Computer based audio vs. dedicated CD transport?
Discussion
clonmult said:
paddyhasneeds said:
I have to admit I still can't get my head around the technical side of how a £20 CD/DVD Rom transport, as found in a PC, is sufficient to deal with critical file and program data, yet a transport in a high end audio CD player is better?
Basically shows that spending thousands on dedicated transports is a load of bo**ocks. They do NOT do a better job of pulling the bits of the disc.GnuBee said:
"I think the most misunderstood thing about CDs and playing and ripping them is that they are NOT a digital media.
There is no digital information on them, they are just an analogue series of grooves and peaks and troughs. Thus the production and playback quality of them will be dependant on the quality of the CD transport playing - or ripping them. I hasten to add that if you are looking at a system of less than £1000 these type of issues don't come into play. However, on my £25k system to literally get the best out of even the most minor issues do make the overall sound quite different."
I don't get this, sorry I really dont - the difference between a one and zero on the surface of the CD is indeed a physical thing but were not talking about vinyl here, were talking about a laser obtaining a 1 or 0 depending on the peak/trough.
Now there's now way you can convince me that some systems interpret these differently and that where a cheap system may see a 1 an expensive one sees a 0 or perhaps 1*
I don't doubt that your system sounds fabulous but I also don't doubt that at the level it closely matches your idea of a perfect system - it appears that audiophile level kit is very, very subjective and is often much more about finding a system that reproduces music the way the listener wishes to hear it rather than as the final word in absolute and faithful reproduction of the source.
A few issues here, and firstly, I quite agree that in Hi-Fi 'world' I do believe there is a lot of 'snake oil'. Indeed, there is also a law of dinishing returns where at a certain level spending an extra £100/£1000/£10,000 is not going to get you *that much* more performance.There is no digital information on them, they are just an analogue series of grooves and peaks and troughs. Thus the production and playback quality of them will be dependant on the quality of the CD transport playing - or ripping them. I hasten to add that if you are looking at a system of less than £1000 these type of issues don't come into play. However, on my £25k system to literally get the best out of even the most minor issues do make the overall sound quite different."
I don't get this, sorry I really dont - the difference between a one and zero on the surface of the CD is indeed a physical thing but were not talking about vinyl here, were talking about a laser obtaining a 1 or 0 depending on the peak/trough.
Now there's now way you can convince me that some systems interpret these differently and that where a cheap system may see a 1 an expensive one sees a 0 or perhaps 1*
I don't doubt that your system sounds fabulous but I also don't doubt that at the level it closely matches your idea of a perfect system - it appears that audiophile level kit is very, very subjective and is often much more about finding a system that reproduces music the way the listener wishes to hear it rather than as the final word in absolute and faithful reproduction of the source.
The other issue is that when these differences become so tiny, it *is* difficult to notice them and probably needs pretty trained ears - which is the point. In my professional work when I have mixed tracks I have often received feedback from those with 'a little knowledge' who would like to impress to others they are the new George Martin. I get some quite random and meaningless changes to be made such as 'lets make the bass more chocolately'.
If you are aware of the legend of 'The Emperor's New Clothes', you can guess what happens next... I tell them I am not so sure, but I will have a go...
Of course, when they get the now master they can notice the difference *straight away* and its now perfect! (of course only after their input). Not once has someone told me that I have in fact supplied them with an indentical mix they had in the first place...
There is also a lot of this in the Hi-Fi world. That said, as mentioned in my earlier thread I am a sceptic in most things and have not made any changes to my system without literally hours of testing back and forth. Indeed I have mentioned above, I am not afraid to say that a transport system which has essentially cost me a tenner has matched my £3000 transport!
With regard to the differences between CD transports, there are certainly differences in qualities between them. I have heard that with my own ears. What you have to remember is that for the DAC to do its job to the best of its abilty it needs to be fed the 1's and 0's not just accurately, but consistantly to miniscule timing tolerances. Even if this is out a miniscule amount this will start to degrade the performance of a DAC or the DAC wont be able to work at all.
