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Can different CD *transports* sound different - when fed into the same DAC?

jonUK

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Apologies if this has already been done, but nothing really discussing this came up when I searched. The question is simple, but I don't have enough technical knowledge of SPDIF etc. to say whether it is even possibly the case, or not. But my thoughts are that it sounds very unlikely anyway and that all CD transports should sound the same, and that if anything is going wrong between the transport and DAC it's more likely to result in dropouts or "digital garbage" noise rather than subtle differences in soundstage or things of that nature.
"
By the way, this is why I'm asking the question. Funnily enough, it came through as a recommended video after I watched one of Amir's videos... This chap (who I don't know, have never seen any of his videos before, so I have no preconceptions about whether he's knowledgeable, or not) claims that doing blind testing (but not he admits, double blind) he was able to reliably pick out the difference between a cheap Blu-Ray player, a middle of the road CD transport, and an expensive player - when played through the same DAC connected through a Coaxial SPDIF connection. He heard a "nicer soundstage" "more detail" etc. on the more expensive items, and described the cheap BR player as sounding "congested".


Thoughts appreciated.
 

solderdude

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Differences in transports will be in:
Ease of use.
TOC read speed.
Skip speed.
Longevity.
Display.
Functionality.
Tactile feel of buttons and disc drawer.
Mechanical sounds emanating from it.
Immunity to external 'vibrations'.
Ability to read scratched discs.
Ability to also read DC-R and even CD-RW or other (DVD/BR) formats.
Differences in connectivity/outputs.
Looks, size, weight, price.

As you can see there is no 'sound' in the list above but there certainly are differences between transports in the areas mentioned above.
They all simply output the bits retrieved from the disc and present that on the digital output, regardless of the type of output.
That part is the 'transport' part.


When you mean player (so analog out) then yes... there can be differences in sound quality. Some very cheap ones can have really crappy DACs inside and some (more expensive) could have some analog filtering that makes them sound different than others. Some may find that 'better' or 'more musical' or whatever they think but in reality it just deviates from the recorded signal (on purpose).
 
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jonUK

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I can appreciate that Solderdude (also whether or not it can read CD-R/RW's might have been a consideration once). If you can churn out a BR Player for $50 or less, the chances are the build quality of it is not going to be up to much.
 

solderdude

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Yep, will add that for the complete picture.

Cheap BR/CD/DVD may not have the best (analog) audio-out.
 

Blumlein 88

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I'm just into the first part of the video. And a guy says they level matched them. Within .23 db.......................nope not good enough. And apparently this is both a DAC vs CD player comparison and a digital transport comparison.

Starting with the transports. So then he describes things like forward midrange, and soundstage and blah, blah, blah. He says on one comparison they switched back and forth a lot, and leaves you thinking the muddled Sony was perhaps only listened to once. Did he identify them different reliably 10 of 10 times or 1 of 1 or did he even keep those kind of notes. It is not clear. Did his test consist of switching everytime knowing he was hearing one of two though not knowing the identities of the two in use? If so, and that is how it seems from his description, then this test isn't worthwhile at all. Generally if you let someone hear A and then B, they'll think they hear differences. If they know when it is A and when it is B they haven't shown they really hear them differently. If it is A sometimes followed by B and sometimes by A and vice versa you can get somewhere, but this doesn't sound like what they did.

Now when you get to the CD player comparisons, it does not sound blinded at all. Just listens and described and surprise, surprise his evaluation follows the price directly.

Now we get to his explanation on the transports and we have 100% crap. The old jitter bugaboo. The power supply on the digital out blah, blah, blah crap. You could listen to my 8th generation copy files. The file is sent thru a DAC with some jitter, into an ADC with some more jitter, rinse and repeat 8 times. Could have like 16 times the jitter in the final file. You will be hard pressed to hear any difference. Plus he just assumes jitter performance follows price. We know from Amir's tests that is not at all true. And error correction, oh please, this virtually never happens, and if it happens the data is corrected anyway. You don't hear that. You cannot hear that. And then he finishes with the old my system is highly, highly resolving and perhaps your is not and you won't hear it. He has young ears too he says. Gag a maggot with a spoon bad.
 

solderdude

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re: error correction.

Most people use the word 'error' correction when they mean tracking & focussing.
Those are different things.

Tracking/focussing/speed control is mechanical and analog in nature. It is not related to audio content.

Error correction is done using various methods.
Audio data is taken apart. Put in 'chunks' and these chunks are padded with extra CRC bits and other info and put in a disc specific format. These chunks are then spread a bit (interleaving).

