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#1
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I recently changed my speaker cable setup and was very surprised at
the difference in the sound. Basically I moved from having entry-level Van-Den-Hull skyline cables single-wired to my speakers to bi-wiring with the Skylines on the woofers and Kimber-Kables 4TC for the tweeters. I was rather astounded at the difference in the sound. To be honest I was not expecting much change, if any and only did the upgrade because of a very good deal on the 4TC. Instead I am now very convinced that cabling considerations may be, although not the most important aspect, essential to any system and not something to be ignored. Here is my pseudo-scientific explaniation. A few years ago I had a summer job of network support for a small office. At the time There were about 40 computer workstations with about 4 printers. One of my jobs was to set it up so that all of the workstations would have access to a printer. This required the purchasing of a lot of serial and parallel cables to attatch computers to printer-sharing boxes. The use of high quality cabling was ABSOLUTLY essential for this purpose. Quite simply, using generic cables more than about 2m was impossible for parallel printer cables. There was to much noise and signal loss for the succesful and reliable transmission of data. However, by using much more expensive shielded low capacitance cables runs could be as long as 10m or even 15m. Although serial cables (much lower speed signals) were not as finicky, there were still issues with long runs with cheap cabling. Often I had to reduce the data speed from 128kb/s to 64kb/s What does all of this have to do with audio cables you may ask. Everything. Cables essentially serve as carriers of data. Assuming as a baseline the bandwidth of a cd (44000*16bits per channel = 704 kb/s) the amount of data being transmitted is very considerable. if one sample has a value of 5024 then that exact value must be what is found at the other end of the interconnect/cable. If the value recorded at the other end is 5024 +/- 1 then we are losing almost 2 bits of resolution on the sound or a drop in signal to noise of 12db. Since the CD specification came from studies of human hearing this loss of two bits is definetly noticable. Transmitting 704kb/s over a serial connection would be quite a trick. It can be done but only if care is taken into the way that the signal is transmitted. Obviously this represents a much lower data rate than ethernet connection but we must also consider that the type of signal is very different. Speaker cables and interconnects can't use modulation of high frequency signels(measured in Mhz and gHz), Rather the method of signal tranmission is more like amplitude modulation with relatively low (measured in kHz) to extremely low frequencies (measured in Hz), where microvolts may represent the difference between 16 bits and 14 bits of data being transmitted. With speaker cables the difference is even more profound. Not only must the source generate this signals with considerable voltage and current, but the speaker's themselves the recipients are also acting as sources of noise being transmitted back down the line. I would suggest that there is a significant amout of data distortion present even when using the finest amplifiers with excellent short cables. As I said I only begain thinking about this after noticing a huge difference to the sound of my system after changing the speaker cables. Now I am just tring to come up with the theory to explain my observations. Since I am somewhat familiar with the limitations of cabling in other applications (computer data transmission) I am trying to look at the mystery of the audable differences of cables from a data point of view. My System Source:Cambridge Audio D300SE PAdcom GFP-555 MKII Power:Bryston 3BST Speakers:Energy Exl-26 Interconnects:Van-Den-Hull D300SE MKIII Cables Top : Kimber 4TC Cables Bottom : VanDenHull Skyline |
#2
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#4
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(Richard D Pierce) wrote in
: Richard D Pierce ) wrote: (extensive snipping) : You have made a change and you seem to have noticed a : difference. You have a "theory" about "data distortion." : Fine. In order for a theory to be at all useful, it needs to be : testable. I am not going to argue with your observation that you : seem to have heard a difference, rather on your rationalization : of the difference. You claim something about "data distortion." : Well, if the signal IS so distorted, a simple null test will : either support or refute your theory's validity on its face. : SImply compare the input to the cable to its output with a : system whose smallest resolvable change is smaller than your : claimed distortion. If a difference is measured, then chalk one : up for your theory. If none is measured, it's a clear blow : against it. : Well, indeed, such measurements HAVE been made, and not a single : cable of even remotely competent construction has exhibited : differences even remotely approaching the levels you are : claiming. That