Pink Floyd "Dark Side Of The Moon" UDI/UDII Comparison Results

You all did a great job of verifying that the data itself was not the culprit, but you really didn't get into all the other variables:

hard drives have differing amounts of jitter

DATs have differing jitter, cheap DAT decks sound just like that, cheap.

cd's burned only once using Toast on a Mac can invert the abolute polarity of a recording, in some cases - burning a 2nd cd from the 1st dub reverses the polarity back to the original (presumably commercial) release

Differing brands and colors of cd-r's sound different. My faves to date are the Memorex black playing surface / gold label 700mb disks.

Inking the perimeter or stabilising the disk during playback changes the sound (are those UD-II's cut off center, even a fraction of a millimeter?).

A $20 cheap portable that has a 45 sec buffer (which reclocks the data in the course of buffering it) running on DC batteries can sound better than your $300 rack system cd player using AC power.

- - -

In other words, all variables are of note and may have a sonic effect. Getting the data off your cd's to the D/A converter is in fact an analog process.

btw, any disc I plan to play frequently gets cd-r'd to a dark blue or black blank because they seem to sound better than the store bought originals in 90% of the cases.

This not-glass-mastered disc (cd-r) may be why vinyl run off on cd sounds so amazing. The labels should give up on glass mastering (laughing)!

 

thomoz,

Thanks, but some of those expressed opinions are speculation at best IMHO

What we are dealing with here is a fact in that the UD1's & UD2's, not CD-R's, sound differently. It has been observed and noted by a lot more people than just my self, so insanity is out of the question. As to why, and I can assure you it's not jitter, we are still on the search. Hopefully one day someone will have a reasonable explanation as to why a computer reads 2 different CD's the same when the human ear and brain say they are different, until then...

 

You cannot assure me of that Dave.

If the data is identical, but the sound is different, then the reason must be time-based. Ergo, jitter.

Regards,
Geoff

 

I also read that the Blue Dyed CD-R's had an effect. In an Audiophile magazine there was a test of CD-R's to try and find out if there was a difference. There was, and the Blue Dyed CD's (TDK's in this case) sounded better than the originals, ever so slightly. I guess it's what one's interpretation of 'better' is.

 

Are you talking about the jitter in the recordings them selves or are you talking about the CDP jitter?

 

Reading that Bob Katz jitter article for the first time, you'd almost think that it's a new problem exclusive to digital audio. But actually, not only is it much more prevalent in analog devices, but it can be thousands of times more audible, in the way of wow and flutter.

Analog jitter, being low band, is far more in the ears' audible range, while digital jitter is well above the sampling frequency. So why has it suddenly become such a big concern and catch phrase - other than to sell more equipment? It's like arguing about a grain of sand, when we lived quite comfortably with it packed in our pre-digital shorts for years. I'd worry about the linearity of my system well before ever becoming concerned over jitter.

Currently, it is possible to build a cheap DAC that can still isolate jitter to an imperceptible amount, above 80 dB. So, if time-based jitter is the main problem in your system, then you indeed need a new one. Because either your transport is improperly tracking cds and dropping uncorrected bits, or it's an early single-bit DAC with a poor clock, or it's not properly grounded.

Therefore, two identical discs, read in a bit-perfect manner - with proper error correction - and played back on the same system are going to be audibly identical.

Josh

 

Don't you mean should sound the same?

This is the whole case in question as 2 identical bit for bit disc's don't in fact sound the same. Great theory though.

 

Not only would they sound the same, but they'd be audibly identical. And they'd also be as redundant as that sentence.

Actually, I tried the null test several years ago on my UD1 and UD2 and found no difference. So I can't really explain the differences that some people are actually hearing.

But the null test is pretty much the most accurate test. And if two bit-identical discs are played back with one system being the control, barring some cataclysmic event, they would indeed sound the same.

Josh

 

Apparently not as accurate as the human ear, but you are entitled to believe what you like.

 

I guess I'd say *more* accurate than most CD players...

At least we can finally toss out all the "MoFi tweaked things for the UDII's" arguments.

 

Yes, I can agree with that part Luke. One down, one to go. I still can't get over how come my CD number is sooooo different than anyone elses. More mysteries.

 

Thank goodness. You guys were hurting my wallet bidding for those elusive UDI releases on eBay. I'll just listen my my UDII's with a smile from now on

 

Sorry to kick your wallet where it hurts Sam but....the UD1's are still better. Although, if you like a slightly veiled sound....The differences are not huge, with the exception of this particular one, but they are still there.

BTW did I ever mention that it was Gary who got this all started with me and knew this through listening through his MacIntosh system? He told me about the difference so I asked him to bring his UD2 DSOTM and dag-nab-it I've never been the same since.

 

The thing is, Dave, I really think it depends on your playback system. Some players might not have the problems with UDIIs that yours does - obviously those with a CD-ROM type mechanism won't produce *any* differences. Plus, those that *do* have issues might find that simply burning a CD-R will clear things right up. I'd say your money would probably be better spent getting UDII copies of everything and a Yamaha AMQ burner, instead of hunting down UD copies for more money.

