Are people really this stupid?
Discussion
I know the answer is going to be yes, but surely this was done as a joke, which took off with the Audiophile brigade..
http://cgi.ebay.co.uk/Audio-Desk-System-CD-Sound-I...
The "systeme" cleans oil off a CD (a bit like a Kleenex i guess) and cuts a 36 degree bevel on the edge which makes the digital sound even better.
Like religion though, as much as you explain that what they are talking about is complete balls and can't possibly work, more and more people will tell you of the definite improvement they heard, so it must defy all manner sensibility.
I can't help thinking that the companies selling this crap are laughing at all their customers as they flock to buy this crap.
http://cgi.ebay.co.uk/Audio-Desk-System-CD-Sound-I...
The "systeme" cleans oil off a CD (a bit like a Kleenex i guess) and cuts a 36 degree bevel on the edge which makes the digital sound even better.
Like religion though, as much as you explain that what they are talking about is complete balls and can't possibly work, more and more people will tell you of the definite improvement they heard, so it must defy all manner sensibility.
I can't help thinking that the companies selling this crap are laughing at all their customers as they flock to buy this crap.
Well, back in the day, it was said going round the edge of CDs with a black marker did the same thing - blocked off scattered laser light that's transmitted through the clear plastic of the CD.
With a REALLY good system (I'm talking Tag McLaren CD and amp, and Monitor Audio speakers) there is a marginal difference to magic-markered CDs. I've heard it. It also depends on the CD - some CDs are well produced, but most are crap having been engineered by some old geezer with hair in his ears.
The crap most people use to listen to CDs with, it'll make bugger all difference, though.
With a REALLY good system (I'm talking Tag McLaren CD and amp, and Monitor Audio speakers) there is a marginal difference to magic-markered CDs. I've heard it. It also depends on the CD - some CDs are well produced, but most are crap having been engineered by some old geezer with hair in his ears.
The crap most people use to listen to CDs with, it'll make bugger all difference, though.
Er sorry a qualified no !
Cleaning your disc will help . just like cleaning your glasses
use the same stuff too. Just helps the laser read the pits better and helps avoid the error correction. Think this can actually be measured digitally (less jitter)
CDs are not always made very well, the device shown cuts the edge clean and makes sure your disc is round. This helps the player spin the disc. Never heard the effects so can't comment. Might help some discs/players but not likely to be a great difference.
Cleaning your disc will help . just like cleaning your glasses
use the same stuff too. Just helps the laser read the pits better and helps avoid the error correction. Think this can actually be measured digitally (less jitter)CDs are not always made very well, the device shown cuts the edge clean and makes sure your disc is round. This helps the player spin the disc. Never heard the effects so can't comment. Might help some discs/players but not likely to be a great difference.
P700DEE said:
Er sorry a qualified no !
Cleaning your disc will help . just like cleaning your glasses use the same stuff too. Just helps the laser read the pits better and helps avoid the error correction. Think this can actually be measured digitally (less jitter)
CDs are not always made very well, the device shown cuts the edge clean and makes sure your disc is round. This helps the player spin the disc. Never heard the effects so can't comment. Might help some discs/players but not likely to be a great difference.
A clean CD requires less error correction on the part of the CD player.Cleaning your disc will help . just like cleaning your glasses
use the same stuff too. Just helps the laser read the pits better and helps avoid the error correction. Think this can actually be measured digitally (less jitter)CDs are not always made very well, the device shown cuts the edge clean and makes sure your disc is round. This helps the player spin the disc. Never heard the effects so can't comment. Might help some discs/players but not likely to be a great difference.
If the laser fails to read the CD correctly, it inserts a bit by means of interpolation (by guessing - should it be a '0' or a '1' hmm..).
So a clean CD (and laser pickup) will indeed improve sound quality - but only if it was dirty in the first place!
So yes - it can be possible to hear a difference - but only when the CD is very bad.
Some technical info on the error correction system can be found here.
ETA: Get a DVD and smear it full of greasy fingerprints (make it bad) and then watch it. You'll see 'dropped frames' for sure (I use the term with care). Same theory applies as to audio CDs.
Edited by TonyRPH on Monday 30th August 16:47
neilsfishing said:
....it will all die inc CD’s, as with cylinder vinyl stuff my dad had
That's what was said about vinyl 25 to 30 years ago.I'm guessing that CDs will still be around for a few years yet, but probably in smaller volumes, sold only in specialist shops.
Just like SACD / DVD Audio was going to sound the death knell for CD but it didn't.
Both have spectacularly flopped.