If you think about the amount of digits which are put into a DAC in a single second, to say that all CD transports are the same is also saying that each transport has identical performance. As a CD transport is in effect a mechanical device, there are variations between makes and models. Each one will be able to dynamically adjust the spin speed of the CD and the digital reading to feed that DAC in a more accurate or less accurate way. Whilt the reading of the 1's and 0's may only be a small part - and indeed if a few of these are wrong the CD will still play - the timing of the 1's and 0's is the real issue.
That said, I do think that with technology out *now* the issue of a good transport or not is nullified as I have discovered a solid state system is just as good or better. Similarly, there are DACs out there which will essentially put the 1's and 0's in a buffer and retime these before they hit the DAC. Personally I think it is better as it is removing the mechanical variables that made the difference between the £50 transport and the £3000 transport that different.
I think what you are talking about Justin is the difference between playback of a CD on a cheap computer CD ROM and on a hifi CD player.
I'd be the first to agree that there could be a massive difference in that case.
However in terms of taking the data from a CD and reproducing it via a media player, it is possible to get just as good results ripping the data from a £20 CD ROM as it is from playing the same disc in a £2000 CD player as the data is read exactly the same, bit for bit. Throw that data through a high-end DAC etc and you end up with comparable results as Plotloss found out with the Transporter.
I'd be the first to agree that there could be a massive difference in that case.
However in terms of taking the data from a CD and reproducing it via a media player, it is possible to get just as good results ripping the data from a £20 CD ROM as it is from playing the same disc in a £2000 CD player as the data is read exactly the same, bit for bit. Throw that data through a high-end DAC etc and you end up with comparable results as Plotloss found out with the Transporter.
JustinP1 said:
I think the most misunderstood thing about CDs and playing and ripping them is that they are NOT a digital media.
There is no digital information on them, they are just an analogue series of grooves and peaks and troughs. Thus the production and playback quality of them will be dependant on the quality of the CD transport playing - or ripping them.
Not true. A CD encodes analogue audio information using a digital encoding scheme with error correction. They are not records-played-by-lasers, which is how I understand your statement.There is no digital information on them, they are just an analogue series of grooves and peaks and troughs. Thus the production and playback quality of them will be dependant on the quality of the CD transport playing - or ripping them.
CD rippers can extract correct (i.e. as-encoded) audio information from CDs on the cheapest of CD drives.
(I assume "transport" is a way of saying "CD drive" that makes one feel better about paying over the odds)
commander said said:
CD rippers can extract correct (i.e. as-encoded) audio information from CDs on the cheapest of CD drives.
But often this is done by oversampling (certainly in the case of EAC) hence the variable time in ripping CDs with EAC. Poor condition CDs can take tens of minutes.Meridian use the same technique in their high end CD player (Meridian 800), by using a ROM drive, they can effectively oversample each section in real time and make better judgements as to the required error correction.
davidy
CDs most certainly do contain digital data. The fact that the representation on the physical disk is 'analogue' is only due to the fact that there has to be a change in height, no matter how short between the various bits.
Digital electronics are similar - the difference between a 1 and a 0 is determined by different voltages, be it +ve and -Ve or between two +ve levels. These are still analogue signals, in that if you put them on an oscilloscope you will most likely not get a perfect square wave. There may well be fluctuations in the level and overshoot when changing between levels, however that is not important. The essential fact is that there are two distinct states that can be discriminated. As long as these can be sufficiently determined, the signal will arrive perfectly at the other end. That is why a digital interconnect will make not have difference on the quality of the sound.
Cheap CD drives for computers is that they can accurately reproduce data - the computer would not be able to use it otherwise. The advantage a computer has over even an expensive audio cd player is that it is not restricted by time to acheive an accurate data stream.
