DCC Archive EAC and exact digital copies

Since some people here are familiar and proficient with the process of making digital copies with EAC and CDRWin, I thought I'd ask this here.

I'm curious as to how to confirm that the copy made using these programs is exactly the same as the original. I have EAC set up correctly for my burner, and I made a disc image and CUE sheet, taking note of the CRC at the end of the process. I then burned this image to CDR using CDRWin.

Reversing this process, I burned a disc image and CUE from my CDR copy to get the resulting CRC for comparison. This was different from my original. I also checked a song from the original and the copy, which again resulted in different CRCs.

I was under the impression that the CRC should match if the copy is exact. Is this right? Is there another way to compare the original and copy to verify they are exactly the same?

Thanks in advance for any pointers.

 

This is an interesting area of inquiry, and one that I would like to understand better myself. I don't have a burner myself, but have been evaluating the market for computer burners for a while. There are burning software programs that claim to be able to make exact copies of audio CDs or CD-ROMS. EAC is one such program. CloneCD is another, although I have heard that it is more likely to have problems with audio CDs that some other programs.

The related issue that has had me intrigued with regard to copying CDs is that of jitter - I read the article that was referred to on this board recently (http://www.digido.com/jitteressay.html), and i must say I haven't yet got my head around the concepts involved. But it does appear that a true exact copy of a CD is an almost impossible task. I found this surprising, as I thought that exact duplicates of CD-ROMs were critical if data integrity was to be maintained, or if copies software was to work. Audio CDs can tolerate a certain degree of error through error correction on playback.

The other interesting thing that seems to emerge from the jitter discussion is that audio CDs made on a computer burner may be better in terms of jitter than those made on a standalone burner (at least for duping of CDs, not for LP to CD burns). I'd like to hear opinions as to whether that is true. Of course, the differences may not even be audible. There appears to be the view that transferring the digital audio signal to a computer hard drive somehow eliminates jitter, or doesn't add to it, because of the way the data is transferred. I really don't understand it fully. I wish someone could explain this stuff better for the benefit of us all.

 

If you extract your CD via Burst, that's just fine, but if you want to make every bit and but absolutely letter perfect to the disc (for anal nutballs only) run tests to make sure that your CD ROM or CDR Drive supports Secure Mode (Detect Read Features for this folks, don't just ck them off)

Hope this helps. Remember, if your stuff will only do burst mode only, don't fret.

 

I disagree with jitter being reduced on computers compared to stand alone burners! The entire process of copying onto a hard drive brings up a host of issues. I have found that often, a hard drive cannot keep up properly, often resulting in audible distortion. This varies with every brand/size/speed of hard drive. Buffers seem to help. Even still, computers are more concerned with bite accuracy than byte timeing. Haveing compared several hard drive setups and my stand alone audio burner, the audio burner always wins.
The other factor is read and burn speeds. Even stand alone burners will suffer jitter when burning at higher than 1X. Timeing gets even more critical, and suffers it seems. You may wish to read Fremers article in Sterophile about burn speeds with the JVC audio burner.
What to look for ( I mean listen!) are sound stageing will colapse, highs get more brittle, and textures will change. Often violins will sound more steely, dynamics suffer (no compression, just attck and decay seem different).
In the early days of CD's and burners, often people noted that CD copies from the Pioneer PDR-1 were beter than the originals, and jitter is often cited. It seems that if one makes a good copy, with a stand alone audio recorder, good cables, and good source (remeber it required another transport to play the original, connected with an RCA to the burner), the copy sounded better. Still seems to hold true to me.
On the other hand, CD-R's for the computer are cheaper, and for the car, they sound ok to me!

 

My CDR drive does support secure mode via 'accurate stream', and I have it set it up as so. There is an excellent EAC tutorial at the following website for setting the myriad of options in EAC:
http://www.ping.be/satcp/eac00.htm

So with EAC set in secure mode, and with no errors on the rip, I'm getting an exact copy despite the difference in CRCs?

 

I've never had problems with CloneCD...as long as you don't do anything processor-intensive, you should be fine. Better yet, the fact that it does RAW reading means that you get perfect copies more often than not.

Jitter is largely a bygone problem...some drives are better with it than others, but there're excellent ways to compensate for it.

