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CD transports and resonance
"Stewart Pinkerton" wrote in message ... On 06 Nov 2004 11:27:16 GMT, ohawker (Andy Evans) wrote: I have no wish to 'endow' (DP) anything. I'm reporting less distortion in highly modulated passages when a transport is damped. No, you're reporting that you *think* something is happening. You have as yet shown no indication that anything *real* is occuring. -- If I were Andy I'd be feeling like someone asked to prove, for ever, evidence of something that doesn't exist in the empirical world. Andy can't prove what he hears, and I'm inclined to think he (of all people) is aware of placebo-type effects. Why can't you turn this round - instead of asking him to prove it, you disprove it. Simple hypothesis - test it and see what happens. I suspect that behind your rather abrupt manner and bluster is a charitable soul trying to dissuade people from throwing time and money at what you see to be a pointless grail. I can't prove it though ;-). Rob |
CD transports and resonance
"Ian Molton" wrote in message ... Andy Evans wrote: Apart from the fact that I can hear it. There's no assurance that you have any technical knowledge that can explain it. I don't mind the fact that you can't explain it - our knowledge always has limitations. Your ear is a transducer - pressure to electrical impulses. we have mics available that can hear stuff humans cant (demonstrably - animals can hear the difference in the recordings where humans cant) therefore the tool to measure your claimed effect is available. Hi - have you got a link? either prove it or **** off. Thanks Rob |
CD transports and resonance
On Sat, 6 Nov 2004 19:42:58 -0000, "Rob"
wrote: "Stewart Pinkerton" wrote in message .. . On 06 Nov 2004 11:27:16 GMT, ohawker (Andy Evans) wrote: I have no wish to 'endow' (DP) anything. I'm reporting less distortion in highly modulated passages when a transport is damped. No, you're reporting that you *think* something is happening. You have as yet shown no indication that anything *real* is occuring. -- If I were Andy I'd be feeling like someone asked to prove, for ever, evidence of something that doesn't exist in the empirical world. Andy can't prove what he hears, and I'm inclined to think he (of all people) is aware of placebo-type effects. Why can't you turn this round - instead of asking him to prove it, you disprove it. Simple hypothesis - test it and see what happens. You haven't really thought this one through, have you. If somebody says there is no difference, then in any test all they have to say is "I can't hear a difference". That applies whether the difference exists or not. If somebody claims to hear a difference, they can prove it conclusively by identifying by sound alone - job done. Andy surprises me rather with his claims because he is fairly uniquely positioned in his psychological training to understand the reasoning and processes, yet chooses to ignore all his training and experience. I know that it is not nice to have your row of soldiers knocked down, but the experience can be both illuminating and cathartic. Having knocked them down, of course, you can then move on to something more productive. I suspect that behind your rather abrupt manner and bluster is a charitable soul trying to dissuade people from throwing time and money at what you see to be a pointless grail. I can't prove it though ;-). Rob I think you are right that many of us here do genuinely want people to listen with their ears and not go blowing valuable time and money on fruitless pursuits. Of course there is the point that the chase itself can be fun - but it is much more fun when yo know that there is some chance of there actually being a prize at the end. d Pearce Consulting http://www.pearce.uk.com |
CD transports and resonance
In article ,
Rob wrote: Andy can't prove what he hears, and I'm inclined to think he (of all people) is aware of placebo-type effects. Yet is continually offering up for comments things he can 'hear' that others wouldn't. -- *Why don't sheep shrink when it rains? Dave Plowman London SW To e-mail, change noise into sound. |
CD transports and resonance
I have no idea why, btw, but I'd be
curious if I could be bothered. Hello Rob - you summed up the situation quite neatly. Like you I have no idea why, and as you can see I have had no explanation. I put some time into this because, like you, I was curious and in my case I had some mechs lying about. New CD transports aren't exactly chump change, so it makes sense to start with what one has. Andy === Andy Evans === Visit our Website:- http://www.artsandmedia.com Audio, music and health pages and interesting links. |
CD transports and resonance
In article ,
Rob wrote: The assumption - and I think it's not unreasonable - is that stabilising a cd mechanism brings audible benefits. It would do if a record player. They can suffer from all sorts of vibration influenced effects. But a CD player is surprisingly digital. Assuming that digital signal can still be read it will work normally. If it is subjected to severe vibration it will stop - or at least produce some alarming noises. Nothing really in between. -- *How much deeper would the oceans be without sponges? * Dave Plowman London SW To e-mail, change noise into sound. |