 

I dunno Dave. As we've discussed in the past, I was not able to notice obvious differences. Since we've determined the copies to be identical from a bit standpoint, any differences I came across may have had more to do with where I sat my butt on the couch in relation to where I sat for the previous disc

Until someone can show me disc differences from an analytical standpoint, I guess I'm gonna have to "agree to disagree" with you on this one.

 

I would tend to agree that it is playback system orientated. On my system I get the same results even with them being CD-R'ed, my CDP is 3-4 years old and not a cheapie. Fortunately for me, I went for the UD1's along time ago and only want one more, BTW speaking of such....Do you know if the MFSL Elvis is any good?

Gary, if you're still reading....Are the differences still there after all of your recent up-grading?

 

For the life of me, I have not found this to be the case.

Although I've only burned a few dark blue CD-R's (and many more silver ones, actually), when they've been direct copies, my system - old as it is - plays them back no differently than the original CD. I also hear no difference playing through the computer soundcard listening w/ headphones - at work or at home (two different computers and soundcards). Yet vinyl recorded to my computer (and later burned to the CD-R) still does sound better to me than an original audio CD of the same thing - in most cases so far. I have only been at this for about a year now.

This, at least, has been my experience.

Besides, this whole thing was about perceived differences in the original manufactured glass-mastered MoFi discs - not CD-R copies of those discs. Even though it was CD-R copies that were used for direct bit-for-bit comparisons. I assume they were both ripped on the same system, burned on the same system, and sent to a different system to then have both compared on that same system.

I tend to lean to the idea of the "power of suggestion" after following this thread.

Joel

 

Wait. Are you saying you can *still* hear the differences between the UD and UDII when you burn CD-Rs of both of them? If so, something is *seriously* wrong with your CD-R setup. Regardless of how the originals sound, if you copy 2 CDs to your hard drive and they turn out to be identical (as these have), there's NO reason why they should sound different after they've been burned. I mean, it's no different than burning a CD twice and saying the second burn sounds different from the first.

 

Still, the retail and the CDR copy came up identiacl bit to bit. That being the case I would also argue that the percieved differences would have to be with the listener.

 

This ought to be easy enough to verify. Someone with both versions should rip them to HD, confirm they're the same, then make twenty CD-Rs (some random number of UD and UDIIs -- not ten of each). Label them in a way that doesn't give away which is which. Then send them to Dave (or someone else who hears a difference). The listener then identifies each disc as a UD or UDII. If he gets them all right (or does significantly better than random chance), then there's something weird going on.

(Would timing differences unrelated to sound quality give them away, though?)

I can understand if no one's interested, since that's a lot of listening to one record, but it might be a fun experiment.

(I've never even heard the UDII, so don't send me any discs! )

Ryan

 

If anybody would like to compare their different versions of these discs, we should, in theory, be able to do so using EAC. If we do this right, we should be able to determine if there are multiple versions of the UDI discs, for example, without mailing our discs to each other.

If you have EAC set up correctly for your drive(s), including offset information, simply generate a CRC for a certain track (or tracks), and post it here for comparison.

My original UDI of DSotM generates a CRC of E6425622 for the track 'Money'. And I do trust this checksum, because I get this same checksum on both of my extraction drives (both carefully set up for all EAC options, including offset).

I would trust this less with CD-R copies, because that requires the additional assumption that the copy was made perfectly.

And if you don't have at least two drives for extraction, and they are generating the same checksum, you probably don't have your drives set up correctly (or they are inaccurate).

If everything is set up correctly, CRC data should be as meaningful as inverting and summing. The odds of different data of this size generating the same checksums would be comparable to winning the lottery.

Obviously, no scratched discs need apply.

 

Yeah, except then we'd be trying to prove that cd-roms/cd-rs are imperfect, and not simply that the two Mobile Fidelity releases are bit-identical.

The human ear may indeed be pretty accurate, but I've yet to see one interpret information in the digital domain. By extracting a bit-perfect copy, the data never goes inside the analog domain while being examined - so it isn't susceptible to playback jitter. In other words, it's really my eyes that are seeing that indeed the two, UDI and UDII, were identical to the last bit.

By the way, I can also listen to the wave file on my computer, without/without a null test, and also hear that they are identical. In fact, to qualify the test, my sound card measures better than most transports and stand alone DACs - that includes jitter distortion. And the earcanal phones used to measure any differences are considered the flattest, most accurate, monitors in the world, the Etymotic ER-4S. It's like placing a microscope over the music; I can hear if even a stray nose hair is audibly out of place. So upon playback in the analog domain, the null test is conclusive enough evidence for me.

 

You can hear it or the computer is showing you the difference? I can hear there is a difference, computer or no computer.

 

I tend to agree with my fellow Baton Rougian.

 

Me too Also from the deep south.....

Chris