would suggest your theory is wrong. : The confusion between information content and data rate itself : that is the assunmed basis for your theory is itself on very : shakey ground. I agree with almost everything you've said ![]() OTOH, I can understand how he comes to the conclusions he comes to. As someone with 25 years in IT, I have thrown away dozens of supposedly competently designed SCSI/serial cables that don't work. SCSI cables in particular are darn hard to to get right for the newer higher speeds - and it all seems to come down to how the cable(s) is insulated. I also agree that this doesn't necessarily have anything to do with audio transmission. However, IMHO, this business about insulation continues to bedevil me. Since it does play havoc with digital signal transmission, it seems to me hard to leap to an absolute conclusion that it has no effect in the analog audio world. No hard science on this yet, but it is a very active field of research... -- Lou Anschuetz, Network Manager, CMU, ECE Dept. |
#5
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On 10 Sep 2003 15:47:47 GMT, Lou Anschuetz wrote:
As someone with 25 years in IT, I have thrown away dozens of supposedly competently designed SCSI/serial cables that don't work. SCSI cables in particular are darn hard to to get right for the newer higher speeds - and it all seems to come down to how the cable(s) is insulated. I also agree that this doesn't necessarily have anything to do with audio transmission. However, IMHO, this business about insulation continues to bedevil me. Since it does play havoc with digital signal transmission, it seems to me hard to leap to an absolute conclusion that it has no effect in the analog audio world. No hard science on this yet, but it is a very active field of research... It's certainly *not* an active field of research for audio purposes. All that research was done many *decades* ago in the communications and measurement industries, and there are certainly significant effects at multi MegaHertz frequencies. Drop the frequency by a factor of a thousand, and you also drop the effects by a factor of a thousand........ At audio frequencies, you will *never* measure artifacts in cables above -140dB referred to a 10 vrms signal, and usually much lower than that, right at the -160dB or so limit of the measuring gear. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#6
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(Stewart Pinkerton) wrote in news:bjnmtj014u5
@enews3.newsguy.com: On 10 Sep 2003 15:47:47 GMT, Lou Anschuetz wrote: As someone with 25 years in IT, I have thrown away dozens of supposedly competently designed SCSI/serial cables that don't work. SCSI cables in particular are darn hard to to get right for the newer higher speeds - and it all seems to come down to how the cable(s) is insulated. I also agree that this doesn't necessarily have anything to do with audio transmission. However, IMHO, this business about insulation continues to bedevil me. Since it does play havoc with digital signal transmission, it seems to me hard to leap to an absolute conclusion that it has no effect in the analog audio world. No hard science on this yet, but it is a very active field of research... It's certainly *not* an active field of research for audio purposes. All that research was done many *decades* ago in the communications and measurement industries, and there are certainly significant effects at multi MegaHertz frequencies. Drop the frequency by a factor of a thousand, and you also drop the effects by a factor of a thousand........ At audio frequencies, you will *never* measure artifacts in cables above -140dB referred to a 10 vrms signal, and usually much lower than that, right at the -160dB or so limit of the measuring gear. While there may be no _audio_ research going on in this area, there is other continuing research on insulation properties at low frequencies. At very low voltages, with frequencies just above the audio range, this is certainly active work. There are also known effects at 60hz, which is in the audio range. So, there are effects at very low voltages at reasonably low frequencies and there are effects at higher voltages at audio frequencies - I find it hard to simply assume that in the middle of that curve there are absolutely no effects. I will certainly grant that it might as easily not be the explanation for anything, but there is reason to suspect... As I started out, this may not be directly applicable, but there are clear issues here that are not QED. I think it is unwise to characterize all of materials science as old/completed science. I'm willing to let the continuing efforts see if they show promise and not just assume they won't. -- Lou Anschuetz, Network Manager, CMU, ECE Dept. |
#7
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Lou Anschuetz wrote:
(Stewart Pinkerton) wrote in news:bjnmtj014u5 @enews3.newsguy.com: At audio frequencies, you will *never* measure artifacts in cables above -140dB referred to a 10 vrms signal, and usually much lower than that, right at the -160dB or so limit of the measuring gear. While there may be no _audio_ research going on in this area, there is other continuing research on insulation properties at low frequencies. At very low voltages, with frequencies just above the audio range, this is certainly active work. Can you provide a little more detail on what research you are talking about? There are also known effects at 60hz, which is in the audio range. Again, what effects are you talking about? So, there are effects at very low voltages at reasonably low frequencies and there are effects at higher voltages at audio frequencies - I find it hard to simply assume that in the middle of that curve there are absolutely no effects. I will certainly grant that it might as easily not be the explanation for anything, but there is reason to suspect... What are those reasons? As I started out, this may not be directly applicable, but there are clear issues here that are not QED. What are those clear issues that have to do with delivering audio signals to speakers, or from one output to another input? I think it is unwise to characterize all of materials science as old/completed science. Now you are making a straw man. For speaker cables and interconnect cables, there is no new discovery, or research to be done, in the last several decades, as far as I know. I'm willing to let the continuing efforts see if they show promise and not just assume they won't. |
#8
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Lou Anschuetz wrote:
......large snips....... But, I also know that cables do sometimes act in funny ways. Until someone can adequately model every potential agent acting in random ways concurrently in a cable, there is room for some healthy scepticism about whether or not they make a difference. -- Lou Anschuetz, Network Manager, CMU, ECE Dept. Isn't it interestig that no manufacturer, seller, designer or enthusiast has ever produced results from a bias controlled listening test that nominally competent wires (rca, XLR or speaker cable) have any sound of there own. I've conducted a half dozen experiments (ABX, Cable Swap) with more than 20 subjects over the years where cable differences, if present, should have been a sonic factor (in 4 cases subjects used their reference systems and had verified those "differences," one subject was the 'designer' of his regionally branded cables and in total over half compared their own cables to another. I think the lack of positive, replicable evidence is enough for everyone to be skeptical about whether sonic cable differences exist. |
#9
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Lou Anschuetz wrote:
chung wrote in news:d6N7b.413447$uu5.75550@sccrnsc04: Lou Anschuetz wrote: (Stewart Pinkerton) wrote in news:bjnmtj014u5 @enews3.newsguy.com: At audio frequencies, you will *never* measure artifacts in cables above -140dB referred to a 10 vrms signal, and usually much lower than that, right at the -160dB or so limit of the measuring gear. While there may be no _audio_ research going on in this area, there is other continuing research on insulation properties at low frequencies. At very low voltages, with frequencies just above the audio range, this is certainly active work. Can you provide a little more detail on what research you are talking about? Actually no. It would be unwise for me to comment on unpublished research. Well, you were making it sound like it is research that is well known to be ongoing. Is it active work only at your place of employment? There are also known effects at 60hz, which is in the audio range. Again, what effects are you talking about? So, there are effects at very low voltages at reasonably low frequencies and there are effects at higher voltages at audio frequencies - I find it hard to simply assume that in the middle of that curve there are absolutely no effects. I will certainly grant that it might as easily not be the explanation for anything, but there is reason to suspect... What are those reasons? As I started out, this may not be directly applicable, but there are clear issues here that are not QED. What are those clear issues that have to do with delivering audio signals to speakers, or from one output to another input? Quality, type of insulation (in regards to EFI, EMI, RFI, etc. etc.). Quality/type of connectors in regards to things as varying as insertion loss (fiber), crimped vs. soldered (turns out that crimping fiber cables may be better than glueing - interesing in that a lot of audio equipment manufacturers are alleging the same thing to be true with copper. Obviously different reasons/effects, but new information. This is not exhaustive, but just some an example. But shielding issues are well understood and practically non-issues with speaker cables. Of course, the fact we understand these things does not prevent from someone incompetent to screw up the implementation, but you can't say that our understanding is incomplete because someone screws up the implementation. What new informatin has come out about audio cables in the last 30 years? (We're not talking about fiber-optical cables here.) While nature is wonderful, it is also pretty consistent. To believe that the range 20-20,000 is somehow protected or asymptoted out of all