CD transports and resonance
"Don Pearce" wrote in message ... On Sat, 6 Nov 2004 19:42:58 -0000, "Rob" wrote: "Stewart Pinkerton" wrote in message . .. On 06 Nov 2004 11:27:16 GMT, ohawker (Andy Evans) wrote: I have no wish to 'endow' (DP) anything. I'm reporting less distortion in highly modulated passages when a transport is damped. No, you're reporting that you *think* something is happening. You have as yet shown no indication that anything *real* is occuring. -- If I were Andy I'd be feeling like someone asked to prove, for ever, evidence of something that doesn't exist in the empirical world. Andy can't prove what he hears, and I'm inclined to think he (of all people) is aware of placebo-type effects. Why can't you turn this round - instead of asking him to prove it, you disprove it. Simple hypothesis - test it and see what happens. You haven't really thought this one through, have you. If somebody says there is no difference, then in any test all they have to say is "I can't hear a difference". That applies whether the difference exists or not. If somebody claims to hear a difference, they can prove it conclusively by identifying by sound alone - job done. :-). Complete and utter nonsense. The proper test is antithesis - look it up. Andy surprises me rather with his claims because he is fairly uniquely positioned in his psychological training to understand the reasoning and processes, yet chooses to ignore all his training and experience. Do you have any evidence of this? I know that it is not nice to have your row of soldiers knocked down, but the experience can be both illuminating and cathartic. Having knocked them down, of course, you can then move on to something more productive. I really don't think this is what Andy is doing - I see it as a simple test/pastime. I wouldn't presume to judge a person's productivity on the basis of this little exchange. I suspect that behind your rather abrupt manner and bluster is a charitable soul trying to dissuade people from throwing time and money at what you see to be a pointless grail. I can't prove it though ;-). Rob I think you are right that many of us here do genuinely want people to listen with their ears and not go blowing valuable time and money on fruitless pursuits. Of course there is the point that the chase itself can be fun - but it is much more fun when yo know that there is some chance of there actually being a prize at the end. There is a chance - that is, er, the point. It may be slim but I find an inquiring mind fascinating. How many massive breakthroughs to our understanding of the physical world have been made by people who were told 'Nope, it's impossible'. Challenge hegemony. Rob |
CD transports and resonance
Andy surprises me rather with his claims because he is fairly uniquely positioned in his psychological training to understand the reasoning and processes Hello Don! I'm not making claims (I've never said anyone else would be able to replicate this), as Rob said I'm making an observation. Now, if you have read your Freud you will know that what distinguished his work was that he didn't simply dismiss his personal observations - he looked for solutions which fitted his observations (a good example is his dream analysis after being turned down for an important post in his home town). Now, I have made an observation which I consider to be worth pursuing, and one which as we all know is paradoxical in binary terms. I've stated that I have no explanation for what I hear, that I do hear it, that I can't measure it because I have neither the equipment nor the knowledge. I then said "if others want to try this it's fairly cheap and simple". I asked if anyone has empirical knowledge of this from their own experience, and the answer so far is no. What I have received is opinions to the effect that if those giving such opinions were in my home listening to my equipment they would hear nothing. Now, since I can say with some confidence that nobody is in my home and in a position to ratify their opinions, it needs neither science nor psychology to conclude that they cannot personally comment on the sound of my equipment. Rob, for one, seems to understand this perfectly well. === Andy Evans === Visit our Website:- http://www.artsandmedia.com Audio, music and health pages and interesting links. |
CD transports and resonance
On 06 Nov 2004 20:31:29 GMT, ohawker (Andy
Evans) wrote: Andy surprises me rather with his claims because he is fairly uniquely positioned in his psychological training to understand the reasoning and processes Hello Don! I'm not making claims (I've never said anyone else would be able to replicate this), as Rob said I'm making an observation. Now, if you have read your Freud you will know that what distinguished his work was that he didn't simply dismiss his personal observations - he looked for solutions which fitted his observations (a good example is his dream analysis after being turned down for an important post in his home town). Now, I have made an observation which I consider to be worth pursuing, and one which as we all know is paradoxical in binary terms. I've stated that I have no explanation for what I hear, that I do hear it, that I can't measure it because I have neither the