Digital electronics are similar - the difference between a 1 and a 0 is determined by different voltages, be it +ve and -Ve or between two +ve levels. These are still analogue signals, in that if you put them on an oscilloscope you will most likely not get a perfect square wave. There may well be fluctuations in the level and overshoot when changing between levels, however that is not important. The essential fact is that there are two distinct states that can be discriminated. As long as these can be sufficiently determined, the signal will arrive perfectly at the other end. That is why a digital interconnect will make not have difference on the quality of the sound.
Cheap CD drives for computers is that they can accurately reproduce data - the computer would not be able to use it otherwise. The advantage a computer has over even an expensive audio cd player is that it is not restricted by time to acheive an accurate data stream.
I use a system exactly described in this thread.
I rip CDs using EAC and store them to my PC (read: media server I suppose). This then plays out via ethernet to my SqueezeBox which sits over by the hifi. I then connect via digital coax to my DAC1 which feeds into my Naim pre-amp.
I also have a Naim DVD5 which I use for DVDs (obviously) but it also makes an excellent job on CDs too.
I've tried playing tracks directly between the two, switching between PC based playback and direct from the disc playback in realtime and it's virtually impossible to split them. I'd say the DVD playback has slightly better imaging, but it's sooooo marginal. Given the convenience of PC based playback it's a complete no brainer.
I wish the HIFI mags would get on and write some informed articles on these. It took them long enough to realise that 5.1 could sound like true audiophile playback (I have a Naim AV2 for decoding that, and it's wonderful).
What I haven't got close to yet is DVD playback off a PC. Playing back through my media PC is OK via HDMI, but not really in the same league as the Naim DVD5. Not sure why that is, seems to drop frames etc so may need to move to a ebtter video card. But with audio it's PC all the way for me.
I rip CDs using EAC and store them to my PC (read: media server I suppose). This then plays out via ethernet to my SqueezeBox which sits over by the hifi. I then connect via digital coax to my DAC1 which feeds into my Naim pre-amp.
I also have a Naim DVD5 which I use for DVDs (obviously) but it also makes an excellent job on CDs too.
I've tried playing tracks directly between the two, switching between PC based playback and direct from the disc playback in realtime and it's virtually impossible to split them. I'd say the DVD playback has slightly better imaging, but it's sooooo marginal. Given the convenience of PC based playback it's a complete no brainer.
I wish the HIFI mags would get on and write some informed articles on these. It took them long enough to realise that 5.1 could sound like true audiophile playback (I have a Naim AV2 for decoding that, and it's wonderful).
What I haven't got close to yet is DVD playback off a PC. Playing back through my media PC is OK via HDMI, but not really in the same league as the Naim DVD5. Not sure why that is, seems to drop frames etc so may need to move to a ebtter video card. But with audio it's PC all the way for me.
CommanderJameson said:
JustinP1 said:
I think the most misunderstood thing about CDs and playing and ripping them is that they are NOT a digital media.
There is no digital information on them, they are just an analogue series of grooves and peaks and troughs. Thus the production and playback quality of them will be dependant on the quality of the CD transport playing - or ripping them.
Not true. A CD encodes analogue audio information using a digital encoding scheme with error correction. They are not records-played-by-lasers, which is how I understand your statement.There is no digital information on them, they are just an analogue series of grooves and peaks and troughs. Thus the production and playback quality of them will be dependant on the quality of the CD transport playing - or ripping them.
CD rippers can extract correct (i.e. as-encoded) audio information from CDs on the cheapest of CD drives.
(I assume "transport" is a way of saying "CD drive" that makes one feel better about paying over the odds)
Each of these processes are not perfect, even ripping. Indeed some ripping softwares will rip the same data more than once and compare 'rips' for errors.