effects is, IMHO, pretty bold. No, it's just a range that is easily handled by cables, and it has been handled successfully for decades. We're not talking about delivering kilowatts of power or nano-amps of current here. Let's get practical. Yes, many individual effects can be said to be negligable - but with the complexity of a musical signal, there is the *potential* for multiple small effects to interact. I'm not trying to rule out Occam's Razor here, just pointing out that this stuff is not easy to model perfectly. If such effects are not negligible, how come we still have not found them, after using cables for decades? Do we need to model a cable perfectly to one part in a trillion? Let's get practical. We are talking about deliveriing audio, which is band-limited, at power levels that can be comfortably handled. I think it is unwise to characterize all of materials science as old/completed science. Now you are making a straw man. Not all all... See below For speaker cables and interconnect cables, there is no new discovery, or research to be done, in the last several decades, as far as I know. As I noted above, there is no work specifically related to Audio that I know of. That doesn't establish that there is no link between what is happening research-wise and what happens with audio signals. Let's go back to Materials Science 101 for just a moment.With the exception of a perfect vacuum (which we don't have anywhere) there is no perfect insulator. All materials react in some way to electrical/magnetic fields. Fortunately, electricity mostly acts like water and doesn't "leak out" like alpha particles ![]() insulators around wires do react. I'll certainly grant any day of the week that at low voltages and mostly small frequencies, those reactions may be *very* weak. However, with the complexity of a musical signal, the rules tested for single frequency, single voltage reactions *may* not apply in a linear way. We have been looking for non-linear effects in cables at the current levels required for audio reproduction for decades. We have not found any limitation even at signal to noise ratios of 140 dB. If you know that linearity in a cable is good down to the 140 dB level, then you should feel confident that music, as a complex signal but made up of sinusoids, should have no problem being transmitted faithfully. You don't sweat the details about how complex music is, when it comes to cables. Look at it another way, the non-linearities from the rest of the chain are easiliy a million times worse. Which should you focus on? Not a lot of folks spend a lot of time looking at this (other than high-end cable makers) since there is, frankly, little value or profit. But, you'll also note that there is no uniform, best-of-breed, do-all, be-all cable construction for audio either. No one said that. Mechanical reliability is important. This is the likely outcome of modeling when there are lots of parameters with potential multiple interactions. You are needlessly complicating a straightforward situation. Do you worry about how the indiviudals electrons behave in an amplifier? In fiber optics there is a "best of breed" for insulation, construction - though the crimp-on fiber connector is *new* (relatively) and the result of continuing research. Fiber optics carry optical signals with Gigahertz's of modulation bandwidth. Please have some appreciation for the scale of things. Most every cable user I know of (and I know a lot in both research and manufacturing) check every spool of wire that comes in. A lot of it doesn't pass master. You mean "muster"? That's what they, the marketing guys, want you to believe. Some does, but still doesn't work. How does a piece of copper cable not work? I know of a certain large bulb manufacturer who tests all filament wire, but some that passes still doesn't work right. Again, you have to appreciate the difference in scales. Filaments are totally different, because they have to give light efficiently and last a certain minimum of time. It is a very different application, and it is not pure copper. It may be a slight difference microscopically, but it kills the unit. This is certainly an example of a well-known, well-engineered process that somehow still goes wrong. There is no process that cannot be screwed up, although making a speaker cable comes pretty close. The fact that the process goes wrong does not necessarily mean that there is something esoteric going on. Engineering still has some room to grow to make those manufacturing processes work correctly every time. Hmmm, is it possible that some audio cable manufacturers don't check every spool and thus their general quality is lower - thus producing a "worse" sound? Good research question there. I can't think of a less useful research question. All of us involved with music know that there are effects with every cable. All? Are we talking about normal cables, like the ones they sell at Radio Shack? Are we talking about effects like gauge size vs. current? For those of us doing live sound we try to use the best insulated (typically coax) cables we can to reduce stray effects. Any, every mixing console I've ever seen has a built in 