Also, you're right...it's hard to make an "exact copy of a CD." But you're thinking of it in the wrong way (i.e., the way you'd THINK that implies). Essentially, while it's difficult to impossible to exactly copy a CD, it is EASY to make a CD with the exact same stuff on it.

Confused?

Here's what that means. Say you have CD A, made at some pressing plant. CD A has a table of contents, certain information in certain cases, et cetera.

NOw say you copy it with Clone CD (disc image, then CD). Now, due to the way burners work, and the way TOCs work, et cetera, the data is not necessarily going to be in the same place...something that occupied a certain sector might be in another sector. But it doesn't matter, because all of the data's there, and in the right order...it's just not EXACTLY in the same place. Additionally, TOCs vary, lead-outs vary, et cetera.


Thus, say you copy an audio CD using Exact Audio Copy. Well, EAC doesn't do RAW at all...it copies tracks to WAVs. These WAVs, do to the incredibly anal way EAC does things, will almost ALWAYS be the exact same thing that was on the CD (minus perhaps a few sectors at the beginning or end due to CD drive peculiarities, et cetera, but that's not really a "problem" per-se...it's why when you ripa track twice, you're likely to get SLIGHTLY different file sizes). If you have good eqiuptment, though, burst can often be quite teh same. Anyway, say you do this, then re-burn the WAVs onto CD with your burner. The CD you've just burnt is, from a "clone" standpoint, nothing like the one you've copied, yet its content is teh same. RAW mode burning tends to be closer, but exactness is a non-issue.


Get me?;-)

-D

 

Exactly. Besides, a compact disc isn't a master tape. Just do what works for you, and have fun.

 

Sorry, that's just silly. Most hard drives are much faster than CD-ROM drives. Besides, if the hard drive can't keep up, the CD-ROM (or CD-RW, if you use that for ripping) will wait until the hard drive can catch up. That's just how those things work. It will *not* simply keep reading even if the hard drive can't write.

While there *might* be *some* differences in very low level data, it's not enough to cause differences in sound. Just ask certain well respected mastering engineers...

 

According to the "stereophile" site, a reader had noticed that the polarity of all the CDs he'd burned on his computer was the reverse of the originals. He used Mac, the Toast software and an APS burner. He claims to have heard the same effect from other CD burners and a variety of platforms. "My fix is to make a second-generation copy, and that simply corrects the polarity by reversing it again. It does make a difference."
Maybe this is something that is specific to Toast or to that reader's burner?

 

All very interesting - thanks David for explaining some of those ideas. I'm still not 100% clear on what jitter is about, but like you say, you've just gotta see what works for yourself, and let the ears decide.

The jitter FAQ does suggest that jitter will be minimised by slow burning speeds.

I do remember when CD-R first hit the market (like, well over 5 years ago), and a British Hifi magazine was claiming that CD-R copies sounded better than the factory-pressed original (can't remember which burner). I've almost got my head around that one, but if someone could explain how that works in simple English, I'd be very grateful.

BTW, I've also heard that Feurio is a good software program for burning audio. Any opinions/experience with that one?

 

Feurio works on the same principles as CDRwin, and unless you specifically have a preference to program layout and interface, they're really like apples and apples. If one tastes sweeter for you, then good.

I stand by my EAC and CDRwin and on a Atapi-layer hacked Windows XP, CDRwin and EAC work in predictible, easy and harmonius results.

Experiment with a few, but I would only recommend one try 2-3 burning packages at a time, and then STAY with one that suits you. Unless I'm making a VCD, CDRWin and EAC are all I'll ever use for most anything, including data Cds, bootable or not.

 

I'll take a stab at this.

The reason that some claim CDRs sound better than the original CDs could (and, BTW, I find this to be ********, so this is strictly devil's advocate stuff) have tons of pinhole problems; naturally, the audio's already been interpolated by the point it gets onto CDRs, and the CDRs don't *have* those problems. Thus, less on-the-fly error correction goes into CDRs.


Some drives are also notorious for reading certain CDRs better than regular CDs (playstations, for example, love darker colored CDRs).

But altogether, I think it's largely ********, really.