There can also be inconsistancies with the disc itself. It goes without saying that a dirty or scratched disk is not the best. However, error correction minimises the very audible 'skips' through unreadable sections of the disc, and the CD drive can actively slow down or re-read certain sections. A CD player does not have this luxury and has to put out data 'on the fly' pretty much as is - or with the best error correction it can muster in the timeframe.
As I have mentioned in my previous post where I spent a lot of time testing - if you can make a good, accruate rip of a CD with the right gear you can match the performance of even a theoretically perfect CD transport for a fraction of the cost.
The Dude said:
I think what you are talking about Justin is the difference between playback of a CD on a cheap computer CD ROM and on a hifi CD player.
I'd be the first to agree that there could be a massive difference in that case.
However in terms of taking the data from a CD and reproducing it via a media player, it is possible to get just as good results ripping the data from a £20 CD ROM as it is from playing the same disc in a £2000 CD player as the data is read exactly the same, bit for bit. Throw that data through a high-end DAC etc and you end up with comparable results as Plotloss found out with the Transporter.
I think you have pretty much summed up my testing in my post above yours where I was trying to sceintifically answer the OP's question. I'd be the first to agree that there could be a massive difference in that case.
However in terms of taking the data from a CD and reproducing it via a media player, it is possible to get just as good results ripping the data from a £20 CD ROM as it is from playing the same disc in a £2000 CD player as the data is read exactly the same, bit for bit. Throw that data through a high-end DAC etc and you end up with comparable results as Plotloss found out with the Transporter.
If you can have all the time in the world to rip the original CD to copy the data then you already have what the CD transport is trying to achieve and send out each time mechanically.
As far as I can see once you have the raw data, the next issue is getting the clocking of that matched to the DAC. However, as I mentioned the Apogee DAC in my unit and others such as the Chord DAC64 buffer and retime the digital data anyway.
JustinP1 said:
CommanderJameson said:
JustinP1 said:
I think the most misunderstood thing about CDs and playing and ripping them is that they are NOT a digital media.
There is no digital information on them, they are just an analogue series of grooves and peaks and troughs. Thus the production and playback quality of them will be dependant on the quality of the CD transport playing - or ripping them.
Not true. A CD encodes analogue audio information using a digital encoding scheme with error correction. They are not records-played-by-lasers, which is how I understand your statement.There is no digital information on them, they are just an analogue series of grooves and peaks and troughs. Thus the production and playback quality of them will be dependant on the quality of the CD transport playing - or ripping them.
CD rippers can extract correct (i.e. as-encoded) audio information from CDs on the cheapest of CD drives.
(I assume "transport" is a way of saying "CD drive" that makes one feel better about paying over the odds)
If it was not a digital medium, you wouldn't need a DAC.
CommanderJameson said:
JustinP1 said:
CommanderJameson said:
JustinP1 said:
I think the most misunderstood thing about CDs and playing and ripping them is that they are NOT a digital media.
There is no digital information on them, they are just an analogue series of grooves and peaks and troughs. Thus the production and playback quality of them will be dependant on the quality of the CD transport playing - or ripping them.
Not true. A CD encodes analogue audio information using a digital encoding scheme with error correction. They are not records-played-by-lasers, which is how I understand your statement.There is no digital information on them, they are just an analogue series of grooves and peaks and troughs. Thus the production and playback quality of them will be dependant on the quality of the CD transport playing - or ripping them.
CD rippers can extract correct (i.e. as-encoded) audio information from CDs on the cheapest of CD drives.
(I assume "transport" is a way of saying "CD drive" that makes one feel better about paying over the odds)
If it was not a digital medium, you wouldn't need a DAC.
Its the mechanical process not what it holds which is the difference. The digital signal is encoded to the peaks and troughs onto the CD. This is done either through pressing or with a CDR a laser printing peaks and troughs into a dye. In playback the CD is then read mechanically with a laser and the peaks and troughs are encoded back to the digital signal. *Then* the signal is converted by the DAC.
For those still interested in the thread I thought I would post an update.