equipment nor the knowledge. I then said "if others want to try this it's fairly cheap and simple". I asked if anyone has empirical knowledge of this from their own experience, and the answer so far is no. What I have received is opinions to the effect that if those giving such opinions were in my home listening to my equipment they would hear nothing. Now, since I can say with some confidence that nobody is in my home and in a position to ratify their opinions, it needs neither science nor psychology to conclude that they cannot personally comment on the sound of my equipment. Rob, for one, seems to understand this perfectly well. === Andy Evans === Visit our Website:- http://www.artsandmedia.com Audio, music and health pages and interesting links. I know you have made observations - but of course once you report and observation and say "this happens" it becomes a claim - and that is what we see. As for testing your observations/claims - that is really quite simple and need cost very little - even nothing. All it takes is for somebody independent to change between two sources in a random fashion, and for you to see if you can tell which is which without any sighted bias. This was the source of my surprise, because your training would lead me to believe that this was the minimum you would do before even considering reporting to the world. You have indeed stated that you have no explanation for what you hear, but that really isn't so, is it? You have all the explanation you could wish for in your training - yet you refuse to apply it. Why? I have heard big differences between things myself in the past which have evaporated when I didn't know which was which. Because of that, I believe that reporting differences based on circumstances which permit sighted bias is simply a pointless exercise. ANd anybody even slightly versed in the principles of psychological testing should be well aware of that. Of course it is great for a chat down the pub, but not very helpful in an actual audio forum like this. d Pearce Consulting http://www.pearce.uk.com |
CD transports and resonance
On Sat, 6 Nov 2004 20:22:49 -0000, "Rob"
wrote: "Don Pearce" wrote in message ... On Sat, 6 Nov 2004 19:42:58 -0000, "Rob" wrote: "Stewart Pinkerton" wrote in message ... On 06 Nov 2004 11:27:16 GMT, ohawker (Andy Evans) wrote: I have no wish to 'endow' (DP) anything. I'm reporting less distortion in highly modulated passages when a transport is damped. No, you're reporting that you *think* something is happening. You have as yet shown no indication that anything *real* is occuring. -- If I were Andy I'd be feeling like someone asked to prove, for ever, evidence of something that doesn't exist in the empirical world. Andy can't prove what he hears, and I'm inclined to think he (of all people) is aware of placebo-type effects. Why can't you turn this round - instead of asking him to prove it, you disprove it. Simple hypothesis - test it and see what happens. You haven't really thought this one through, have you. If somebody says there is no difference, then in any test all they have to say is "I can't hear a difference". That applies whether the difference exists or not. If somebody claims to hear a difference, they can prove it conclusively by identifying by sound alone - job done. :-). Complete and utter nonsense. The proper test is antithesis - look it up. Andy surprises me rather with his claims because he is fairly uniquely positioned in his psychological training to understand the reasoning and processes, yet chooses to ignore all his training and experience. Do you have any evidence of this? Just read his posts. I know that it is not nice to have your row of soldiers knocked down, but the experience can be both illuminating and cathartic. Having knocked them down, of course, you can then move on to something more productive. I really don't think this is what Andy is doing - I see it as a simple test/pastime. I wouldn't presume to judge a person's productivity on the basis of this little exchange. But what do you say to somebody who, when you show them how a conjuring trick is done then says "it must be magic"? I suspect that behind your rather abrupt manner and bluster is a charitable soul trying to dissuade people from throwing time and money at what you see to be a pointless grail. I can't prove it though ;-). Rob I think you are right that many of us here do genuinely want people to listen with their ears and not go blowing valuable time and money on fruitless pursuits. Of course there is the point that the chase itself can be fun - but it is much more fun when yo know that there is some chance of there actually being a prize at the end. There is a chance - that is, er, the point. It may be slim but I find an inquiring mind fascinating. How many massive breakthroughs to our understanding of the physical world have been made by people who were told 'Nope, it's impossible'. Challenge hegemony. Rob You have the roles reversed here. It is Andy who is saying "no it is impossible" and refusing to investigate further - merely repeating the assertion. The enquiring mind is the one that pulls the phenomenon apart to see what causes it and learns thereby. d Pearce Consulting http://www.pearce.uk.com |
CD transports and resonance