When reading the disc the stream of data is clocked into a buffer.
The disc speed is governed by the 'fastest' occurring bit change coming in which is compared to an internal clock (PLL).
The incoming data is de-interleaved (put in the right order again).
Then the data is checked (using CRC method) and then, if needed based on math, corrected.
This is not an estimation but mathematical and done using the extra bits. Thanks to the 'interleaving' relatively large 'gaps' in data when making 'reading errors' due to scratches, dirt, fingerprints, poor disc quality (pinholes)/CDR/CDRW lower output, that data loss is spread over various parts so error correction can accurately calculate what the original data was. NO estimates. Only in very severe cases the errors become too severe and remain 'unrecoverable' (CUerrors) which then are handled later on when flagged that way.
Remember, CD reading is NOT realtime.
Decoded, corrected audio bits and extra data is pulled apart.
Audio data is then sent in the internal data format and goes to a digital output or is processed further for its own DAC.

There is nothing 'real time' about playing a disc as there would be in analog reproduction.
 

MattHooper

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I'm just into the first part of the video. And a guy says they level matched them. Within .23 db.......................nope not good enough. And apparently this is both a DAC vs CD player comparison and a digital transport comparison.

Starting with the transports. So then he describes things like forward midrange, and soundstage and blah, blah, blah. He says on one comparison they switched back and forth a lot, and leaves you thinking the muddled Sony was perhaps only listened to once. Did he identify them different reliably 10 of 10 times or 1 of 1 or did he even keep those kind of notes. It is not clear. Did his test consist of switching everytime knowing he was hearing one of two though not knowing the identities of the two in use? If so, and that is how it seems from his description, then this test isn't worthwhile at all. Generally if you let someone hear A and then B, they'll think they hear differences. If they know when it is A and when it is B they haven't shown they really hear them differently. If it is A sometimes followed by B and sometimes by A and vice versa you can get somewhere, but this doesn't sound like what they did.

Now when you get to the CD player comparisons, it does not sound blinded at all. Just listens and described and surprise, surprise his evaluation follows the price directly.

Now we get to his explanation on the transports and we have 100% crap. The old jitter bugaboo. The power supply on the digital out blah, blah, blah crap. You could listen to my 8th generation copy files. The file is sent thru a DAC with some jitter, into an ADC with some more jitter, rinse and repeat 8 times. Could have like 16 times the jitter in the final file. You will be hard pressed to hear any difference. Plus he just assumes jitter performance follows price. We know from Amir's tests that is not at all true. And error correction, oh please, this virtually never happens, and if it happens the data is corrected anyway. You don't hear that. You cannot hear that. And then he finishes with the old my system is highly, highly resolving and perhaps your is not and you won't hear it. He has young ears too he says. Gag a maggot with a spoon bad.

Exactly!

They were going through all the "this is how careful we were" steps and I'm thinking "interesting" and then...he totally skips describing the actual test! Like...how many trials? What type of switching (randomized)? What score did he get and for what precisely? He must moved right on to ascribing differences between the transports.

As you point out, even if you just label something A and B, if you know you are trying to detect differences between A and B you can imagine and describe those differences.

Yeesh. At least it seems there are more people out there attempting blind tests. Hopefully we'll see a good one at some point.

(BTW, I'm not one to really talk that much - I've done blind tests and they can certainly be tough to pull off to get truly confident results. I mean, even in science, studies and placebo-controlled tests are often torn apart by scientific colleagues. But some of these guys are just making basic missteps it seems).
 

hifiman2008

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As a long time employee in the industry. I can guarantee a customer will hear a difference if you tell them there is one. You simply suggested it. " listen to this particularly expensive model"..then 'now listen to a cheaper mass market one". U have already put in their head to expect it to sound worse. U could play the same player twice with that line and a customer would hear a difference.
 

rentaclaus

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When the laser and the optics are uncalibrated and deliver e.g. malformed eyepatterns, its possible. But thats a case for: the player needs to be repaired.
 

MaxwellsEq

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Having been working as an engineer in the earliest days of CD, I was trained to set up CD transports, lasers and optics. Quite a surprising amount were not optimal when out of the box, and many drifted over time. In general though most commercial CD players were able to play good condition CDs OK, even if not optimally configured.

It is quite possible that three different transports are slightly misconfigured and so may make a less than perfect job of a slightly poor disk and they may have poorly designed buffers etc. In order for the test to be valid, all the transports would need to be tested and adjusted. Then they should be measured with test discs to confirm they are counting and/or correcting errors at the same rate. Only then could you argue that it's a fair comparison. Otherwise the test may only be measuring the health of the player not whether there is a fundamental difference.
 

DVDdoug

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Within .23 db.......................nope not good enough.
It's good enough for my tin ears! :D :D :D

There are two reasons for level matching... Louder usually "sounds better". People will say it's 'more dynamic", etc. And if it's a LOT louder, Fletcher-Munson comes into play and it sounds like the bass was turned-up even more, and you can hear details you weren't hearing at the lower level, etc. So it probably DOES sound better!

