HI-FI Tweaks, myth or fact!
- Thread starter Monstermunch
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It came out before copy protection. Was meant to stop stray light escaping from the edge of the disc..... Made a huge sound improvement,.... said so in a magazine !!! 
My favourite was the one having to line up all the screw heads on every light and wall and socket in the house
My favourite was the one having to line up all the screw heads on every light and wall and socket in the house
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dmpoole said:
Now you're just taking the ****
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DRZ might be able to answer this, being as he's a scientist an' all
But the idea behind the green thing sounded plauseable, just didn't make any noticeable difference to my ears.
I had read somewhere (not just a hi-fi mag) that bright green was the only thing that would render a laser signal inert. So by using green paper in the cd drawer or green pen on the disc it would soak up stray lasers and help to keep the returning signal pure, instead of picking up distortion from inside the transport.
Makes no difference to me but my mate keeps going on about it and has green paper bluetacked inside his £1100 Cyrus CD8X drawer! and I need to tell him he's a PLANK
But the idea behind the green thing sounded plauseable, just didn't make any noticeable difference to my ears.
I had read somewhere (not just a hi-fi mag) that bright green was the only thing that would render a laser signal inert. So by using green paper in the cd drawer or green pen on the disc it would soak up stray lasers and help to keep the returning signal pure, instead of picking up distortion from inside the transport.
Makes no difference to me but my mate keeps going on about it and has green paper bluetacked inside his £1100 Cyrus CD8X drawer!
and I need to tell him he's a PLANK
Never tried any of the mentioned changes.
Interesting note on the green pen thing is that Naim paint the insides of their CD mechanisms in matt green, which they claim helps. No idea if that's them jumping on the bandwagon or not.
Isolation and power supplies seem to be one of the major areas to play around with. Both are typically overlooked, and the power section in particular makes a huge difference to kit.
I recently had a chap knock up a new PSU for my DAC, really did make a big improvement.
Interesting note on the green pen thing is that Naim paint the insides of their CD mechanisms in matt green, which they claim helps. No idea if that's them jumping on the bandwagon or not.
Isolation and power supplies seem to be one of the major areas to play around with. Both are typically overlooked, and the power section in particular makes a huge difference to kit.
I recently had a chap knock up a new PSU for my DAC, really did make a big improvement.
Monstermunch said:
CD lasers are in the near infra-red part of the spectrum... something looks green under white light because it absorbs blue and red, reflecting the green... just as something looks blue because it absorbs red and green. I have no idea why green would help the music sound better, like i said CD laser wavelength is infra-red.
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Mpingo dots....
9designs2 said:It came out before copy protection. Was meant to stop stray light escaping from the edge of the disc..... Made a huge sound improvement,.... said so in a magazine !!!
I can't see how that could possibly make any difference to sound quality whatsoever. The information stored on a CD is purely digital (just a lot of 1's and 0's) the information is either "on" or "off". Stray light escaping from tray? The laser can either read the 1's and 0's or not... There is no middle ground.
While I am 100% certain a green tray or green pen won't effect sound quality there may be something in it with reagrds to reading reliability, but I really don't know enough about that.
At this particular stage in the audio chain every system is identical since every CD is identical.
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9designs2's post had more than a whiff of deep sarcasm there GordyR
Trying to piece together the physics that could lead to something like this, perhaps the laser reflecting back and bounced off enough surfaces might find its way back into the optics. Unlikely and almost certain to be handled by the (inaudible) error correction given you can put a 1cm hole in a CD and it will still play fine
As far as 1s and 0s being on and off, well, almost, but not quite. nothing is perfect like that, there are leading edges and rise times to take into account, even with the best pressings! Even with the set-in-stone CD standard clocking, I am willing to bet there is measurable jitter in the transport stages the laser bit) of cheaper readers
Trying to piece together the physics that could lead to something like this, perhaps the laser reflecting back and bounced off enough surfaces might find its way back into the optics. Unlikely and almost certain to be handled by the (inaudible) error correction given you can put a 1cm hole in a CD and it will still play fine
As far as 1s and 0s being on and off, well, almost, but not quite. nothing is perfect like that, there are leading edges and rise times to take into account, even with the best pressings! Even with the set-in-stone CD standard clocking, I am willing to bet there is measurable jitter in the transport stages the laser bit) of cheaper readers
A few thoughts on CD reading.