All it takes is for somebody independent to change between two sources in a
random fashion.(snip).. the minimum you would do before even considering reporting to the world. Hello Don - now, are you seriously suggesting that I buy another identical transport (which is an obsolete model), set up a switching device and go out of my way to get a third party to operate it just in order to make an observation to a recreational newsgroup? Some parties on this newsgroups seem to think that before stating anything you should set up a complex DBT which would probably take several days of one's time and require a variety of equipment and third parties. Now if I were saying "I have discovered something new, I'm confident that I'm the first to discover it and I'll be applying for a patent this week and sending my findings to three scientific journals once validation is complete" - then, and only then, would I consider that such demands for DBTs etc had any place on a recreational newsgroup. Andy === Andy Evans === Visit our Website:- http://www.artsandmedia.com Audio, music and health pages and interesting links. |
CD transports and resonance
The enquiring mind is the one that pulls the phenomenon apart to see what
causes it and learns thereby. (DP) Well now, I still have no progress with anybody that has 'pulled this phenomenon apart' as you put it, no suggestion of a cause and until I have any empirical evidence to back up claims that resonance damping has no effect, I seem to be without anything to learn. === Andy Evans === Visit our Website:- http://www.artsandmedia.com Audio, music and health pages and interesting links. |
CD transports and resonance
On 06 Nov 2004 21:11:36 GMT, ohawker (Andy
Evans) wrote: The enquiring mind is the one that pulls the phenomenon apart to see what causes it and learns thereby. (DP) Well now, I still have no progress with anybody that has 'pulled this phenomenon apart' as you put it, no suggestion of a cause and until I have any empirical evidence to back up claims that resonance damping has no effect, I seem to be without anything to learn. You have had the explanation. You are sufficiently motivated to hear a difference that you do. Before you demand evidence that resonance damping has no effect, you must show how it could possibly have ANY effect. That is the extraordinary claim, so that is what must be demonstrated. d Pearce Consulting http://www.pearce.uk.com |
CD transports and resonance
On 06 Nov 2004 21:08:38 GMT, ohawker (Andy
Evans) wrote: All it takes is for somebody independent to change between two sources in a random fashion.(snip).. the minimum you would do before even considering reporting to the world. Hello Don - now, are you seriously suggesting that I buy another identical transport (which is an obsolete model), set up a switching device and go out of my way to get a third party to operate it just in order to make an observation to a recreational newsgroup? Some parties on this newsgroups seem to think that before stating anything you should set up a complex DBT which would probably take several days of one's time and require a variety of equipment and third parties. Now if I were saying "I have discovered something new, I'm confident that I'm the first to discover it and I'll be applying for a patent this week and sending my findings to three scientific journals once validation is complete" - then, and only then, would I consider that such demands for DBTs etc had any place on a recreational newsgroup. Andy Well, you *are* saying you have discovered new, and this news group is the publishing vehicle of your choice. So this, I'm afraid, is where your discovery is going to be challenged. What you claim (observe) goes against everything that those of us who understand how CDs work believe is possible. This makes the claim extraordinary. Of course we can't simply say well done, we didn't know that. Such a response would be preposterous given our knowledge (call it belief if you like). So we say no, your hearing has been deceived in ways you are well accustomed to from your experience in psychology. Now you can go on repeating the assertions, and we can go on saying you are wrong until you prove them, confident in the knowledge that you can't. But that is a pretty fruitless exercise. So if you want your extraordinary claim to stand up, then I'm afraid that yes, you are going to have to get yourself another similar transport and get somebody to blind switch between the two for you. Without that you are simply the bloke down the pub saying "my CD player sounds miles better when I bolt it to a slab of aluminium" while all your mates nod sagely into their beer. Sorry, but that is how it is. d Pearce Consulting http://www.pearce.uk.com |
CD transports and resonance
Well, you *are* saying you have discovered new, and this news group is the
publishing vehicle of your choice. (DP) You're giving me ideas beyond my station here! And === Andy Evans === Visit our Website:- http://www.artsandmedia.com Audio, music and health pages and interesting links. |
CD transports and resonance
You have had the explanation. (DP)
I'd like to be a little more precise here - I've had 'an explanation'. Andy === Andy Evans === Visit our Website:- http://www.artsandmedia.com Audio, music and health pages and interesting links. |