80hz roll off control to eliminate breathing, as well as the occasional 60hz hum that is so prevalent. Are there effects other than shielding that you have seen? You think "breathing" is affected by the coax cable? We all know that that effect penetrates coax cables, which in theory should be mostly immune (and yes, I do know that this is most often the result of the electronics rather than the cabling). No, we don't know that the "breathing" effect "penetrates" cables. Remember that I too hear no differences between competently designed interconnects and toslink cables. I do, however, contend that some speaker cables, for whatever reasons, do sound different. Ehh, perception biases? I also know that testing such cables via human hearing is frought with difficulty. Some early, unpublished (and potentially invalid) research I did many decades ago as an undergraduate suggested that people couldn't even identify their own voice vs. someone else's (even of a different gender!) in some studies. That has the potential to be quite damming in certain areas of research, so might be quite hard to get funding for ![]() listening alone is not to be trusted - thus gives me pause when suggesting any kind of "audio" test of cables will be conclusive. But, I also know that cables do sometimes act in funny ways. Until someone can adequately model every potential agent acting in random ways concurrently in a cable, there is room for some healthy scepticism about whether or not they make a difference. Please list those funny ways, and see if we can sort them out. I think that makes for a much more productive discussion. |
#11
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On 11 Sep 2003 15:25:29 GMT, Lou Anschuetz wrote:
chung wrote in news:d6N7b.413447$uu5.75550@sccrnsc04: Lou Anschuetz wrote: (Stewart Pinkerton) wrote in news:bjnmtj014u5 @enews3.newsguy.com: At audio frequencies, you will *never* measure artifacts in cables above -140dB referred to a 10 vrms signal, and usually much lower than that, right at the -160dB or so limit of the measuring gear. While there may be no _audio_ research going on in this area, there is other continuing research on insulation properties at low frequencies. At very low voltages, with frequencies just above the audio range, this is certainly active work. Can you provide a little more detail on what research you are talking about? Actually no. It would be unwise for me to comment on unpublished research. Hmmmmmmmm. Didn't stop you commenting on it previously...... While nature is wonderful, it is also pretty consistent. To believe that the range 20-20,000 is somehow protected or asymptoted out of all effects is, IMHO, pretty bold. No one suggested that *low* frequencies were exempt, simply that effects which occur at tens or hundreds of MegaHertz have little or no relevance to things that happen below 20kHz. Can you show *any* AC effects below 100Hz? Yes, many individual effects can be said to be negligable - but with the complexity of a musical signal, there is the *potential* for multiple small effects to interact. I'm not trying to rule out Occam's Razor here, just pointing out that this stuff is not easy to model perfectly. It is in fact *trivially* easy to model at low frequencies, and absolutely *no* effects can be shown above -160dB at low frequencies. Let's go back to Materials Science 101 for just a moment.With the exception of a perfect vacuum (which we don't have anywhere) there is no perfect insulator. All materials react in some way to electrical/magnetic fields. Fortunately, electricity mostly acts like water and doesn't "leak out" like alpha particles ![]() insulators around wires do react. I'll certainly grant any day of the week that at low voltages and mostly small frequencies, those reactions may be *very* weak. Indeed so - see above. However, with the complexity of a musical signal, the rules tested for single frequency, single voltage reactions *may* not apply in a linear way. Excuse me? Musical signals are not in fact particularly complex, and *no* non-linearies have been noted anywhere near audible levels. See above. Not a lot of folks spend a lot of time looking at this (other than high-end cable makers) since there is, frankly, little value or profit. Indeed so, probably similar to the number of people who investigate the possibility of the Moon being made from green cheese. But, you'll also note that there is no uniform, best-of-breed, do-all, be-all cable construction for audio either. Well of course there isn't - because *it makes no difference*. This is the likely outcome of modeling when there are lots of parameters with potential multiple interactions. No, it's the likely outcome of the desperate scrabble for difference to provide a Unique Selling Point among cables which *all* sound identical. In fiber optics there is a "best of breed" for insulation, construction - though the crimp-on fiber connector is *new* (relatively) and the result of continuing research. Unfortunately, the 'best of breed', which is the monomode quartz fibre, is not sold by high end audio companies, only professional communications companies - who have been selling it for *decades* at prices well below those asked by so-called 'high-end' audio companies for vastly inferior products. Also, the termination of such fibres is a matter of precision engineering, not 'crimping'. All of us involved with music know that there are effects with every cable. All of us who have tried level-matched blind comparisons know that there is *no* audible difference. Have you ever wondered *why*, when a pool of around $4,000 has lain on the table for more than five years, no one has ever even *tried* to collect it by differentiating two cables? But it has always made me aware that testing by listening alone is not to be trusted - thus gives me pause when suggesting any kind of "audio" test of cables will be conclusive. Oh right, so cable differences are not audible, but still matter in music reproduction systems? :-) -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#12
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On Thu, 11 Sep 2003 20:15:50 GMT, Lou Anschuetz
wrote: chung wrote in . net: Can you provide a little more detail on what research you are talking about? Actually no. It would be unwise for me to comment on unpublished research. Well, you were making it sound like it is research that is well known to be ongoing. Is it active work only at your place of employment? Lots of places as it turns out. But none I can feel free to disclose. Research dollars come from many places ![]() Oh please! Don't be coy - I worked in military electronics for about twenty years, doing work at audio frequencies that was *thousands* of times more sensitive than domestic audio, and *no* effects due to cabling were *ever* noted, aside from simple microphony. For centuries people were quite happy to believe the sun rotates around the earth - and they did the necessary math. No, they didn't. Those people who did the necessary math realised that this was not the case. Of course, the 'true believers' persecuted them without mercy. Remind you of any modern parallel? :-) Example, hook up my television camera to a snake bundle with multiple analog coax feeds. An hour into shooting the remote monitors show ghosting (known as cable reflections). Change to other coax. After shoot put back the first one - no problem. Jump up and down on cable, twist it, scream at it, etc. It never fails again. Cosmic particles? Pixie dust? don't know - flaw is never found again. Happened to me last month. Cable tests perfectly (as do the electronics). Oh please! This is just a poor connection. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#13
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(Nousaine) wrote in message . net...
(See remainder of the discussion below ![]() So YOU hear speaker cables? Why not take a cable with 'sound' and compare it to zip cord in a bias controlled listening test and tell us what you find? Why not? Because why should one bother with a $ 600:00 switch and trained assistants if the result is predictable? You'll hear "no difference" just like the 80% or more of the listeners in ALL the reported "bias controlled" listening tests, whatever is being tested: cables, preamps, amps, cd players, dacs, distortion under 2%-everything. And if you score within the "yes" 20% group you'll be told that the goal is now moved and the criteria for the likes of YOU are now set higher. For the record- it was not I , who inroduced the topic of "bias controlled" tests. Unless you meant something else -not ABX. Did you? Ludovic Mirabel Lou Anschuetz wrote: ...snips to specific content ..... chung wrote in . net: Can you provide a little more detail on what research you are talking about? Actually no. It would be unwise for me to comment on unpublished research. I wonder why you mentioned it then? What new informatin has come out about audio cables in the last 30 years? (We're not talking about fiber-optical cables here.) I've already stated that little (if any) research is being done at sites other than cable companies on _audio_ cables. That doesn't mean that other things learned have no effect. This is a falsifiability issue. There is no audibility 'research' being done at any high-end company. But experiments that I've personally performed indicate that none is seemingly necessary. While nature is wonderful, it is also pretty consistent. To believe that the range 20-20,000 is somehow protected or asymptoted out of all effects is, IMHO, pretty bold. No, it's just a range that is easily handled by cables, and it has been handled successfully for decades. We're not talking about delivering kilowatts of power or nano-amps of current here. Let's get practical. For those same decades people have heard differences. No they have only 'claimed' such. No interested party has ever produced a bias-control listening test that nominally competent audio interconnects and speaker cables have any sound of their own. You argue it is bias (which it *may* be), but there may be other explanations as well. Such as? Most every cable user I know of (and I know a lot in both research and manufacturing) check every spool of wire that comes in. A lot of it doesn't pass master. In what ways. I once had a job as a sheey metal expediter and