Hello,

I have some questions. I have around 5-10 rare audio cd's and I would like to back up these Cd's. What I wanted to know is if I will get the exact clarity and quality if I copy these Cd's like it is present in the original. Will there be any loss in the quality? Also, what would be the best program to take the backup of the CD's. I have EAC, my burning software Nero and CloneCD. Which of these software will do the job. I have a Plextor 24/10/40. I have seen that it is considered a good writer for taking backups of CD's. Also, does the CD media matter (like blue surface or golden surface). I currently am using Mitsubishi Chemicals manufactured Cd's which has a blue surface.

Thanks in advance,

Aquarius.

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Please use a more describing title next time
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It's easy to know: use "Compare WAVs" tool in EAC.
Extract the WAVs from the originals and the copy and compare them. There will be differences in a very small offset, but don't worry about it: usually the data is the same.

EAC if you know how to configure it.
If you have a modern Plextor use PlexTools: easier and more accurate.
Feurio will also report C2 errors with that drive if the CDs are in bad condition and there are errors.

Media matters. I like Mitsubishis. They are resistant and compatible. I don't know which ones are the best.

There will always be a little loss of quality, since the channel separation of an audio cd on CDR is not as good as the channel separation of the original disc.

The quality of the sound, depending on channel separation (among other factors) isn't bound to a certain disc, but it depens from the writer used...

...........@ Dee-ehn : what factors??PLEASE?!..........

??????

@stupidass: I meant that channel separation is not the only factor that determines the quality of audio

@alexnoe: read this in a hifi mag, believe it was stereoplay; most people do not mention the difference, but it seems there are audiopheliacs who do so...

I am veeeeeeeeery careful with any kind of magazines...if you find the article (even if it is Dutch; i'd find a way...), could you send it to me?

BTW, it has already been proven that so called audiopheliacs hear things which don't exist (they only claim to hear differences if they know what is played...but fail to distinguish 2 discs if they don't see them )

I don't see any reason at all to cause trouble with channel separation anyway...that's why I'd like to see that article

Well if it was in Stereoplay, ot was in German, so that's good for you. As it dated back from, I guess, 1999, I don't know if I still have it! I'll look for you as soon as I get home..

Here's something similar I found with Google (in fact, there story is about the same, though a little compressed:

From this site
Hope this will help you out in case I don't find the article...

Yes, the signal will usually be weaker, but a few brands of media do not show this behaviour (such as Mitsui SG Gold Ultra). If the signal is too weak, then the disc can skip, produce random noise or may not be recognised at all.
It is a bad idea to begin a nonsense sentence with "As we know" . Audio is just stored with 2352 bytes per sector, not Mode 2 Form 2 or any other "Mode" or "Form".
If this were indeed a cause for inferior audio quality, then you could measure it with a plain C2 scan
More C1 errors, yes, probably. But more uncorrectable errors? If they occured, a C2 scan would show them.
It does. It shows that the author has no clue as to what he's talking about...

That may be, but I know for sure these values are in the CDD3610 manual as well (I've had a 3610, rebadged as Traxdata ). Why?

I wouldn't ask you for the article if I knew

Has anyone ever confirmed these measurements? Or did Philips include this "info" to make "audiopheliacs" buy original discs only by suggesting them cd-r's to be inferior

Seriously, I don't know

It sure is plausible, but I do not think so! Philips (probably) makes a lot of more money on CDRs than on audio discs.....

Nowadays: yes
When the Philips CCD3610 was up-to-date: i don't think so

I think the HP7100, which I had 5 years ago, was also one...

I've always had the feeling that audio cd-r have a little bit more trebbles than original audio cd.

I can notice that when i check that there are no errors on my cd-r (and with UltraPlex 40 and Plextools or EAC, errors are very, very rare). Sometimes, when i think i've found an error, i listen to the original cd. I can also notice the suspect noise on it but that's always smoother on pressed cd.

It's often guitar sound or audience sound in live cd.

I can report that with tracks extracted with Sony and Plextor cd reader. Maybe other readers are better.

Anyway, i can only hear that with a good hi-fi material and that's not annoying at all.

Can you here it blindly? Meaning: Ask someone to replay the discs randomly 10 times, without telling you which one.
If you can always say which one it is, then, and only then, you can here it

AFAIK, Philips sold their record company before they released the CDR for the big public.

Polygram used to be Philips as well, I don´t know if it still is Philips (or if it even still does exist)...

Sure thing the blind test would be very difficult. Still i confirm what i said.

But my experience is quite limited : my first Sony scsi and my UltraPlex. And i can notice that phenomenom only with a very few discs : 1 for 50 approximatively. I have to find a very specific sound (someone coughing in the audience, ...) to notice the difference.

Of course i can't notice any difference just by hearing a pressed cd and its cd-r copy.

I can also remember that "carbon" cd-r (Hispace) were supposed to have a smoother sound. I never believed that because i think it's a reading problem. But it demonstrated that the problem was known.

Plextor and Yamaha also claim that their burners provide a better sound.

Improving sound can be understood in two ways : the audiophile way, supported by Bob Katz (digido.com goto "articles/Jitter", and "FAQ/Jitter") supposes that the playback is bit perfect, and that the sound is affected by the incoming jitter into the DAC. And the "engineer" way that states that the jitter is completely eliminated by the DAC, but that if read errors occur, the digital values are interpolated, thus different than the original ones.

Yamaha's position about Advanced Audio Master is unclear (from http://www.yamahamultimedia.com/yec/tech/aam_01.asp# )
Only the "audio fidelity" argument is on the audiophile side, but it can be understood in the two ways. Maybe, consious of the arguments against the audiophile position, they deliberately chose an ambiguous statement, so as to please audiophiles, but not upset engineers.

