adjust its WCO timing to match the long-term rate of the incoming samples. The WCO timing isn't strictly synchronized to either the BCI (incoming bit clock) or to the crystal oscillator, but its falling edge always occurs "during the period between BCO pulses"... which means that its timing is quantized to some extent rather than being smoothly variable. This quantization of the WCO timing will, necessarily, introduce some short-term jitter as WCO tries to track the recovered transport-clock signal's long-term drift. Without examining the jitter spectrum of the WCO line, and comparing it to the spectra of the CS8412's output clock and to the crystal oscillator, it's not possible to say just how well the YM3433 actually performs in this regard. I'd guess that it's probably doing better than a system which used the "raw" CS8412 clock, but not as well as one which fed the DACs directly from a crystal oscillator and then slaved the transport to this same oscillator... but that's just a guess. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
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Posted to rec.audio.tech
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CD player quality recommendation
"Dave Platt" wrote in message ... I am confused as to how all these various clocks interact. For example in my external DAC I've got a receiver chip (CS8412) which has its' own master clock pin (MCK), a voltage-controlled oscillator which is part of the PLL. This clock can be an input or output externally. The only outputs from my receiver are the serial clock (SCK), word clock (FSYNC) and serial data (SDATA). These go into an 8x oversampling digital filter (YM3433) which ALSO has a clock (in fact an external 10MHz crystal oscillator). Outputs are then DATA-R, DATA-L, word clock out (WCO) and bit clock out (BCO) which are fed, respectively, to two DACs (AD1860's). How do the digital receiver and digital filter clocks interact? What's the relationship between these clocks and the clock in the transport? Based on what I see in the YM3433 data sheet, I believe that the following is the case: - The clock in the transport is highly stable. Things are good up to the point at which it feeds the S/PDIF encoder. At this point, the clock signal loses its independent existence, and is passed to the downstream DAC-box via the edge timings in the encoded S/PDIF data signal. - The CS8412 uses its PLL circuitry to recover the embedded clock from the incoming S/PDIF signal. It outputs this clock signal (with whatever jitter was not filtered out by the PLL) to the YM3433, feeding its SCK clock output to the YM3433's BCI (bit clock in). - The YM3433 uses the incoming BCI signal from the CS8412 to clock in the incoming data. - The YM33 takes a separate crystal-oscillator clock, which is used to run the math engine in the digital filter. This clock is not synchronized to the BCI. It just has to run fast enough to allow the digital filter multiply/accumulate logic to complete the calculations needed to generate each output sample quickly enough... if the MAC core is done sooner than necessary, it's put into an idle state to kill time until the previous output sample has been emitted. - The YM3433 also generates BCO (bit-clock out), WCO (word clock out), and two deglitcher outputs, which are used to control the DACs... specifically, the moment at which each DAC chip grabs the new sample that has been clocked in via BCO, and starts converting it to analog. These clocks are generated from the crystal-oscillator input, not from BCI. So the YM3433's crystal oscillator times the digital filter and (indirectly) the DACs. The raw clock in the CS8412 is not used for anything. So... it looks to me as if short-term jitter from the S/PDIF will be partially filtered out by the CS8412's PLL, and then almost entirely eliminated from consideration by the fact that the YM3433 is generating "new" bit-clock and word-block signals from its crystal oscillator clock. However, this approach would not seem to be entirely immune to timing problems... it doesn't guarantee absolute timing stability. The YM3433 still has to track the incoming data rate to some extent... it must adjust its WCO timing to match the long-term rate of the incoming samples. The WCO timing isn't strictly synchronized to either the BCI (incoming bit clock) or to the crystal oscillator, but its falling edge always occurs "during the period between BCO pulses"... which means that its timing is quantized to some extent rather than being smoothly variable. This quantization of the WCO timing will, necessarily, introduce some short-term jitter as WCO tries to track the recovered transport-clock signal's long-term drift. If there is a highly stable clock in the transport, and that clock is used to S/PDIF-encode the signal, how/why would the incoming digital signal to the CS8412 (and, since the timing is unaffected by this device, the YM3433) vary in frequency, i.e. drift? Also, if the YM3433's oscillator were fast enough to perform the logic in realtime with cycles left over, why couldn't WCO rate be adjusted in the same "real" timeframe as opposed to the "long-term rate of incoming samples" you mention, above? Or would this just be passing along the jitter to the DACs? Without examining the jitter spectrum of the WCO line, and comparing it to the spectra of the CS8412's output clock and to the crystal oscillator, it's not possible to say just how well the YM3433 actually performs in this regard. I'd guess that it's probably doing better than a system which used the "raw" CS8412 clock, but not as well as one which fed the DACs directly from a crystal oscillator and then slaved the transport to this same oscillator... but that's just a guess. -- Interestingly, I note that by varying the select pins on the CS8412, this device will accept input in I2S format, no doubt for use within cd players where no S/PDIF encoding/decoding is required. Again, I ask myself "who came up with this S/PDIF format" when I2S is a) built in to every cd transport/player and b) inherently more accurate/stable. I would gladly pay for the extra conductors required to carry the transport clock signal. Ah, but it is a tad more time-consuming to get that DIN connector oriented properly, especially in a dark room... Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