CD transports and resonance
On 06 Nov 2004 22:00:01 GMT, ohawker (Andy
Evans) wrote: You have had the explanation. (DP) I'd like to be a little more precise here - I've had 'an explanation'. Andy How many do you need? The one you have had is one that has been validated in many situations over many years and must be more than familiar to you in your professional field. Why do you reject it in favour of an explanation that makes no sense in any terms whatever? d Pearce Consulting http://www.pearce.uk.com |
CD transports and resonance
On 06 Nov 2004 21:58:20 GMT, ohawker (Andy
Evans) wrote: Well, you *are* saying you have discovered new, and this news group is the publishing vehicle of your choice. (DP) You're giving me ideas beyond my station here! And And the rest of my post? It was all pretty relevant. d Pearce Consulting http://www.pearce.uk.com |
CD transports and resonance
Rob wrote:
Why can't you turn this round - instead of asking him to prove it, you disprove it. Simple hypothesis - test it and see what happens. Ok, I'll bite. will you accept that two identical bitstreams will reproduce identically through a given DAC? If so I can disprove andys theory by ripping a CD on my PC at 30ish speed and comparing the bitstreams. I've done this before, with some pretty manky CDs, and have successfully extracted identical bitstreams on two consecutive runs. I've even done it whilst playing loud music too. Will that suffice? |
CD transports and resonance
Andy Evans wrote:
The enquiring mind is the one that pulls the phenomenon apart to see what causes it and learns thereby. (DP) Well now, I still have no progress with anybody that has 'pulled this phenomenon apart' as you put it, no suggestion of a cause and until I have any empirical evidence to back up claims that resonance damping has no effect, I seem to be without anything to learn. Out of curiosity how did you determine it to be a resonance and not merely a vibration? also, is the 'effect' identcal across the whole disc? how would you account for / reason that? |
CD transports and resonance
Andy Evans wrote:
I have made an observation which I consider to be worth pursuing, and one which as we all know is paradoxical in binary terms. I've stated that I have no explanation for what I hear, that I do hear it, that I can't measure it because I have neither the equipment nor the knowledge. I thought you said you had a scope... |
CD transports and resonance
Andy Evans wrote:
Hello Don - now, are you seriously suggesting that I buy another identical transport (which is an obsolete model), set up a switching device and go out of my way to get a third party to operate it just in order to make an observation to a recreational newsgroup? Well you cant really say your findings show anything as yet. Given the nature of your subject I'd say it'd be sufficient to use ANY other transport with a digital output. the pricib=ple being that when your third party randomly switches them you wont be able to tell which is which. btw, you ought to be able to switch them by swapping the cabling ruond. no need for fancy gear. |
CD transports and resonance
Rob wrote:
"Ian Molton" wrote in message ... Andy Evans wrote: Apart from the fact that I can hear it. There's no assurance that you have any technical knowledge that can explain it. I don't mind the fact that you can't explain it - our knowledge always has limitations. Your ear is a transducer - pressure to electrical impulses. we have mics available that can hear stuff humans cant (demonstrably - animals can hear the difference in the recordings where humans cant) therefore the tool to measure your claimed effect is available. Hi - have you got a link? Try any half decent pro mic. The ECM8000 ought to suffice even. |
CD transports and resonance
Andy Evans wrote:
I have no idea why, btw, but I'd be curious if I could be bothered. Hello Rob - you summed up the situation quite neatly. Like you I have no idea why, and as you can see I have had no explanation. I put some time into this because, like you, I was curious and in my case I had some mechs lying about. New CD transports aren't exactly chump change, so it makes sense to start with what one has. Andy They sodding well are... I picked up a 2x transport WITH a play button on the front fascia, for 5ukp, and that was over 6 years ago. (computer fair) a brand new CD transport is in the region of 15ukp tops. |
CD transports and resonance
Out of curiosity how did you determine it to be a resonance and not merely a
vibration?(IM) I haven't 'determined' anything, and I don't know what the cause is. also, is the 'effect' identcal across the whole disc? how would you account for / reason that? There may be more detail, but I wouldn't be sure that I could tell that in an AB test. What I heard more clearly (or believe I heard if you prefer) was an improvement in resolution of more highly modulated parts. === Andy Evans === Visit our Website:- http://www.artsandmedia.com Audio, music and health pages and interesting links. |
CD transports and resonance
I enclose what appears to be other people saying similar things. I am not