-D

 

It's mostly ********. CDRs are, in large, read easier than most aluminum CDs, so you have a more accurate bitstream going to the DAC. Also true, most CD Rom drives (Even DVD-Roms, CDR Cdrives) read better than most regular CD players.

However, garbage in, garbage out. You can't take a sad song on CD and make it better from merely copying it.

 

Here are two more good jitter links:

From Jon Risch

From Gabe Wiener

 

Thanks for the illuminating info. Hey Sckott, what do you mean by your system being "ATAPI-layer hacked"? How is Windows XP handling burning?

In another thread, I mentioned a new Yamaha burner that I'd read about. I guess it's relevant here, with regard to the jitter discussion. Their new model CRW3200E seems to be targeted at audiophile types - it has a feature called "Audio Master Quality", which aims to enhance the playback quality of recorded CDRs by reducing jitter. It does this by altering the rotational speed during a burn, and hence lengthening the pits burnt - this in turn makes it easier for players to track. I hadn't realised that the red-book specs allowed for such a variation in speed.

Here's a link: http://www4.tomshardware.com/storage/01q4/011213/cdrw-14.html

This reviewer states that the difference is noticeable upon playback. The other point to note is that while this is a high speed 24X drive, this "Audio Master" feature only operates at 4X burning, and results in about 63 minutes fitting onto a 74 minute disc.

Seems like a very good drive for those considering buying something, although a bit more expensive than most.

 

Has anyone bothered to, or has been able to set their offsets in EAC? I haven't been able to find two CDs with identical offsets as of yet.

 

The following page lists the offsets, as well as most of the other EAC settings, for a ton of different burners:
http://www.ping.be/satcp/eacoffsets01.htm

 

QUOTE]Originally posted by Paul Christie:
<STRONG>Thanks for the illuminating info. Hey Sckott, what do you mean by your system being "ATAPI-layer hacked"? How is Windows XP handling burning?
</STRONG>[/QUOTE]

Paul,

Windows XP has it's own (correction) ASPI layer that is now proprietary, and doesn't let you use ANY other CD software other than Windows Media Player 8. The internal driver is from Roxio, but the interface is bulky, code-heavy and not indicitive of good control. Yes, it seems easy for the neophite, but I've followed the build of XP for close to a year-n-a-half stint of Betas. Microsoft really made quite an operating system, but this time, the message is clear: Let Microsoft control burning, or GET OUT.

With people I've set up with burners, lately I've found the latest and greatest of burners won't work with XP very well. Really stupid of MS to assume that their proprietary ASPI layer will work with everything. It doesn't, and when you try to install the 3rd party "OEM" in-de-box software, it won't run correctly either. From even the Betas, a few hackers found a way to force-install the older, more powerful ASPI Adaptec Windows NT layer, so that just about anything including EAC, CDRWin and Fureio and Nero will work, AND just about any CD burner will not only be detected properly on the SCSI/ASPI layer, but the software works normally too.

With XP as well, the use of the tried-n-true 3DFX cards are now totally unsupported in 3D mode, no matter how you rip up the code and re-write it. I too have a 3DFX card, and although the card whoops ass (I have the intergrated Philips TV/FM into it too and that works in XP) playing 3D/Glide games don't work period!

And Yama-ha-ha?? I've used many of their EZ series and I've found they were built like the Acer drives before them, and have limited burning abilities and life expectancy. If you want a "Man's CDR" drive, buy a Plextor, HP, or maybe the newer Sonys (Plextor in the highest regard). Audiophile burner?? My butt. It does what the rest of them do, in regards to streaming a 16bit 44.1 to CDA. That technology hasn't really changed since 1989 in terms of how a CDR drive writes to CD. Laser calibration however, which is done before and after the burn, has.

Experiment with the Yamaha if need be, but I have a story too boring and long to describe what I've found in them, and it ain't pretty.

That being said, XP is great once you cut though the limitations with a software-hack saw. Burning on XP is also rock solid. Their Windows Media Player as an interface to burn CDS strictly is not only bad ju-ju, but labours even on a 1.3 Ghz PC with a butload of Ram and an Asus Mo-bo.

You can run EAC and CDRwin (Fureio for that matter) from matchbox-sized resources withas little or as much control as you want.