We assume that because CD makes a good storage medium for PCs, that it's inherently reliable and stores/retrieves 100% of data.
However, that's in a PC, which has a drive that can and does retry when necessary. So it is possible that on an CD player based drive that re-reading of disks doesn't happen, and that data really is lost/ignored. Maybe someone can pass comment on that?
With regard to error correction. Two things come to mind on that:
1. Error correction implies that a CD player must complete a calculation to recalculate the real value. By logical implication, any calculation, however simple requires time (even if it is VERY small). That may induce timing errors or jitter as it's commonly known as.
2. I've read that when a laser is struggling to read a disk because of dirt, dust, jam or whatever else someone smears on the disk, that the servo has to be powered. That power requirement can feed down to the power supply and potentially interfere with other output circuits, also resulting in increase jitter.
So things really aren't as straightforward as they seem.
What I can comment on from experience is that upgrading power supplies to both my CD transport and DAC, each made quite sizeable improvements to sound quality.
We assume that because CD makes a good storage medium for PCs, that it's inherently reliable and stores/retrieves 100% of data.
However, that's in a PC, which has a drive that can and does retry when necessary. So it is possible that on an CD player based drive that re-reading of disks doesn't happen, and that data really is lost/ignored. Maybe someone can pass comment on that?
With regard to error correction. Two things come to mind on that:
1. Error correction implies that a CD player must complete a calculation to recalculate the real value. By logical implication, any calculation, however simple requires time (even if it is VERY small). That may induce timing errors or jitter as it's commonly known as.
2. I've read that when a laser is struggling to read a disk because of dirt, dust, jam or whatever else someone smears on the disk, that the servo has to be powered. That power requirement can feed down to the power supply and potentially interfere with other output circuits, also resulting in increase jitter.
So things really aren't as straightforward as they seem.
What I can comment on from experience is that upgrading power supplies to both my CD transport and DAC, each made quite sizeable improvements to sound quality.
DRZ said:9designs2's post had more than a whiff of deep sarcasm there GordyR
Oh absolutely!
DRZ said:Trying to piece together the physics that could lead to something like this, perhaps the laser reflecting back and bounced off enough surfaces might find its way back into the optics. Unlikely and almost certain to be handled by the (inaudible) error correction given you can put a 1cm hole in a CD and it will still play fine
As far as 1s and 0s being on and off, well, almost, but not quite. nothing is perfect like that, there are leading edges and rise times to take into account, even with the best pressings! Even with the set-in-stone CD standard clocking, I am willing to bet there is measurable jitter in the transport stages the laser bit) of cheaper readers
Indeed but even so the data is read in bits is it not? Therefore with digital medium it is either read or it isn't. A CD drive itself doesn't turn the data in to analogue therefore that digital information or "bits" are the same everytime as long as the CD is being read 100% with no bits of mising data.
As far as I can see (and my reasoning could be wrong since I am no expert on this) assuming that a CD player is jitter free and working correctly and is reading 100% of those "bits" then the potential sound quality at this stage in the audio chain is a high as it possible can be and no "tweaks" could ever improve upon it since the data has now entered the audio system with the exactly same information that the mastering engineer ended up with when he downsampled to 16bit 44khz.
Anyway, I could be completely wrong with my assertions here. I am no electrical engineer, so please forgive me if I am indeed incorrect.
It's hard to explain my point here... But I hope you see what I am getting at.
I think Meridian use PC DVD ROM drives on their higher end players (G08 and it's predecessor ?) which in fact does re read data if there are read errors. I don't think this is common practice though. With a large enough data buffer there is plenty of time to re read the disk. A bit like buffer under run protection.
GordyR said:Oh absolutely!
Indeed but even so the data is read in bits is it not? Therefore with digital medium it is either read or it isn't. A CD drive itself doesn't turn the data in to analogue therefore that digital information or "bits" are the same everytime as long as the CD is being read 100% with no bits of mising data.