we tested every coil that came in. Some were rejected but mostly because it was the wrong size or the spool wouldn't fit on the decoiler (one time because it was stamped in ink "ford reject" although there was nothing else wrong with the steel.) Remember that I too hear no differences between competently designed interconnects and toslink cables. I do, however, contend that some speaker cables, for whatever reasons, do sound different. Ehh, perception biases? It is one of the possibilities, yes. I just don't happen to think it is the only one. Hence my relating the story below. There has been no experimental listening test results that indicate otherwise. I suppose that on occasion that the interface 'boxes' might produce an effect but IME I've not found this to be the case. I also know that testing such cables via human hearing is frought with difficulty. Some early, unpublished (and potentially invalid) research I did many decades ago as an undergraduate suggested that people couldn't even identify their own voice vs. someone else's (even of a different gender!) in some studies. That has the potential to be quite damming in certain areas of research, so might be quite hard to get funding for ![]() testing by listening alone is not to be trusted - thus gives me pause when suggesting any kind of "audio" test of cables will be conclusive. So if you can't 'hear' the effect, why bother? No one argues that measurements made at the microscopic level can always find variations that are not visible with the naked eye (or audible with the naked ear) so why would we care? But, I also know that cables do sometimes act in funny ways. Until someone can adequately model every potential agent acting in random ways concurrently in a cable, there is room for some healthy scepticism about whether or not they make a difference. Even if they do operate in funny ways unless it affects the sound quality the effects are nearly always noise or loss of transmission, which means a system error of some type. Those circumstances, which you describe below, need fixing but have nobearing on the innate sound quality of the transmission media. Here's mu 'funny wire' story. When making soem speaker measurements my computer based test gear kept giving me an error message indicting that I might have had a wire failure. Sure enough substituting a different cable seemed to fix the problem although that cable tested good for conductivity. Next time around I got the same message; and hunted the problem down to re-seating the ISA card in the computer. Another time, long ago, I had an intermittent channel drop-out problem that would fix itself whenever I touched any piece of equipment in the rack. Turned out to be a tone arm lead wire that was broken behind the rca plug and would operate only intermittently. Neither of those conditions had any bearing on the sound quality of the wires. The lesson I learned from the latter is not to expect high-end wire to be reliable. Please list those funny ways, and see if we can sort them out. I think that makes for a much more productive discussion. Not sure how that helps unless you follow me around ![]() Example: take two new snake (bundle cables) out on stage. Check each one for all normal effects. Thirty minutes into the show one connector starts picking up a flourescent light. The rest of the individual coax's don't. Declare this one bad. Accidentally use the same coax in the same bundle the next night - works fine. Example, hook up my television camera to a snake bundle with multiple analog coax feeds. An hour into shooting the remote monitors show ghosting (known as cable reflections). Change to other coax. After shoot put back the first one - no problem. Jump up and down on cable, twist it, scream at it, etc. It never fails again. Cosmic particles? Pixie dust? don't know - flaw is never found again. Happened to me last month. Cable tests perfectly (as do the electronics). But you're not talking about home audio grade wires or conditions here. And even if so; what does operating faults like this have to do with the 'sound' of tranmission media? I *never* assume that cables will act as theory says. 1/20 or so times they stop acting normally. Many times we find a flaw, many times we don't. All the video/audio guys I know bring lots of extra cabling. Sure, many of the failures are going to be mechanical. Sometimes they aren't. I'm pretty sure that the failures I've just documented aren't perceptual bias ![]() issues, there is clearly something else going on. Either it is just magic, or the cables are being affected by *something* in the environment. I'm thinking the examples you used were probably all mechanically related. If those cables, made for professional use, can exhibit non-easily explained behaviors, I find it hard to believe that speaker cables don't as well. I'm not attempting to *prove* anything - just provide a rationale for why I remain sceptical about cables all sounding the same. I wish they did to me too ![]() |
#14
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#15
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In article , Lou Anschuetz