I did some research into the CD Transport and CD-ROM differences and found that technically there are fundamental differences between the way they read audio CDs and that audio CDs are NOT a simple stream of ones and noughts.
CD Audio discs are actually not one but three discrete streams of data. When 'playing' a disc the transport chooses which of the first two 'grooves' of data to use and then 'in doubt' will use the third 'error correction' track. For this reason, it is entirely possible and indeed almost a certainty that different CD transports will output a slightly different data stream, indeed two outputs of the same disc can be different even on the same player!
Apparantly most of this variation is down to the quality and the fundamental properties of the CD itself. Mastering engineers can even tell the difference between the sound of the same disk produced in different plants and even the same disk produced in the same factory at different times.
As explained earlier in the thread this is down to the 'mechanical' nature of the technology. On many discs the pressing of the 'grooves' themselves are variable and also the optical qualities and integrity of the plastic itself change how easily the disc is read. Interestingly damage to the 'label' side of the disc is most damaging and photos of the tracks at a microscopic level shows the grooves completely destroyed.
In a 'data' disc there are more levels of redundancy and error correction which mean that important data is usually maintained. Interestingly a CD-ROM also does not read an audio disc in the same way, instead of forming a single stream, it reads in short sectors and then stitches the sectors together.
However... as I thought earlier, a 'perfect' rip, or at least one is as good as can be possible, *will* hold the same data as the feed from a good transport - or at least close enough. Indeed, it is my personal opinion that the integrity of the data should be more consistant when comparing the rip to a CD transport due to the fact that a source of mechanical variation has been removed.
As such, and thanks to the OP making me seriously test, I am now the proud owner of a Mac Mini! I have added a 500Gb external drive to it and as we speak I am ripping my entire collection to it.
It comes pre-loaded with a nifty GUI called Front Row which not only shows the album artwork (automatically downloaded from the net) and correctly shows the album name and track names. So, from the comfort of my sofa I will be able to browse my whole collection whilst viewing my TV and jumping seamlessly between tracks instantly whilst choosing them with the special remote control included with the Mac.
Brilliant. Purchase of the year.
I did some research into the CD Transport and CD-ROM differences and found that technically there are fundamental differences between the way they read audio CDs and that audio CDs are NOT a simple stream of ones and noughts.
CD Audio discs are actually not one but three discrete streams of data. When 'playing' a disc the transport chooses which of the first two 'grooves' of data to use and then 'in doubt' will use the third 'error correction' track. For this reason, it is entirely possible and indeed almost a certainty that different CD transports will output a slightly different data stream, indeed two outputs of the same disc can be different even on the same player!
Apparantly most of this variation is down to the quality and the fundamental properties of the CD itself. Mastering engineers can even tell the difference between the sound of the same disk produced in different plants and even the same disk produced in the same factory at different times.
As explained earlier in the thread this is down to the 'mechanical' nature of the technology. On many discs the pressing of the 'grooves' themselves are variable and also the optical qualities and integrity of the plastic itself change how easily the disc is read. Interestingly damage to the 'label' side of the disc is most damaging and photos of the tracks at a microscopic level shows the grooves completely destroyed.
In a 'data' disc there are more levels of redundancy and error correction which mean that important data is usually maintained. Interestingly a CD-ROM also does not read an audio disc in the same way, instead of forming a single stream, it reads in short sectors and then stitches the sectors together.
However... as I thought earlier, a 'perfect' rip, or at least one is as good as can be possible, *will* hold the same data as the feed from a good transport - or at least close enough. Indeed, it is my personal opinion that the integrity of the data should be more consistant when comparing the rip to a CD transport due to the fact that a source of mechanical variation has been removed.
As such, and thanks to the OP making me seriously test, I am now the proud owner of a Mac Mini! I have added a 500Gb external drive to it and as we speak I am ripping my entire collection to it.
