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Topic: Could there be possibly a reason why a SHM-CD is better? (Read 7746 times) previous topic - next topic
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Re: Could there be possibly a reason why a SHM-CD is better?

Reply #25 –
Hmm, my lazy read on Wikipedia (https://de.wikipedia.org/wiki/SHM-CD) reveals, that instead of using the regular polycarbonate, they use a more translucent plastic, normally used as the screen in LCDs.

So higher transparency, so potentially SNR in the pickup system. Supposedly, the plastic is easier to work with when CD are stamped.

That's the only change, compared to a traditional CD. Personally, my concern would be how good that plastic works with the reflective layer, and if they need a different glue, etc. Also, how scratch resistant is it. Granted, PC isn't the best when it comes to being resistant to scratches, but you can always go worse ¦D

It's nice that they managed to potentially improve CDs, while keeping them backwards compatible, but I don't think it really means anything in the industry. People don't really buy CDs anymore, so it's kinda pointless, I'd say.

Re: Could there be possibly a reason why a SHM-CD is better?

Reply #27 –
@Porcus
Would you like a tissue?

"... I did not even check"
Of course you didn't.  That would be out of character.

Re: Could there be possibly a reason why a SHM-CD is better?

Reply #28 –
The cynic would assume, that LCD plastic is probably cheaper than CD-Plastic by now. And they switched simply to make it cheaper for them, but also increase their profit margin, claiming it's better ¦)

Re: Could there be possibly a reason why a SHM-CD is better?

Reply #30 –
Quote from: ajinfla on
Quote from: apastuszak on
When I fire up Foobar 2000 I tend to hop around all over the place and pick songs I know I like.  I dropped a receiver and a CD player on my desk and now when I get up in the morning, I walk over to the CD rack and pick 8 CDs and take them to my desk and play them.  Forces me to listen to the whole album and also albums that might be outside my comfort zone, or ones I consider "safe."
Heck I own a bunch of thrift store CDs that I have never listened to.  This is forcing me to enjoy my musical collection.
  Masochism is symptomatic of audiophilia.

My music system is beholden to me.
 
 In his/her case, that sounds more like "In Soviet Union we are beholden to sound system." :D
Listen to the music, not the media it's on.
União e reconstrução

Re: Could there be possibly a reason why a SHM-CD is better?

Reply #31 –
Does a scratch that is detrimental to playback  cause a CD to skip before  it is large enough to cause a non-correctable  error.

Re: Could there be possibly a reason why a SHM-CD is better?

Reply #33 –
Is the tracking system less robust than the data error correction system. If it is then,  the CD would skip before an un-correctable data error occurred.

Re: Could there be possibly a reason why a SHM-CD is better?

Reply #34 –
That's a good question, but the CIRC is built into the data stream, so I'm thinking the player will attempt to correct the bad data that has already been read before trying to grab new data after the physical skip.

Then again part of the recovery data could be located in the area being skipped, in which case the tracking problem occurs before the player fails to correct a logical error.

So, I'm not really sure.

Re: Could there be possibly a reason why a SHM-CD is better?

Reply #35 –
Quote from: polemon on
Hmm, my lazy read on Wikipedia (https://de.wikipedia.org/wiki/SHM-CD) reveals, that instead of using the regular polycarbonate, they use a more translucent plastic, normally used as the screen in LCDs.

So higher transparency, so potentially SNR in the pickup system. Supposedly, the plastic is easier to work with when CD are stamped.

That's the only change, compared to a traditional CD. Personally, my concern would be how good that plastic works with the reflective layer, and if they need a different glue, etc. Also, how scratch resistant is it. Granted, PC isn't the best when it comes to being resistant to scratches, but you can always go worse ¦D

It's nice that they managed to potentially improve CDs, while keeping them backwards compatible, but I don't think it really means anything in the industry. People don't really buy CDs anymore, so it's kinda pointless, I'd say.

Well, I think this post sums it up best.

What I am wondering if ever someone tried to sue these magazines. The claims that they suggest are not able to withstand scientific proof.

Re: Could there be possibly a reason why a SHM-CD is better?

Reply #36 –
First -- I want to make sure that everyone believes that I don't THINK that an SHM-CD is better...  However, is there any way that it JUST MIGHT BE BETTER, especially if a special player is  used?  Possibly...  If the material is 'perfect', then the ECC is not needed.  It is JUST POSSIBLE (however unlikely) that the ECC space is used to encode additional audio data.   I don't think that is what is happening, but just a possibility.  That is the ONLY WAY that more data (higher quality) can be crammed into a CD.

John
 

Re: Could there be possibly a reason why a SHM-CD is better?

Reply #37 –
According to this paper , quote from Phillips,  a non correctable  error causes a skip.
http://www.cs.bath.ac.uk/~pjw/NOTES/198-DM/ch2.pdf.

And so if a CD is not skipping there are no errors in the data.

Re: Could there be possibly a reason why a SHM-CD is better?

Reply #38 –
Depends on whether you view linear interpolation as a skip, which often times is unnoticeable.

Perhaps you can quote the specific part rather than posting a link to the paper requiring others to dig for it for themselves.

Re: Could there be possibly a reason why a SHM-CD is better?

Reply #39 –
The CIRC is  powerful as the data for a single sample is physically  spread over the  circumference.

The pertinent point is the situation where the music skips  from a scratch - as in where the music audibly jumps or repeats.
Do  CDs ever produce corrupted audio after the DAC when  the music is not  skipping,  ie whether or not the quality of the plastic can  improve the audio quality  if the CD is not skipping.

auto word search the paper for "skip"

Re: Could there be possibly a reason why a SHM-CD is better?

Reply #40 –
Quote from: KMD on
if a CD is not skipping there are no errors in the data.
This is logically identical to saying, "If there are errors in the data then the CD is skipping."

I believe I understand CIRC well enough to know that this simply isn't true: errors can occur without the necessity that there was mistracking.  Please quote the portion of the paper that specifically says otherwise.

I'm willing to buy off on the idea that mistracking can cause uncorrectable errors in the data, and for the sake of argument, that mistracking will always cause uncorrectable errors in the data; but that is not what you are claiming.

Re: Could there be possibly a reason why a SHM-CD is better?

Reply #41 –
Quote from: Chris Norman on
Quote from: polemon on
Hmm, my lazy read on Wikipedia (https://de.wikipedia.org/wiki/SHM-CD) reveals, that instead of using the regular polycarbonate, they use a more translucent plastic, normally used as the screen in LCDs.

So higher transparency, so potentially SNR in the pickup system. Supposedly, the plastic is easier to work with when CD are stamped.

That's the only change, compared to a traditional CD. Personally, my concern would be how good that plastic works with the reflective layer, and if they need a different glue, etc. Also, how scratch resistant is it. Granted, PC isn't the best when it comes to being resistant to scratches, but you can always go worse ¦D

It's nice that they managed to potentially improve CDs, while keeping them backwards compatible, but I don't think it really means anything in the industry. People don't really buy CDs anymore, so it's kinda pointless, I'd say.

Well, I think this post sums it up best.
+1