saying any of these opinions are causally linked to the same phenomenon, and I have no way of knowing what they heard or didn't hear, so this is purely for information. (Audio Asylum search) Vibrations within components are very complex and very dependent on the exact equipment, shelving, etc. There is no reliable way to predict the exact sonic characteristics of the types of changes you're thinking of making. I believe the only way to know what the changes may do is to try them. In the case of the top inner tube making a big difference to your transport, I'm willing to bet that the top tube damped chassis vibration/resonance. If this hunch is correct, then you may find some significant sonic benefits by opening the chassis and applying some internal damping to the chassis and/or boards (don't forget the clock). Over-damping in this instance seems to be caused by the flexibility of the (plastic) case, which can affect resonance of components and vibrations transmitted to the cheap transport (from both inside and outside), which lead to a change in the sound. Now, the case of the exorbitant Burmeister combo vs. a cheap SACD player. People are NOT simply hearing 16/44 vs. DSD here! In the Burmeister, they are hearing the sonic advantages of the combo's exorbitant BMW-level transport mechanism, optical reading system, analog output stage, digital decoding circuitry, DA conversion, power supply, resonance-damping etc. We need to be careful about what we are comparing. We are NOT comparing 16/44 vs. DSD. We ARE comparing other component design parameters like analog output stages, resonance control, Power Supply purity, DA circuitry design, optical reading mechanisms etc. DSD processing does not automatically absolve all sins in sloppy design of power supplies, reading mechanism, decoding circuitry, DA circuitry, resonance damping and analog output stages. I feel the transport/anti-resonance features of the scd-1 are very beneficial to it's sound. Thin metal vibrating will work its nastiness into the ability of the transport to read the digits. The SCD-1 with its built like a tank walls and added kevlar damping, well I'm sure have something to do with its great sound. Finally, a precautionary note; there is also too much of a "good thing" ... ie. too much heavy/mass damping (over-damping ?) can sometimes have adverse effects, ie., "tempering/slowing down" subjective "dynamics/liveliness/pace". Only recently, a friend with a Sony XA7ES cdp experienced this problem of "over-damping" ... he initially had 2 granite slabs sandwiching his XA7ES in between, and later discovered the cdp sounded subjectively "better/livelier" with only a granite slab on top of the cdp, with the normal glass shelf re-installed back into his audio rack. i've treated a CD player fully with blu-tak and pieces of wood, and had significant improvements.. .in CD players the damping of the transport housing can be especially beneficial.. === Andy Evans === Visit our Website:- http://www.artsandmedia.com Audio, music and health pages and interesting links. |
CD transports and resonance
Andy Evans wrote:
Out of curiosity how did you determine it to be a resonance and not merely a vibration?(IM) I haven't 'determined' anything, and I don't know what the cause is. also, is the 'effect' identcal across the whole disc? how would you account for / reason that? There may be more detail, but I wouldn't be sure that I could tell that in an AB test. What I heard more clearly (or believe I heard if you prefer) was an improvement in resolution of more highly modulated parts. Whats a highly modulated part? what do you mean by improvement in resolution? also why do you think you wouldnt be able to hear the result in an AB test? was the effect constant across the disc? |
CD transports and resonance
Andy Evans wrote:
i've treated a CD player fully with blu-tak and pieces of wood, and had significant improvements.. .in CD players the damping of the transport housing can be especially beneficial. You may get better damping if you **** into it. dont forget to switch it on first... |
CD transports and resonance
In article ,
Andy Evans wrote: Well now, I still have no progress with anybody that has 'pulled this phenomenon apart' as you put it, no suggestion of a cause and until I have any empirical evidence to back up claims that resonance damping has no effect, I seem to be without anything to learn. Err, just what resonance are you damping? Bolting a plate to the case is likely to alter the resonance of *that case*. Why should that make a difference to the drive or electronics? -- *If horrific means to make horrible, does terrific mean to make terrible? Dave Plowman London SW To e-mail, change noise into sound. |
CD transports and resonance
In article ,
Andy Evans wrote: What I heard more clearly (or believe I heard if you prefer) was an improvement in resolution of more highly modulated parts. Given the time taken in fitting the plate this could easily be explained by listening at a higher level or the ambient noise being lower. Or the coffee or alcohol kicking in. There are so many variables with a time lapse both in circumstances and your hearing that I'm surprised you can't see this. -- *Hard work has a future payoff. Laziness pays off NOW. Dave Plowman London SW To e-mail, change noise into sound. |
CD transports and resonance
Bolting a plate to the case is likely to alter the resonance of *that case*.