It comes pre-loaded with a nifty GUI called Front Row which not only shows the album artwork (automatically downloaded from the net) and correctly shows the album name and track names. So, from the comfort of my sofa I will be able to browse my whole collection whilst viewing my TV and jumping seamlessly between tracks instantly whilst choosing them with the special remote control included with the Mac.
Brilliant. Purchase of the year.
My computer system sounds better than anyone elses, IMO, is cheaper than many, and the reason is based both on listening and science.
First - rip CDs to WAV format with Grip (cdparanoia etc) to get a perfect CD image (tracks).
Second - these CD tracks will be clipped - because that is how they are made nowadays. So you need iTunes, and this free de-clipping iTunes server. This doesn't 'fudge' or 'smooth' the waveforms - it recreates the missing sections from the other channel and nearby unclipped portions.
Third - Get a Mac + Airport Express to play the (now declipped/restored) tunes.
Fourth - get an optical lead and a Behringer Ultramatch to re-time the signal (removing jitter) and up convert to 88.2kHz (digital). De-jitter and up conversion.
Fifth - Get another Ultramatch or an Ultracurve to convert the 88.2kHz digital to analog (a much better conversion than 44.1kHz for the treble). D to A.
Six - Listen, and realise how much better it sounds than the most expensive Naim CD player made.
QED.
First - rip CDs to WAV format with Grip (cdparanoia etc) to get a perfect CD image (tracks).
Second - these CD tracks will be clipped - because that is how they are made nowadays. So you need iTunes, and this free de-clipping iTunes server. This doesn't 'fudge' or 'smooth' the waveforms - it recreates the missing sections from the other channel and nearby unclipped portions.
Third - Get a Mac + Airport Express to play the (now declipped/restored) tunes.
Fourth - get an optical lead and a Behringer Ultramatch to re-time the signal (removing jitter) and up convert to 88.2kHz (digital). De-jitter and up conversion.
Fifth - Get another Ultramatch or an Ultracurve to convert the 88.2kHz digital to analog (a much better conversion than 44.1kHz for the treble). D to A.
Six - Listen, and realise how much better it sounds than the most expensive Naim CD player made.
QED.
Meridian 800 Uses a Cheap DVD drive. It doesn't play CD well enough at it's price to be considered a good CD Player. DVD-Audio is very good though.
CD mechanism's are cheap and Powerful these days no matter who makes them. However most reviewers reckon the old "swing arm" Philips unit's are better than the newer Parallel tracking Sleds used on the new Units. Even better are CD units that are isolated and or have mass in the unit to stop the Error correction cutting in.
DAC Units that either connect the timing Clocks or have a correction method have been acknowledged as being better since the mid Nineties. DPA introduced them on the PDM1 DAC.
CD mechanism's are cheap and Powerful these days no matter who makes them. However most reviewers reckon the old "swing arm" Philips unit's are better than the newer Parallel tracking Sleds used on the new Units. Even better are CD units that are isolated and or have mass in the unit to stop the Error correction cutting in.
DAC Units that either connect the timing Clocks or have a correction method have been acknowledged as being better since the mid Nineties. DPA introduced them on the PDM1 DAC.
telecat said:
However most reviewers reckon the old "swing arm" Philips unit's are better than the newer Parallel tracking Sleds used on the new Units.
However most reviewers don't know their arse from their elbow and haven't even thought about the problem.1) The sleds have magnetically adjusting lenses - the sled just gets a rough positioning.
2) The reviewers are not measuring error rates - the only way of testing them.
3) A CD player plays at 1x speed and _has_ to get the data perfectly.
4) A Computer drive can read bit-perfect data at 48x speed, and CDParanoia steps down the speed and retries many times to be sure it got the exact digital image. A regular CD player (however much it costs) simply cannot compete with this.
Most reviewers don't even know their CD source is clipped - basic audio 101 - don't clip the signal - is therefore ignored in favour of some spurious comments about the resulting hash that appears from the system they are listening to.