I've been over this before at some length. Errors and jitter from optical transports can now be 100% corrected by the cheapest of the cheap players like you would find at ASDA for a tenner. Find one with a digital out (Optical or Co-Ax) and hook it to a good DAC. I guarantee there will be no difference between this setup and the most expensive / most renowned optical transport in the world plugged into the same DAC. The only assumption I make is that the disc is not so badly damaged that it's unreadable by the lower quality player.
Improvement of digital audio signals is utter balls in this day and age unless there are very specific circumstances.
Improvement of digital audio signals is utter balls in this day and age unless there are very specific circumstances.
TonyRPH said:
neilsfishing said:
....it will all die inc CD’s, as with cylinder vinyl stuff my dad had
That's what was said about vinyl 25 to 30 years ago.I'm guessing that CDs will still be around for a few years yet, but probably in smaller volumes, sold only in specialist shops.
Just like SACD / DVD Audio was going to sound the death knell for CD but it didn't.
Both have spectacularly flopped.
In the same way Blue ray hasn't killed DVD, because the perceived quality differential isn't great enough to warrant people repurchasing a large library in the higher definition version.
Of course the format war stalled early adopters many who went over wholly digital storage on their hard drive of their media PC, again ease of use.
Put it this way I could happily live without a CD player, especially in the head unit of my car system.
Roop said:
I've been over this before at some length. Errors and jitter from optical transports can now be 100% corrected by the cheapest of the cheap players like you would find at ASDA for a tenner.
I beg to differ.If the data is misread by the transport in the first place, this means error correction will have to insert the missing data.
However.... error correction makes a 'best guess' attempt at replacing that missing data.
So if there was a '1' on the disk and error correction thinks it was a'0' then data has been lost.
This is precisely why devices such as the Logitech Squeezebox and other MP3 players are replacing CD transports.
Simply because all things being equal, they can theoretically deliver a perfect data stream.
So yes - part of your statement is correct - jitter can be corrected - but if data is misread from the media, the system cannot put back what is missing..
Which is why you still get a 'dodgy' picture from a DVD disc that is scratched or has dirt on it.
Error correction cannot replace what wasn't there in the first place...
Edited by TonyRPH on Monday 30th August 20:03
Tony, I agree on the SB reproducing what it's given perfectly as it doesn't have to read from a CD each time but what about the ripping process? Do things like EAC and Accurate rip provide a better copy from the disc. I've been looking into it and it seems to make sense to read and re-read if there are errors and to account for problems off-line so that the copy is perfect? Also the ability to compare with other peoples rips must be useful?
Bullett said:
Tony, I agree on the SB reproducing what it's given perfectly as it doesn't have to read from a CD each time but what about the ripping process? Do things like EAC and Accurate rip provide a better copy from the disc. I've been looking into it and it seems to make sense to read and re-read if there are errors and to account for problems off-line so that the copy is perfect? Also the ability to compare with other peoples rips must be useful?
The ripping process tends to be more accurate, because it isn't real time.So if an error is detected, the laser can be instructed to retry, the number of retries is usually limited in the software. This is how EAC for example claims a bit perfect copy, simply because it'll continue to re-read the disc until either a) it gathers the correct data, or b) it runs out of retries (in which case the data is not perfect).
But with a CD player - the data has to be read real time, so there can be no "oh wait a sec, I can't read this bit", please hang on while I try again.
Some manufacturers (Meridian was one IIRC) designed a CD player that cached the data, so there was a short delay after pressing play, before the music started. So what they were doing, was allowing time for successive re-reads of data, in the event of an error.
ETA: And yes - comparing checksums with other rips can also be good way of verifying the copy - however, there can be quite a variety of different pressings for the same CD which might well confuse things...
Edited by TonyRPH on Monday 30th August 22:06
TonyRPH said:
Bullett said:
Tony, I agree on the SB reproducing what it's given perfectly as it doesn't have to read from a CD each time but what about the ripping process? Do things like EAC and Accurate rip provide a better copy from the disc. I've been looking into it and it seems to make sense to read and re-read if there are errors and to account for problems off-line so that the copy is perfect? Also the ability to compare with other peoples rips must be useful?
The ripping process tends to be more accurate, because it isn't real time.So if an error is detected, the laser can be instructed to retry, the number of retries is usually limited in the software. This is how EAC for example claims a bit perfect copy, simply because it'll continue to re-read the disc until either a) it gathers the correct data, or b) it runs out of retries (in which case the data is not perfect).