As far as I can see (and my reasoning could be wrong since I am no expert on this) assuming that a CD player is jitter free and working correctly and is reading 100% of those "bits" then the potential sound quality at this stage in the audio chain is a high as it possible can be and no "tweaks" could ever improve upon it since the data has now entered the audio system with the exactly same information that the mastering engineer ended up with when he downsampled to 16bit 44khz.
Anyway, I could be completely wrong with my assertions here. I am no electrical engineer, so please forgive me if I am indeed incorrect.
It's hard to explain my point here... But I hope you see what I am getting at.
Yeah GordyR your wrong !!!
To be honest I’m not an expert, and a lot of what I have read I can’t remember !! LOL
But the points DRZ and Mr_S are right, the readability of a disc has an effect on the sound. It’s not all “on and off”
The more difficult to read the more correction is need in the player which degrades the sound. This is why you often find high end players are rubbish at reading less than perfect discs…. To get the best sound the error correction is either turned off or right down……. I know I have a Unidisk !!!!
So I guess this where the green pen thing was heading. Improved disc readability, equals less correction, equals better sound…. It was a theory, but I never bought in to the “practice”
Some are now moving to the cheaper and more available PC DVD style drives to read discs, and then caching to memory as solution to the problem… Then all the jitter and issues are sorted in the buffer…..they claim.
So not all transports sound the same…..
9designs2 said:
I think everyone is misunderstanding what i'm saying. I'm not talking about jitters and error correction etc which will degrade sound quality. I understand perfectly that if a disk is dusty or dirty or whatever then the CD player needs to correct for that and that players will vary in that regard.
My point is that you can't improve the sound any further than the sound of the original digital information. If the player is reading every single "bit" of data in a song then the sound quality at that point in the chain will be as high as it possibly can be.
If that wasn't the case then a digital .wav file stored and played through a PC would have superior quality to a brand new CD played on the same PC. Now, if the CD player is low in quality then it can degrade the sound quality, but no player no matter how high the quality or technology used can improve upon the sound quality any more than a 100% successful read of the digital data. To do so would require the player to actually add digital information, which obviously they don't do.
I'm really struggling to get my point accross here as I don't know how best to explain myself with regards to this.
Basically what I'm saying is that assuming 100% of the digital data is being read off a CD (i.e no error correction needed) then the sound quality cannot be improved any further at that stage in the audio chain. You cannot read more than 100% of the data.
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Gordy,
I understand what you're saying, and you're 100% correct.
If a CD transport could give a 100% clean and full digital signal to it's DAC, then it would have done it's job.
In practice, nothing is ever perfect, and the best that can be done is minimise the issues.
I understand what you're saying, and you're 100% correct.
If a CD transport could give a 100% clean and full digital signal to it's DAC, then it would have done it's job.
In practice, nothing is ever perfect, and the best that can be done is minimise the issues.
GordyR said:I think everyone is misunderstanding what i'm saying. I'm not talking about jitters and error correction etc which will degrade sound quality. I understand perfectly that if a disk is dusty or dirty or whatever then the CD player needs to correct for that and that players will vary in that regard.
My point is that you can't improve the sound any further than the sound of the original digital information. If the player is reading every single "bit" of data in a song then the sound quality at that point in the chain will be as high as it possibly can be.
If that wasn't the case then a digital .wav file stored and played through a PC would have superior quality to a brand new CD played on the same PC. Now, if the CD player is low in quality then it can degrade the sound quality, but no player no matter how high the quality or technology used can improve upon the sound quality any more than a 100% successful read of the digital data. To do so would require the player to actually add digital information, which obviously they don't do.
I'm really struggling to get my point accross here as I don't know how best to explain myself with regards to this.
Basically what I'm saying is that assuming 100% of the digital data is being read off a CD (i.e no error correction needed) then the sound quality cannot be improved any further at that stage in the audio chain. You cannot read more than 100% of the data.
Spot on
Here's another treatment for the "Reading 1's and 0's" problem..... I offer no opinion, just thought it was worth a read
Auric Illuminator
http://www.audience-av.com/accessor.htm
Auric Illuminator
http://www.audience-av.com/accessor.htm