Hype and advertising revenue is great, but will never beat physics or mathematics
Globulator said:
telecat said:
However most reviewers reckon the old "swing arm" Philips unit's are better than the newer Parallel tracking Sleds used on the new Units.
However most reviewers don't know their arse from their elbow and haven't even thought about the problem.1) The sleds have magnetically adjusting lenses - the sled just gets a rough positioning.
2) The reviewers are not measuring error rates - the only way of testing them.
3) A CD player plays at 1x speed and _has_ to get the data perfectly.
4) A Computer drive can read bit-perfect data at 48x speed, and CDParanoia steps down the speed and retries many times to be sure it got the exact digital image. A regular CD player (however much it costs) simply cannot compete with this.
Most reviewers don't even know their CD source is clipped - basic audio 101 - don't clip the signal - is therefore ignored in favour of some spurious comments about the resulting hash that appears from the system they are listening to.
Hype and advertising revenue is great, but will never beat physics or mathematics
2. Reviewers gave up error correction monitoring when they discovered that nearly all CD units corrected at the same rate. (Excepting custom built units).
3. As far as I am aware any Computer drive used uses its speed to re-read any area it has a problem with.
4. Believe that and you'll believe anything. Nothing is perfect modern drive "guess" at higher speed.
telecat said:
Globulator said:
telecat said:
However most reviewers reckon the old "swing arm" Philips unit's are better than the newer Parallel tracking Sleds used on the new Units.
However most reviewers don't know their arse from their elbow and haven't even thought about the problem.1) The sleds have magnetically adjusting lenses - the sled just gets a rough positioning.
2) The reviewers are not measuring error rates - the only way of testing them.
3) A CD player plays at 1x speed and _has_ to get the data perfectly.
4) A Computer drive can read bit-perfect data at 48x speed, and CDParanoia steps down the speed and retries many times to be sure it got the exact digital image. A regular CD player (however much it costs) simply cannot compete with this.
Most reviewers don't even know their CD source is clipped - basic audio 101 - don't clip the signal - is therefore ignored in favour of some spurious comments about the resulting hash that appears from the system they are listening to.
Hype and advertising revenue is great, but will never beat physics or mathematics
2. Reviewers gave up error correction monitoring when they discovered that nearly all CD units corrected at the same rate. (Excepting custom built units).
3. As far as I am aware any Computer drive used uses its speed to re-read any area it has a problem with.
4. Believe that and you'll believe anything. Nothing is perfect modern drive "guess" at higher speed.
1 - Exactly, the lens compensates for any stepping (like I said)
2 - Not sure we're talking about the same thing
3 - Exactly - audio CD players do not and can not (i.e if it's wrong it will stay wrong)
4 - Believe what? That a 48x reader can read at 48x? Nothing amazing there.
Digital CD readers do not 'guess', they check and retry. Slower if required. So also can the software - i.e. CDParanoia, audio CD players can and do not do this.
There is no argument here as far as I can see, I'm just pointing out that sleds have been developed by the computing industry to be significantly better than old audio swing arms. I'm sure audio sleds are still rubbish - but there again I don't rate any audio CD player because:
1) They are single speed and errors will remain and be heard as errors
2) Clipping makes them non hi-fi anyway
Globulator said:
telecat said:
Globulator said:
telecat said:
However most reviewers reckon the old "swing arm" Philips unit's are better than the newer Parallel tracking Sleds used on the new Units.
However most reviewers don't know their arse from their elbow and haven't even thought about the problem.1) The sleds have magnetically adjusting lenses - the sled just gets a rough positioning.
2) The reviewers are not measuring error rates - the only way of testing them.
3) A CD player plays at 1x speed and _has_ to get the data perfectly.
4) A Computer drive can read bit-perfect data at 48x speed, and CDParanoia steps down the speed and retries many times to be sure it got the exact digital image. A regular CD player (however much it costs) simply cannot compete with this.