But with a CD player - the data has to be read real time, so there can be no "oh wait a sec, I can't read this bit", please hang on while I try again.
Some manufacturers (Meridian was one IIRC) designed a CD player that cached the data, so there was a short delay after pressing play, before the music started. So what they were doing, was allowing time for successive re-reads of data, in the event of an error.
1 - LOADS of CD players can re-read data. There were loads of names for it, but it was basically anti-skip tech.
2 - Although an MP3 player can deliver a perfect stream of 0/1's it will still generally sound worse than a CD due to the compression required to reduce the file size in creating the mp3. If you ript the full .wav file from the CD then (and only then) will you be able to get a perfect stream of 0/1's just as if it was playing from a perfect CD.
TonyRPH said:
Roop said:
I've been over this before at some length. Errors and jitter from optical transports can now be 100% corrected by the cheapest of the cheap players like you would find at ASDA for a tenner.
I beg to differ.If the data is misread by the transport in the first place, this means error correction will have to insert the missing data.
However.... error correction makes a 'best guess' attempt at replacing that missing data.
So if there was a '1' on the disk and error correction thinks it was a'0' then data has been lost.
TonyRPH said:
This is precisely why devices such as the Logitech Squeezebox and other MP3 players are replacing CD transports.
Simply because all things being equal, they can theoretically deliver a perfect data stream.
Networked media players suffer from jitter (and potentially errors) to a much greater extent than a CD player. Fortunately, as with the CD player, they can mostly be corrected. As with the CD, if the read is interrupted and uncorrectable due to (in the case of CD) a badly scratched disc that exceeds the max. number of errors in a block, or (in the case of networked media) something like multiple packet loss, then either of the streams are jiggered.Simply because all things being equal, they can theoretically deliver a perfect data stream.
TonyRPH said:
So yes - part of your statement is correct - jitter can be corrected - but if data is misread from the media, the system cannot put back what is missing.
Again not so. This depends on how many errors are read in a particular Reed-Solomon block (I forget what they call the blocks, it's long time since I studied it). If there's less than a certain number they can be corrected, if there's more they can't.TonyRPH said:
Which is why you still get a 'dodgy' picture from a DVD disc that is scratched or has dirt on it.
Error correction cannot replace what wasn't there in the first place...
Yes it can provided that the errors per block do not exceed a certain number as I mentioned. If they do exceed, then no it can't and the block is lost (Reed-Solomon never tries to guess). The dodgy picture on the DVD only appears when the error correction is unable to correct the block due to number of errors. My original point being that it doesn't matter one iota whether it's a £15 DVD player or a £15,000 DVD player, if it can't read the data leading to more errors than can be corrected, you're stuffed. The cheapest of the cheap players can error and jitter correct 100% (provided the disc can be read by the transport), hence it really doesn't matter what you buy unless your optical media collection is scratched to buggery and requires a particularly precise transport. Even then, there's very little in it.Error correction cannot replace what wasn't there in the first place...
Just like you, it's a long time since I did my CD theory (back in the 80's!).
I shall do some research....
Even so - an error is an error - if the error correction cannot correct it, then you get a glitch (i.e. a moment of non musical sound lol).
I have tried various CD players ranging from £50 to £800 and there is a definite difference in sound quality, when played through the same cables and DAC.
To me, this can only mean that the cheaper players are not extracting maximum info off the disc.
roop said:
You missed the assumption I made of the data being correctable (as in the disc is not so badly damaged it's unreadable). If it's unreadable, it's unreadable - doesn't matter what transport you use.
Indeed I did miss your assumption...roop said:
Networked media players suffer from jitter (and potentially errors) to a much greater extent than a CD player.
Yes but fortunately most (if not all) decent DACS have input shaping etc. to eliminate that as you say.roop said:
This depends on how many errors are read in a particular Reed-Solomon block (I forget what they call the blocks, it's long time since I studied it). If there's less than a certain number they can be corrected, if there's more they can't.
My theory is very rusty, dating back to the 80's. But for some reason interpolation sticks in my mind.I shall do some research....
Even so - an error is an error - if the error correction cannot correct it, then you get a glitch (i.e. a moment of non musical sound lol).
roop said:
My original point being that it doesn't matter one iota whether it's a £15 DVD player or a £15,000 DVD player
Which doesn't explain why I can hear subtle differences between cheap and expensive players, through the same DAC.I have tried various CD players ranging from £50 to £800 and there is a definite difference in sound quality, when played through the same cables and DAC.
To me, this can only mean that the cheaper players are not extracting maximum info off the disc.
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