Why should that make a difference to the drive or electronics? (DP) Hello Dave - that's exactly the question I'm asking. === Andy Evans === Visit our Website:- http://www.artsandmedia.com Audio, music and health pages and interesting links. |
CD transports and resonance
Given the time taken in fitting the plate this could easily be explained
by listening at a higher level or the ambient noise being lower. Or the coffee or alcohol kicking in. There are so many variables with a time lapse both in circumstances and your hearing that I'm surprised you can't see this. All the above are, indeed, factors that you would want to ask about. I don't drink more than occasionally and never to excess, and I drink decaff so that rules them out, but you're absolutely quite right to ask. I didn't change the level at all, but ambient noise in London is always present. Another factor I'd suggest is tweeter/ear height - if you get up and sit down, you're unlikely to be in the exact same listening position, particularly since in my case the front panel of the speakers is 6'6" from my ears. The difference in ear position could be 2 to 4" I guess, even sitting in the same place, which would have an effect on the sound. These questions are certainly relevant, and much more constructive than saying 'it's all in your head'. === Andy Evans === Visit our Website:- http://www.artsandmedia.com Audio, music and health pages and interesting links. |
CD transports and resonance
In article , Ian Molton wrote:
will you accept that two identical bitstreams will reproduce identically through a given DAC? It is not clear if this include timing as well as data. I assume both. However, for the sake of clarity if the jitter on the bitstreams were different and the DAC merely replicated the incoming clock on its D/A converter there could be an audible difference. Contrariwise, a good DAC (from an engineering POV anyway) will deal properly with input jitter up to some level and have a D/A converter clock whose jitter is independent. (Although the threshold of audibility of jitter was still not well established the last time I looked - but this might have changed as it was a long time ago). Nevertheless there is a hypothesis which could be tested which could explain Andy's observation. If so I can disprove andys theory by ripping a CD on my PC at 30ish speed and comparing the bitstreams. I've done this before, with some pretty manky CDs, and have successfully extracted identical bitstreams on two consecutive runs. There may be some quirks to consider here too. AIUI, a few years ago only CD-ROM transports used to have three-beam lasers (as opposed to CD-DA transports with a single beam) and were reported to have rather lower first-stage soft read error rates due to better tracking of the CD. So, maybe there is a hypothesis to test here concerning the error performance of the CD transport. This may well have been behind Meridian's use of CD-ROM transports in their CD players years ago when others were still using CD-DA transports. This seems to have changed over the last few years as many audio CD players have come to use three-beam transports too. However, for low enough raw error rates (hard plus soft) this should all get corrected anyway (although, again, CD-DA format error correction is not as good as CD-ROM format error correction). My experience recovering the data from physically damanged audio CDs is the same as Ian M's: until a CD is really bad, multiple extractions on a three-beam CD-ROM transport produce completely identical bitstreams (I'm not including timing here). I have not followed the thread well enough to recall just what CD transport was being used for Andy's initial observation but it is certainly my observation that some transports are audibly worse than others with damaged CDs. I can demonstrate that with the three current transports I have (four including the car player). However I can also demonstrate to myself that the additional vibration isolation I have tried (not the same thing as Andy tried) on my main CD player - a three-beam transport - makes no audible difference for all CDs I have tested (including the damaged ones). -- John Phillips |
CD transports and resonance
Andy Evans wrote:
Following on from previous posts where I found that various damping materials affected the sound of my Pioneer CDP used as transport only (I have an outboard DAC), I've found the same with the CD-Rom I'm now using. I went over to the CD-Rom because the build was more sturdy and there seemed to be a better sound in it, which started to happen when I swapped the switch-mode power supply for a normal toroid PSU. That's the story so far Latest step was to bolt the CD-Rom down to a 10mm slab of aluminium 9.5" by 6.5". This after seeing the Flatfish which is exactly that. It's sitting on the carpet as I write - haven't tried any fancy feet yet! Well, the sound is very noticeably clearer. A CD-Rom vibrates quite a bit in your hand, so I guess this is dampening it usefully. The most noticeable thing is that louder passages are less congested and shouty - they have soothed out audibly. Now I have no idea why resonances affect CD transports, but this is without any doubt what I'm hearing - change the damping, change the sound. I suppose this is back to the debate whether 'bits are bits' or whether the signal is complex and affected by other factors. Since it isn't hard to try, maybe somebody else would like to replicate bolting a CD-rom down to a 10mm slab of alu? I wonder if the measurements would be different on any parameters. Andy Unless you are using the analogue outs, there is no possible reason why the sound ( digital data ) should be remotely in the least interested in your choice of power supply, chassis or whatever. If there is gross damage to / contamination of the media ( or maybe excessive vibration ) the error-correction will kick in ( CDs have a *lot* of inbuilt error correction bits of data ). You might as well suggest that in a PC - you can write better prose by using these techniques - the 'interference' of the switching PSU etc - interfering with your writing skills ! Graham |
