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

DSOTM: UDI/UDII Comparison Results

Thanks to forum member SamS, I received CD-R copies of both the UD and UDII versions of MoFi's Dark Side Of The Moon in the mail today. As has been mentioned several times, some members prefer the sound of the UD over the UDII. As comparisons of other MoFi titles showed the UD and UDII versions were digital clones, I wanted to find out what the story was behind Dark Side. It's commonly believed that MoFi did some type of "remastering" for the UDII. Well, after doing a comparison, the results are in (drum roll please)...:

The two versions are digitally identical.

Yes, that's right, the same. How, may you ask, did I come to this conclusion? Simple. I extracted Eclipse from both CDs onto my hard drive. I then loaded both files up in ProTools, and lined them up as to be in perfect sync. I then inverted one of the files. [This is known as a null test, and is a key technique to determine if two digital files are the same or not.] The result? Total silence.

Just to make sure there wasn't something there that I wasn't hearing, I made a mix of the two files, and opened that up. A peak level scan didn't even register - that is, the resultant mix was nothing but pure silence.

Now, apparently some people *can* hear differences between the two. *Why* is an interesting question, but one that can't be answered at this time. It is most likely the same reason that people can hear differences between different CD burners. Jitter? Something else?

But, at any rate, the two discs indeed have identical musical data.

 

Interesting results Lukpac.

When you listened to the two discs did they sound identical to you?

 

Well, as I mentioned, these were CD-R copies, so any "differences" in pressings would have been evened out. Thusly, yes, they sounded the same.

 

Wouldn't any differences between the two pressings also show up on a recording provided the same recorder was used for both? I would think even if the sound were changed by the recorder, it would change both in the same way still leaving a difference if one existed. I dunno...I'm far from an expert on this stuff.

 

Ok... just to throw something random into the ring...

Is there any chance that the UDI used preemphasis, and when they cloned it for the UDII they forgot to set the bit?

That would explain how they could be indentical bit copies, but *sound* different -- when playing the original discs, of course. It would also explain why Luke doesn't hear any difference - if the preemphasis bit was lost completely on the UDI when the copy was made for him.

Any of that make sense?

Jeff

 

Luke - is there a way to check if the pre-emphasis bit in any software under mac os x?

I have a UDI DSOTM - I could check if I could find the right software.

jeff

 

HOly Smokes! What a shocker. As for HZ's theory......I need to think about it a bit more before it make sense or I can offer a comment.

Gary,

I don't feel that CDR's can sound different. I just did a straight digital copy of each. I reported on this earlier. Remember, I said the data on the discs are different, but only related to tracking times, etc. As I found out with "Honky Chateau", once the tracks are properly synced, the are bit-for-bit identical.

Thanks for your efforts, Luke.

 

Just in case anyone thinks Luke and I are in cahoots over this whole thing......Luke can surely verify the discs are different as related to track syncing and such. Some of the markers are different on a digital level. Luke, wanna confirm this so people realize I really did send you a copy of a UD1 and UDII?

 

Sam - do you hear a striking difference between the two? Or is it a more subtle difference? (or no difference)

 

Don't know about OSX, but Astarte CD-Copy works under OS 8/9, and will tell you if a track has PE or not.

FWIW, I tend to *not* think this is the case, for two reasons:

1) I don't think PE was still used much by the time MoFi did DSOTM.

2) These CD-Rs sound very close to my Capitol CD. I'd think if there was a PE issue they'd be a *lot* brighter. They aren't.

 

Luke - do you know if I suck my UDI in with iTunes, --if-- it had PE would it lose it?

If so, I could burn it, and then compare my original with the burned copy from iTunes.

Regardless, you're probably right about PE not being used.

jeff

 

No. If there was something "flawed" about CD-Rs, you wouldn't be able rip an original CD *and* a 10th generation CD-R copy and have them turn out the same.

I've done some tinkering, and even the *slightest* change in EQ/volume/etc will *clearly* manifest itself in a null test. That is, you'll hear music, not silence.

And, yes, as Sam has pointed out, the indexing on the two copies is different. I had to slide the tracks around to get them to line up exactly.

 

My guess is iTunes would ignore the PE, and your burn (and MP3s) would come out brighter. *Significantly* brighter.

You can give it a shot, but like I say, I tend to think that would be a *huge* longshot.

Shoot me off an e-mail.

 

I have the UD1 DSOTM.

Just loaded it up in EAC.

No pre-emphasis used on this disc.

Should rule that out.

Joel

 

To give everyone a better idea about how *any* processing will show up in a null test, I just did an experiment. In a small section of the area I performed the null test on, I adjusted the volume on the non-inverted track by -.1 dB. The previous silence changed into a very quiet version of the music. Next, I took that same section and adjusted the volume by +.1 dB. While the music was gone, a small amount of white noise (at around -73 dB) was left behind; while the two versions were *very* close, they were obviously not identical after processing.

What does all of that mean? Well, it means that *any* processing to a digital file will result in a non-null result in a null test. As previously mentioned, the comparison of UD and UDII ended with a *null* result. Thusly, no processing was done for the UDII - it was nothing more than a digital clone of the UD.

 

HZ,

Good question. I was always skeptical about this and had a few PM's with Dave (where are ya?) concerning my (in)ability to distinguish the two. In the end, after much A/B'ing, I "thought" I preferred the UD1. I made reference to it being "less cardboardy-sound". You can ask Dave, I had a hard time arriving at this conclusion. Just goes to show how tough it is to compare two things at the same time and the power of suggestion.

 

It is true what Sam says. How I came to the conclusion was right with Gary in my livingroom when he brought over his UD2 as I have always only had the UD1. All I can say is that there was no way you couldn't hear the rather large difference between the two and according to Gary it had the same differences on his system.

God Sam, I sure wish I could talk you into droppin' by with your UD2 sometime.

 

Hmm... makes me wonder if there was a different "bad" mastering/pressing of the UDII? DSOTM was mofi's most popular release, right? I suppose it's possible that they remastered it somewhere along the line if they found out that they made a mistake in a certain pressing.

 

There could be more than one run of UDIIs and at least one is sub standard. It happens. I had a DCC "Rock of the 70s" Vol three that was flawed.

 

Take mine as a random example in this UD2 DSOTM experiment. I never liked the way it sounded. I have not heard one report yet of UD2 sounding on par with UD1 with this title. So the notion of a bad batch of UD2's doesn't seam likely.

 

I *think* perhaps this is just an issue of Dave's CD player making a fuss over the UDII or something. It wouldn't surprise me if on a different player (one that could read things better), Dave wasn't able to tell the differences between the two.

 

If one makes the assumption that Luke's null test tells absolutely all about the sonics of a disc then there is no difference between UD1 and UD2 DSOTHM.

But don't forget the old adage that "all amplifiers that measure the same sound the same". And we all know that ain't true!

On my system I prefer the sound of the UD1. Results may vary depending on the individual and equipment.