But the other thing is, if there is a small-detectible difference, the louder one might not "sound better" but in an ABX test the level difference is a dead give-away and you can identify "X" every time and that makes the ABX test (or any blind test) useless (unless you are intentionally listening for level differences).

There can be read errors and error-differences with different players. If you've ripped CDs you've probably had a situation where one CD reader got errors but it worked with another reader or another computer. CD players seem to pretty good at error correction (or "error hiding") but I wouldn't assume they are all equal. I've had CDs that "play fine" on a player, but have audible glitches/errors when ripped.

And I assume it's possible to have speed problems but I've never noticed that. I don't know if it shows-up as a speed-pitch error like a vinyl record, or if you get glitches from the data going-into the DAC at the wrong sample rate. (A sample rate error in a soundcard sounds exactly like a record played at the wrong speed with no other errors... Just the wrong speed and pitch.)

...I've NEVER heard a defect or noticed a difference (with good CDs and working players) even with different players and their different built-in DACs. I also have not done any listening tests or tried to hear a difference. I don't WANT to hear defects! If it sounds good, it sounds good... In the vinyl days the clicks & pops annoyed me but I wasn't trying to listen for them.
 

voodooless

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From the way the “results” are described you just know no prober testing was done. It probably wasn’t even half blind :facepalm:
 

bevok

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If there were issues with reading the disk/errors these would present as very obvious dropouts/distorted garbage though wouldn’t they, not the kind of differences he is talking about?
 

MaxwellsEq

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If there were issues with reading the disk/errors these would present as very obvious dropouts/distorted garbage though wouldn’t they, not the kind of differences he is talking about?
There are levels of error. Things have gone quite wrong if you get dropouts or garbage.

There are a lot of tiny errors which are fixed perfectly, due to checksum and the cutting up of data and distributing it around the disc. A badly configured reader will have more small errors and be working harder fixing these small errors than a well configured reader. As anyone who has used EAC or similar to rip a disc that's errored, it's possible to get it to read the section over and over again and sometimes it can fully correct a disc that would otherwise cause audible or inaudible error in playback. If you are playing the disc in realtime, the bits are written into a buffer, but the player doesn't have time to have another go at reading the faulty section.
 

Talisman

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My personal experience.
from any cd/dvd player, if the data stream is stable, once the digital audio is out and sent to the dac, you won't be able to hear any difference.
The only difference you can hear is so striking that it is not in the quality of the music but in its ability to reproduce it.
Nothing like "depth" "refinement" "detail retrieval" "bass accuracy". It wouldn't make any sense.
 

drewdawg999

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I just switched CD players as transports, from an Eastsound CD-E5 to a Sony CA70ES, fed via optical to a SMSL DO100. The Sony changer reads discs much quicker and has CD text, reads burned discs much better as well. The sound quality I'm getting is spectacular, mostly due to the DAC with XLR balanced out. I think the Sony sounds better despite being much cheaper. More sparkle and shimmer in the highs, more definition overall with a brilliant defined bass. Could be placebo but hey, doesn't matter as I'm enjoying the CDs so much it's put my formidable and beloved analogue rig to shame. Just load the thing up and go 5 hours plus without having to move. Even got the remote working, although it's quite beat up after surviving a dog chewing, still works and essential for my lazy ass.
 

JoachimStrobel

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I have a Parasound DAC 2000 D/A that I tried feeding with 3 CD Streams:
Parasound CD Transport via XLR
Oppo103 via Coax
Panasonic Laserdisk player via Toslink.

I had two Cd which I accidentally bought twice.
The XLR and Coax stream sounded identical, the Toslink was not as good. If that reflects the transport I do not know. I tried for years to buy a CEC/ Parasound belt drive CD transport just for the fun of it. However, the fun was too expensive and now I stream and CDs are a thing of the past.
 

benkatz

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Yes they will. I don't know why whatsoever, but they just do.

I've got the following system:

Triangle Genese Quartet speakers,
Yamaha A-S2100 int amp
Cambridge Audio CXN v2 DAC/Streamer
Cambridge Audio CXC CD transport

I tried 3 different CD transports:
CXC - sounds fuller both down low and up top and wider. (Coax connection)
Yamaha CD-S700 - similar to CXC but male voices were thinner - clear difference were on The Verve's songs (coax connection)
Sony 800x blu ray player - very noticeably less wide and thinner overall sound with tinny highs (optical connection).

I do realize there are many people who have done and shown different measurements and how there shouldnt be a difference in sound. And i believe these measurements were done correctly. However the reality is that I've done the aforementioned comparison and there was a clear difference with a clear advantage to the CXC. I wanted to keep the Yamaha as I could use the single remote (my amp is also yamaha), but the difference was there, and I sold it.

To reiterate if its not clear: The Yamaha is a cd player (internal dac) but in all cases I used it as a cd transport, digitally connected to the dac streamer.
 
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