CD transports and resonance
Andy Evans wrote: No doubt these will be available soon from all good snake oil outlets. We're talking engineering here - Fays metals, Chiswick. The difference is quite audible, as I said, so I'm interested in knowing how resonance dampening affects CD transports. Andy. It doesn't ! CD transports are designed to tolerate such stuff ( vibration et al ). How on earth do you think one can work in a car otherwise ? Graham |
CD transports and resonance
Andy Evans wrote: I have no wish to 'endow' (DP) anything. I'm reporting less distortion in highly modulated passages when a transport is damped. So far I've had no explanation. I don't mind if this is outside the subjective technical knowledge of posters - our knowledge always has its limits. Are you a troll or a clot ? Digital data can't in any event be 'sweetened'. The zeroes and ones are either there or they aren't. A CD mechanism can only read the data on the disc - it can't change it - as you seem to be suggesting. A CD 'sounds' the way it is - period. Clearly - converter accuracy will affect the final result ( that's analogue circuitery ) - but the digital part is either there or it isn't. Maybe you are experiencing 'error correction' on a poor quality / cheap mechanism ? That *might* disturb the digital data, but has zero to do with type of power supply or large lumps of metal. Graham |
CD transports and resonance
"Ian Molton" wrote in message ... Rob wrote: Why can't you turn this round - instead of asking him to prove it, you disprove it. Simple hypothesis - test it and see what happens. Ok, I'll bite. will you accept that two identical bitstreams will reproduce identically through a given DAC? If so I can disprove andys theory by ripping a CD on my PC at 30ish speed and comparing the bitstreams. I've done this before, with some pretty manky CDs, and have successfully extracted identical bitstreams on two consecutive runs. I've even done it whilst playing loud music too. Will that suffice? Well, it's one test but even it adds support to the 'vibration matters' hypothesis it wouldn't necessarily explain what's happening. The hypothesis (antithesis if you like) is that 'metal blocks strapped to CD ROMs affect sound'. I can think of tempertaure, media - I don't know, gravity, magnetism, radiation! I just have no idea. My problem with this is a reaction to the absolute dogma of positivist approaches: 'if it measures, it's real'. I have absoltely no technical understanding of the issue. I've read a few articles and follow Jim Lesurf's contributions with interest. JL is probably the most qualified to explain things from the technical/quantitative/positivist viewpoints - and you will note his reply in this context is slightly equivocal - there is 'wiggle room' - and, IIRC, he is/has been a user of dedicated transports, although this may have been to do with DACs, can't remember. Just one thing - would your test show jitter? Rob |
CD transports and resonance
mick wrote: I read somewhere (sorry, can't give a ref) that the error correction on transports intended for audio is more lax than on those intended for data, as your ears are incapable of detecting low error rates but are more sensitive to the gaps caused by error correction. If that is so, then using a data drive for audio may give a different sound, but not one that is necessarily "better" as it will contain a different sort of inaccuracy! I'm sure someone will be able to correct me on this if I'm wrong. There's a lot of error correction capability on a CD. Hamming encoded IIRC. Forget how many bits of error it can correct transparently. Philips / Sony expected early CDs to have lots of errors so needed them to be correctable. Bear in mind that it was expected that early CDs would *need* error correction. I'm sure they are much better now. I can't recall if the CD standard includes 'error concealment'. Anyone know ? The German broadcaster WDR ( IIRC) found that subjective differences between *DAT* transports was due to head misalignment causing error concealment to kick in. Some units suffered more than others. Error *concealment* kicks in when there aren't enough valid bits to transparently *correct*. Error *concealment* is *not* audibly transparent. I doubt that CDs are troubled by this though. Graham |
CD transports and resonance
Andy Evans wrote: I could tell you how to easily do a representative set of measurements(AK) But evidently you can't explain an obviously audible phenomenon. Audible to only you matey ! Clowns like you are two a penny. You *admit* you know nothing about digital data methods and then try and tell us you know more about the stuff sounds ! Graham |
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