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Posted to rec.audio.tech
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CD player quality recommendation
In article FJOef.113673$S4.19842@edtnps84,
Dave wrote: So the YM3433's crystal oscillator times the digital filter and (indirectly) the DACs. The raw clock in the CS8412 is not used for anything. That's how I see the situation. If there is a highly stable clock in the transport, and that clock is used to S/PDIF-encode the signal, how/why would the incoming digital signal to the CS8412 (and, since the timing is unaffected by this device, the YM3433) vary in frequency, i.e. drift? No crystal oscillator is perfect, and S/PDIF is definitely not perfect. The transport's oscillator will suffer from some amount of absolute error, and some amount of thermally-induced drift. Typical off-the-shelf canned oscillators seem to be specified to have accuracies and stabilities on the order of 50 - 100 parts per million. Warm up the can a few degrees, and it'll drift. There's essentially no chance at all that the transport and DAC xoscillators will have the same absolute error and precisely the same amount of drift. You're always going to be left with a synchronization problem of some sort, in any multi-oscillator system. If the oscillator drifts as much as 10 parts per million during use, then that's equivalent to 1 sample per 100,000 change in timing. The DAC must be able to compensate for this in some way, or it'll occasionally get ahead of or behind the transport by 1 sample. Trust me, in many signals, a single duplicated or discarded sample is audible (it makes a slight but detectable "tick" in the music). The DAC using a 1:1 converter, or an N:1 oversampling digital filter, has to adjust its conversion rate in real time in order to keep this from happening. DAC systems using asynchronous sample rate converters deal with the problem on a more gradual and continuous basis. Also, if the YM3433's oscillator were fast enough to perform the logic in realtime with cycles left over, why couldn't WCO rate be adjusted in the same "real" timeframe as opposed to the "long-term rate of incoming samples" you mention, above? Or would this just be passing along the jitter to the DACs? Bingo. Yes, it would be passing along the jitter. Interestingly, I note that by varying the select pins on the CS8412, this device will accept input in I2S format, no doubt for use within cd players where no S/PDIF encoding/decoding is required. Again, I ask myself "who came up with this S/PDIF format" when I2S is a) built in to every cd transport/player and b) inherently more accurate/stable. I would gladly pay for the extra conductors required to carry the transport clock signal. Ah, but it is a tad more time-consuming to get that DIN connector oriented properly, especially in a dark room... My recollection is that I2S came along somewhat later than S/PDIF - first-generation chip sets used a variety of proprietary, nonstandardized clock-and-data busses. S/PDIF has the advantage of simplicity, and compatibility with the wide range of 75-ohm coax cables and connectors available. It can also be used over a single optical fiber using inexpensive LED drivers and phototransistor receivers. As is often the case, cheap-and-convenient won out over technically- better in the mass market. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
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Posted to rec.audio.tech
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CD player quality recommendation
""Schöön" Martin" wrote in
message "Arny Krueger" writes: snip I find that there still be be significant differences in sound quality due to things like ability to track difficult media. One leading common source of difficult media is home-burned CDs. The degree to which light mistracking can be confused with problems in the analog domain may surprise many. Hmm, the only CDs I have serious problems with are CDs I have bought. Burn enough CDs on enough different types of media and play them in enough different players and sooner or later... ;-) My home-brewn LP-CD 'products' have never caused me any problems. The so-called law of averages comes into play. I was trying to figure out how many CDs I've burned over the years, and its up past 1,000 probably past 2,000 and maybe even 5,000. 50-and 100 disc spindles and packs have been known to "disappear" in numbers within a day or two. I am actually considering clone one of my problems CD to be able to listen to the last tracks on my stereo. This can work - I've played this *trick* a number of times with good success. The key to sucess here is that the better ripping packages (CDEX, EAC) can read and reread a disc until they find consistent results. CD players as a rule do everything on the fly - once and only once. |
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Posted to rec.audio.tech
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CD player quality recommendation
"Arny Krueger" writes:
""Schöön" Martin" wrote in I am actually considering clone one of my problems CD to be able to listen to the last tracks on my stereo. This can work - I've played this *trick* a number of times with good success. The key to sucess here is that the better ripping packages (CDEX, EAC) can read and reread a disc until they find consistent results. CD players as a rule do everything on the fly - once and only once. Well, I think my CD-player is part of the problem because these CDs play without any problems in my computer and other CD-players. -- ================================================== ====================== Martin Schöön "Problems worthy of attack prove their worth by hitting back" Piet Hein ================================================== ====================== |
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