Most reviewers don't even know their CD source is clipped - basic audio 101 - don't clip the signal - is therefore ignored in favour of some spurious comments about the resulting hash that appears from the system they are listening to.
Hype and advertising revenue is great, but will never beat physics or mathematics
2. Reviewers gave up error correction monitoring when they discovered that nearly all CD units corrected at the same rate. (Excepting custom built units).
3. As far as I am aware any Computer drive used uses its speed to re-read any area it has a problem with.
4. Believe that and you'll believe anything. Nothing is perfect modern drive "guess" at higher speed.
1 - Exactly, the lens compensates for any stepping (like I said)
2 - Not sure we're talking about the same thing
3 - Exactly - audio CD players do not and can not (i.e if it's wrong it will stay wrong)
4 - Believe what? That a 48x reader can read at 48x? Nothing amazing there.
Digital CD readers do not 'guess', they check and retry. Slower if required. So also can the software - i.e. CDParanoia, audio CD players can and do not do this.
There is no argument here as far as I can see, I'm just pointing out that sleds have been developed by the computing industry to be significantly better than old audio swing arms. I'm sure audio sleds are still rubbish - but there again I don't rate any audio CD player because:
1) They are single speed and errors will remain and be heard as errors
2) Clipping makes them non hi-fi anyway
As for 4 CD units read at a Maximum speed of 48X and may or may not get up to that speed. Positioning of data on the disc will slow the actual speed as will error correction. When it cannot verify the read data the unit will make a best guess which the error correction will test for accuracy. The result will be 100% accurate. The reading will not be.
As for "clipping" all Audio has clipping built in. It is dependant on the system used as to how this is heard. CD as originally produced has "hard" clipping where the signal is shut off at 44.1Khz. Oversampling and increasing the number of steps by increasing the number of "taps" on the digital filter produces a "softer" Clip.
Clipping is not just limited to Digital Audio though. Vinyl records are "clipped" because the Microgrooves cannot produce the full audible range. Compact cassette and smaller Tape was clipped due to the width of the tape. Frequency highs and lows could not be accomidated. Most amps "clip" the highest or lowest frequencies becuase of circuit or power limitations. Dismissing any product because it "clips" is pretty short sighted
This has to be the Ultimate Media Server. Not sure I'd fork out the Price though. Last I heard it was over £20k
Chord Media Server
Chord Media Server
telecat said:
As for 4 CD units read at a Maximum speed of 48X and may or may not get up to that speed. Positioning of data on the disc will slow the actual speed as will error correction. When it cannot verify the read data the unit will make a best guess which the error correction will test for accuracy. The result will be 100% accurate. The reading will not be.
Sorry I think my post must have been confusing.Instead of 'may', I'd like to change to 'are capable of under optimum conditions'.
telecat said:
As for "clipping" all Audio has clipping built in. It is dependant on the system used as to how this is heard. CD as originally produced has "hard" clipping where the signal is shut off at 44.1Khz. Oversampling and increasing the number of steps by increasing the number of "taps" on the digital filter produces a "softer" Clip.
Maybe a language thing? I'm not talking about bandwidth - everything has a bandwidth limit, even live music.telecat said:
Clipping is not just limited to Digital Audio though. Vinyl records are "clipped" because the Microgrooves cannot produce the full audible range. Compact cassette and smaller Tape was clipped due to the width of the tape. Frequency highs and lows could not be accomidated. Most amps "clip" the highest or lowest frequencies becuase of circuit or power limitations. Dismissing any product because it "clips" is pretty short sighted
I'm talking about clipping. Like this:
Obviously that's a bad one, but you'd be surprised - pretty much ALL modern pop is seriously clipped. Read my first post - I use an special iTunes server with declipping to fix this as best it can be.
More information about clipping
Gassing Station | Computers, Gadgets & Stuff | Top of Page | What's New | My Stuff