Highlighter enhancing CD playback?

[BBB]

Dats right. Now heres one type of highlighter used

to focus on one harmonious point of convergence.

And theeeeen? Stir fried vegetable Thing anyone?

[D-MAN]

I have to say that for once, RAY is WRONG!! What's the world coming to?!

I have worked for 18 years in the computer world as a programmer, and I have to say, the DATA is NOT the same!

2 reasons:

1) burning a CD is a completely different process than PRESSING a cd (from a glass master as mentioned above).

2) reading a burned cd is different than reading a pressed cd. The materials involved are different as is the reflectivity quotient.

Which brings us to the current question about the magic marker on the rim of the cd having an effect as to its playback. The answer is YES, there is an effect due to the change in reflectivity of the laser in the stratum of the cd (that is, the loss of light through the rim is reduced)as well as in the transport drive of the particular cd player. This is clearly noticable. I tried it but found that it DEGRADED the sound, rather than helping it. But try it for yourself...

I also have to argue that in THEORY the data on the 2 types of cds may be "the same" but in practice, it just AIN'T SO. There are many other variables involved, such as the quality of the burner, the quality of the player, the quality of the cd material itself, and the quality of the "reference" audio system used for comparisons that it may not be proven one way or the other.

Burning a cd on your computer is going to produce a less valid "data" copy than the commercial pressed version.

If you continue to copy a burned cd as a source genrationally, you will find that the old tape generation degradation will also become apparent. This is why NOBODY offers burned cds commercially as well as it being slow. The burning of a cd is enherently lossy for complex signals. There are algorythyms built in to the player to "fill in" the missing elements based on what it finds in close proximity.

There is alot of fuzzy logic involved, and that ain't signal, dudes...

Burned CDs

==========

1) source laser - low quality LED

2) target laser - low quality LED

3) electronics - as cheap as they can make 'em.

4) algorythyms - as cheap as they can make 'em, too.

4) the light sensitive medium itself is inherently lossy

Try this, but you have to have a system capable of reproducing the results ACCURATELY:

Take your favorite commercially produced cd and burn a copy.

A/B them on your audio system. They will be different sounding, especially in the low level detail...then burn a copy of the copy. A/B that to the original pressed cd.

We have had the discussion before about the blind a/b/x testing, so I will leave all that up to you, but for me, I'll take the pressed version over the burned one anyday.

DM

[cluless]

I'm going for a band of duct tape around the edges. I'm still having problems with the prototype...the drawer keeps jamming. Oh Well.

[Ray Garrison]

D-Man,

Cool.

Let me modify what I said somewhat.

If the datastream (actual data frames) recovered from the burned CD and the original CD *WERE* bit for bit identical, it would still be possible for the two CD's to sound different due to effects not related to data errors, but rather related to issues like different jitter characteristics.

[Frank Speaker]

D-MAN:

This might be a dumb question but arent the concerns for Music CD copies different than data CD copies?

I have a Yamaha CD burner, considered good quality and I think it checks the burn for errors and then reports any it finds.

Should I be concerned when backing up my computer onto a CD that I am losing data and will have errors in especially important things like numbers and calculations?

[Audible Nectar]

I am not experiencing the phenomenon of generational loss from CD copying. Why?? I use Exact Audio Copy to rip my CD originals. It is the ONLY software I am aware of that verifies that you got EVERYTHING in the rip. I have personally used it and verified it's accuracy by comparing MD5 signatures on the original and copy - they are thus proven to be the same. Rippers are usually where the problem is - not the burn.

For a great primer on this program - how to use it, and why you want to, go here: http://www.chrismyden.com/nuke/modules.php?op=modload&name=Elite_DAE/eac&file=index

[WMcD]

I would like it if someone could point me to more information on this.

I will use whatever software came with the CD burner to make a back up copy of a large application program and or file data on a CD-R. The back up copy works fine. So it seems to me that no data is lost.

I use the same equipment to make a back up copy of a CD with music. It sounds fine to me. Yet people say there is data lost. How is this different than the first instance.

Gil

[BBB]

Bunk! Ive tried all those tricks with this disc and it

still sounds like something I found in a garbage can.

[formica]

----------------

On 5/14/2004 9:27:14 PM Ray Garrison wrote:

If the datastream (actual data frames) recovered from the burned CD and the original CD

*WERE*

bit for bit identical, it would still be possible for the two CD's to sound different due to effects not related to data errors, but rather related to issues like different jitter characteristics.

----------------

I don't mean to rain on the parade... but "jitter" in CD playback is the result erroneous data (either when written or read). I agree that the source of the problem may be quite different such as timing errors during reading, uneven lengths of the pits and lands on the disk, an additive timing error also on the disk, etc...

The end result is the same; the data recieved at the DAC from the jitterless original is not identical to that read from the jittery copy. A check sum on the troubled player/disks will reveal an error.

A couple more unrelated points I'd like to add are:

- Both data and audio CDs contain an error correction algorithm. Not all players are equally effective at dealing with them.

