Ones and zeros recorded on CDs

[mrfeedback]

Different laser pickups sound different.
Also I am able to change the sound of laser pickups.

Eric.

[SY]

Vic, that makes zero sense, theoretically or otherwise, from anything known about polymer processing. Or anything known about chemical/physical processes and rates (Arrhenius, anyone?).

There's a big difference between "some people hear a difference" and "some people claim to hear a difference."

[mrfeedback]

"There's a big difference between "some people hear a difference" and "some people claim to hear a difference."

Sy, would I be right in saying that you fit neither category ?.

Eric.

[SY]

With respect to what? Frozen CDs?

[vic2]

SY,

I'm not a polymer expert. I'm just relaying the arguments that I heard. I try to be as open minded as possible.

I personally think that a neat test would be to microscopically look at a CD, freeze it then look at it again. If there is no discernable difference, then the freezing process would be DIY snake oil. Unless, of course, people here differences. But, again, people say they hear differences for a lot of reasons. Some of which should make no physical sense at all.

[SY]

Polymers are one of the few things I do claim to be an expert at (my Ph. D. dissertation was specifically about the interaction of polymers with infrared light), and I can assure you that these arguments are doo-doo, to be kind. You may well see some differences between a pre and post freezing CD, but they'll have more to do with the shock of the treatment than anything else and they won't matter a bit (ouch, bad pun) to what the laser does.

The true test is one in use; if I give someone 5 discs that were frozen and 5 discs that weren't, can he reliably tell me which is which by listening or measurement of the CD player waveforms? When someone runs that test properly and reports the results, and the results hold up to replication, then it's worth doing some serious investigation. Until then, you should consider this as one more example of the voodoo that has poisoned high-end audio.

[Steve Eddy]

Originally posted by vic
But, again, people say they hear differences for a lot of reasons. Some of which should make no physical sense at all.

Like putting a photograph of your audio system in the freezer to make it sound better?

Peter Belt has been proving this for years now. You can't get more outlandish than what Belt has been selling over the years, yet there are many people who swear by it.

Because there is so much psychology involved in our perception of sound, you can offer up literally anything. Just make something up out of thin air. It doesn't actually have to do anything, yet if you get people to try it, you'll always find a good number of people who purport it to have made a significant improvement.

If you want a good laugh (and further proof that you can dream up literally anything at all), check this out:

<a href="http://www.belt.demon.co.uk/whatamess.html">WHAT A MESS!!!!--An alternative view of reality</a>

se

[Guido Tent]

Originally posted by Henckel


I do not agree. A CD player has a master clock which clocks out the read bytes(PCM data) from a FIFO buffer(towards the DA). The cd players &quot;reader&quot; logic is done in a way that the FIFO is never empty or full. The master Clock is not PLL locked to the reading of the individual data blocks on the physcial CD ( but controlled by the empty/full indications of the FIFO.

In a PC it is the clock source of the soundcard that controls the readout of the PCM data towards digital out or the build in D/A converter. The ripper program that gets the PCM data is controlled in very much the same way as the fifo above or just read once and for all to memory.


Having said that the jitter of the master clock is audible but should be the same wheter its original Cd or a copied one( for one specific set of components).

Hi

The master clock ofcourse is the same (though still contains too much jitter)

The above described fifo works fine but has limitted atenuation.

Starting with about 10 to 20 ns pit jitter (depending on drive, media etc) still too much jitter will ripple through.

If not sufficiently attenuated, it will obviously lead to distortion at the actual D to A conversion, which ofcourse is audible.

Besides that, different media are different (!). This may lead to

- different pit jitter values
- different behaviour of the servo's of the playback module (which induces different jitter as the hardware of most CD players is not carefully designed)
- different jitter patterns due to different prints at the top of the disc

etcetera

Different discs / copies / prints or whatever very likely sound different. Those not able to hear the differences are lucky, they can stick with cheap CDR's and writers, and do not mind buying print nr 1 or nr 10.000 from their popular artists.

Needless to state that CDRW discs sound better than CDR's as the RW media is far less critical towards writing power and write strategy.

best regards

[Pjotr]

Hi,

Here is some interesting reading:

http://www.exactaudiocopy.de/eac13.html

http://www.cdrinfo.com/Sections/Arti...Tests&Series=0

[Guido Tent]

Originally posted by Pjotr
Hi,

Here is some interesting reading:

http://www.exactaudiocopy.de/eac13.html

http://www.cdrinfo.com/Sections/Arti...s&amp;Series=0

Hi

Here is another one

http://www.cdrinfo.com/Sections/Arti...riting+Quality


for those who do not know me: I design Optical PickUp units for recordable DVD players and drives at Philips Optical Storage.

best regards,