Oliver Friedman and I have checked that the digital playback of our CDRs in our CD Players (a Sony and a Yamaha CDX860) was error free, comparing the SPDIF output to a secure audio rip done with EAC. I checked a 24x burned CDR (an "audiophile nightmare") for 4 minutes of playback. This makes impossible the slightest difference in frequency response.

The Philips paper (I could never reach it since it is in a restricted aera of their website) was quoted in EAC's mailing list by Mike Richter, which lead me to perform the same experiment.

According to the measurments I made, recording sines from the analog output of a Yamaha CDX860 CD Player into the 24 bits 96 kHz analog input of a Marian Marc 2 soundcard, then performing analysis with SoundForge 4.5, and taking into accound all sources of error, such as quantization noise, size of the samples, and especially alias effects, I came to the conclusion that the frequency response of the analog playback of a CDR deviates no more than 0.5 db from a flat line until 20,000 Hz, which completely dismisses Philips statement about -2.5 db at 16,000 Hz.

This result was to be expected. As no digital error occur, the curve reconstructed by the DAC is exactly the same as long as the digital data is the same, the jitter having no significant effect on it according to various sources. Though the only number I could get about jitter was 10ps for high end audiophile transports, with the warning that it is only the average value; and 1000 ps for DAT decks, that would make them "worse" than CD Players (infos from digido.com).
All the details and calculus about my measurments here : http://pageperso.aol.fr/lyonpio2001/cdr/cdr.htm

I have found one explanation why a copy could sound worse (provided by cdrtools author): It seems good to me.

There is a pre-emphasis flag, which is present in the TOC as well as in the subchannel data of the track.

Some pressed audio CDs contain different values there (which is technically wrong, but occurs).

If the software which you use does try to fix this (e.g. take the value from the TOC and copy it to the subchannel), it could take the wrong value, and would then create a CD which sounds differently. Not due to reading problems, but due to accidently "repaired" data.

When using CloneCD, it should not try to fix anything, but should just copy the broken flags. Then, the copy should sound exactly like the original.

What is the purpose of pre-emphasis? What are its effects?

I've only found this:
http://www.cdrfaq.org/faq03.html#S3-12
"Preemphasis has been used since the earliest days of commercial recording. In general, the high-frequency content of the music (or whatever) being recorded is low and the noise is high. Therefore, treble was boosted and lows were cut by a preemphasis curve which was removed in playback. The standard RIAA curve for turnover and rolloff (the amount and frequency for treble and bass, respectively) was not accepted universally until the 50's, and some fine preamps offered selectable values with presets for the common curves into the early transistor era."
Different values along the same disc? Isn't it just a flag for the whole disc?

Do you mean that CloneCD could work better?
CDRWin and Feurio copy this flag...

It's one flag, but it's stored in the TOC and in the q-subchannel of each track.
These two should not differ (they indicate the same thing), but sometimes they do.

CloneCD would then probably work better because it certainly just keeps both values (although only one is correct)
Which one? The one from the TOC, or the one from the q-subchannel, or both?

From http://www.digitaldisc.com/cd-audio.html :

"Add 2 seconds (minimum) pause time between tracks when there is an emphasis change. "

From : http://www.digido.com/index/pmodule_...er_page_id=20/

"There have been many problems with the use of emphasis (loss of headroom, wrong PQ codes, inaccurate deemphasis circuits) and therefore most CDs made today do not use emphasis."

There is a frequency response plot of de-emphasis at the bottom left of page 5 of this doc : http://dxr3.sourceforge.net/download...re/PCM1725.pdf

The response is actually -10 db at 16 kHz (and already -6 db at 5000 Hz), thus it can't explain the subtle differences between original and copy.
If there is an error in emphasis the copy sounds so bad that the copy has to be redone.

By Pio2001:
I'm no hardware expert, but there would be unlikely many or even any jitter at all with the new drives. They have better handling to prevent jitters. Obviously correct me if I'm wrong:

Main causes of jitter:

1. If drive stops streaming, i.e. if sectors are requested separately
2. defects in pits/land on CD
3. bad drive mechanism including lens design

None of the above applied did it?

For people who don't know:
Jitter means skipping or overlapping of audio data. The drive can prevent jitters occuring on CD sector frame boundaries by comparing the subchannel data. If incorrect then hardware tries re-reading the sector with an offset.

Very old drives like quad speed ones I think will have jitter - you should test with these ones. But you still need to request sectors separately and not using the play audio CD command - this is streaming - less or no jitters at all. Requesting sectors separately has it's problems, this will not use interpolation.

I really don't expect an audible difference between a well copied disk and the original.

It is all going to be a matter of C2 errors. Assuming no copy protection, a newish, good quality writer, quality CDR's written well within their speed capacity, and a good copy program, all should be well.

It is possible that you could get a difference with a player that has trouble reading CDR disks. The image is more difficult to read, and the drive has to adjust to the slightly different signal. Older disk drives may be a little dodgy.

If you are not careful with you tests, there is another source of difference:

The conversion to analogue signal is normally done on the CD drive. There are ways to get the signal out digitally, and do the conversion with the Sound Card, but they are not normally used. You could expect audible differences between CD drives, even on the same computer. You could also expect differences between the sound played directly from the disk, and one converted to a wave file, and then played. It would then be using the Sound Cards DAC (Digital to Analogue Converter) rather than the CD drive's.

Frankly, I suspect that is what happened with the Philips report. The differences quoted look very much like different DAC's.