- Transports which can't read CD-R simply weren't designed to deal with the format's different reflectivity. This is in no way a sign that it reads the pressed CD more accurately. Most modern inexpensive/expensive transports can read data from either type of disk.

- Burning CDs is not as simple as writing data to a hard disk (yet)... and having a good PC without too many background programs helps. Most modern burners have a larger memory buffers than those from several years ago... so they have helped improve reliability.

That said, I used to have a burner which produced CDs that suffered from jitter. It was most apparent in the last songs contained in the data which surpassed the red-books 640MB. I figure it was probably due to a cumulative timing (spacing) error when burning the disk. After updating (flashing) the drive's controller, the problem went away.

My opinion is the most important factor for CD playback is the original recording (by a long shot) and then the DAC.

Rob

[artto]

Tim Babb...SHAME ON YOU! (again) (I've said this to Tim before on same subject)

The green marker ink on the edges, and virtually all of these so-called tweaks, these are all squirrelly personal theories that some inept doops (tweaks) who in reality don't know **** have come up.

Bring those Wrights over to my place, & you, me, and few other folks will put your CD perceptions to the test. At this point in time I'm inclined raise the anty and challange you to put your money where your mouth is. Blind test time baby!

Further more, commercial CD are, as you said, "pressed" making 'pits' in the CD. This surface is covered with a clear protective layer. The pits themselves do not become less defined over time. Changes in temperature/humidity will affect the pit size & depth more than anything the low powered laser will do over time. Although you are correct in that the glass master (just as in pressing analog LPs) will deteriorate over time. However any surface scratches or other deterioration of the protective surface over time due to use may affect CD performance in that the CD player's error correction must work harder, interpolating more & more data to 'fill-in-the-blanks" (the lost or corrupt data). In fact, if it were not for the error correction process, CD playback would be virtually impossible. This, at least in part, is whats responsible for CD players sounding different. Its their ability to error correct. They all don't use the same error correction process or algorithm. In fact my old Revox (circa 1985) uses only a simple solomon cross interleave code (like regular computer data disk) as error correction.

CDs that are "burned' do not have 'pits' as such. When you 'burn' a CD-R you are not creating 'pits'. CD-R use organic dyes which change their reflectivity value when "shot" with a laser. This is probably why CD-R have more problems with playback on certain equipment. The simple reflectivity change is not as easy to interprete as actual pits. And I should know. I've only burned at least a few thousand CD-R of my own recordings that I have mastered (known value & sound quality as well as knowledge of what the original performance was like).

As for copied CDs sounding better, sometimes this can actually be the case depending on how the process was done. There seems to be some kind of enhancement process that takes place with WAV files. For instance, the first time I noticed this was when my band made it's first CD. It was recorded professionally at a recording studio on 24 track ADAT (3 8-track ADAT synced together). From there the ADAT was transferred to 2-channel DAT. The 2-channel DAT then went to the mastering studio for further 'tweaking' (very minor adjustments in frequency response, cross-fades/fade outs, spacing between tracks, track sequence, etc). This DAT went to the CD production/manufacturer. When the CDs came back, I was amazed that the (pressed) CDs sounded better than the DAT master. There is no disputing this. I repeatedly listened to the DAT master on my system, going back & forth between my place & the studio when the recording was being made, suggesting changes until everything sounded right. Having both the original master DAT to produce the CD & the final pressed CD at my disposal, as well as being intimately invovled in the entire recording & mastering process, it was immediately clear that the final production CD sounded better. Don't ask me why, because I don't know. But I have heard the same thing from other musicians I know.

[sheltie dave]

Guys, guys, guys,

the ultimate test is the marketplace. IF there was some validity to this 1985 hash brownie, then there would be a company started up with an automated green highliter system that could do a thousand CDs a minute...they would charge an extra two dollars a CD...and we would all have green highlited CDs...and three guys would be multimillionaires living in Miami Beach.

Good ideas that work, are cheap to create, and have a mass market just by capturing 1%, or 0.1% of the market, make people millionaires. I still have my pet rock from 1975 or so. Mood rings were big. Bell bottoms were a success. Green highlited CDs are a marketing ploy created by highliting companies.

If you want better sound from your CDs, go to a tile and counter marble place, pick up a slab of marred scrap marble or granite for $5, buy four isolation feet, and VOILA!, you have something that has a positive effect on listening quality that most everyone has reached a consensus. This actually does work, and if you don't like it, you now have a cold surface that doubles as a pastry making slab!

[Marvel]

artto,

It is probably the last bit done by the mastering lab. Multiband compression and eq tweaking to make the music sound the best. And golden ears. I am amazed at what these folks can do to an 'okay' tape, be it analog, dat, cd. Mastering labs are worth their weight in gold, and fortunately for musicians, they don't charge what they probably deserve.

Marvel

[artto]

I know what you're saying. But I have the tape from the Mastering Lab (studio). Thats the tape that was sent to the CD manufacturer. The CDs came back sounding better than the tape from the Mastering Studio