writes: OTOH, I can understand how he comes to the conclusions he comes to. As someone with 25 years in IT, I have thrown away dozens of supposedly competently designed SCSI/serial cables that don't work. SCSI cables in particular are darn hard to to get right for the newer higher speeds - and it all seems to come down to how the cable(s) is insulated. I also agree that this doesn't necessarily have anything to do with audio transmission. However, IMHO, this business about insulation continues to bedevil me. Since it does play havoc with digital signal transmission, it seems to me hard to leap to an absolute conclusion that it has no effect in the analog audio world. No hard science on this yet, but it is a very active field of research... Well, I'm on a plane flying from Beijing to Hong Kong (and on to Melbourne, Australia) listening to Chinese Pop music in my headphones, and nothing to do, so I thought I would just jump in here! Why do some cables work on signal X but not with signal Y? The answer is simple: wavelength. (The answer is simple, the explanation is a little more complicated.) Every signal, data, audio, video, etc, etc. occupies one or more frequencies. Each frequency has a wavelength, that is, there is an electromagnetic wave moving down the cable that has a specific length. This can be calculated by dividing 300,000,000 by that frequency. (The answer comes out in meters, so us backwards USA types have to multiply by 3.28 to get to feet.) If you look at 20 kHz (or you can pick any frequency you want), that gives you a wavelength of 15,000 meters (about 9 miles). What that means is that the impedance of the cable (how it reacts to frequencies) is of no consequence. Most engineers agree that the ACTUAL critical distance is 1/4 wavelength which is, in this case 2.25 miles, still too far to have any effect. This distance is also affect by the plastic around the conductors. This affects the speed "velocity" of the signal. (Signals only move at the speed of light in a vaccum, i.e. outer space. If you ever have a chance to check out your speakers there, be sure and give me a complete test report!) Let's say your interconnect cables were the worst ever made (a "velocity of propagation" of 50%). You would multiply the wavelength by 50% so we're down to 1.12 miles. Anybody with one mile speaker cables? data cable? mic cables? video cables? audio cable? Well, yes, there are people with AUDIO cables of that length or more. They call themselves the TELEPHONE COMPANY. And the maximum distance between your home and your central office is 13,000 ft. (over 2 miles). But the twisted pairs they use (even fancy new ones, Category 3) are not the correct impedance (too expensive). Luckily, the audio on your phone ends at 3500 Hz. You can calculate the bandwidth and see you can go VERY far before you need to have impedance-specific twisted pairs. I'll be honest and tell you that I don't know the actual occupied bandwidth of a 56k data signal. (I think it's NRZI Manchester Coded, that would make it 28kHz bandwidth.) I'm sure you note that this puts it on the edge for performance if you are far from the central office, and you can't always get dialup that fast. And you'll understand why in the USA, the FCC now mandates that all telephone wiring must be Category 3 or better. Category 3 is impedance-specific (100 ohms) data cable. But there are other reasons the FCC made this a standard besides distance. The signals either go back to the source or simply stop in the cable (called "standing waves") and then radiate all that reflected energegy into cables around them. That's why the phone company is trying to use data cable, to avoid "alien crosstalk" (between cables). That's why you can use crappy interconnect cables that come free with your receiver and it all sounds pretty good. They aren't long enough to make a difference. As long as you have continuity (electrical signal flow), you'll be just fine. But what if you use that cable for DIGITAL (i.e. S/PDIF). Suddenly we're sampling that audio at 44.1kHz (like a CD), and the bandwidth is defined as 128 times the sampling (5.6448 MHz, if memory serves). Let's just use 6 MHz to make it easy. (If you don't want easy, do it yourself.) 300,000,000 divided by 6,000,000 = 50 meters. 1/4-wavelength = 12.5 meters or about 44 feet. How long is your cable? 3 ft? 6 ft? No problem. It's still not LONG enough to make a difference. Now, if you want to send S/PDIF to the other end of the house, that might be 40 ft. or even more. What would you do? Be sure and use cable which is the correct impedance. S/PDIF requires 75 ohm cable (75 ohm cable has the lowest signal loss "attenuation" so it is used for many applications where low loss is required). What if you get a really long piece of crappy cable? What impedance is it? Who knows!! And what will happen is that the signal, which will require a 75 ohm "transmission line" and not see it. The farther it is away from 75 ohm the more the signal will be REFLECTED back to the source and not get to the other end. This is called "return loss" in the cable world. You send me the actual impedance of your cable and I can calculate the mismatch and the return loss. But, if you get the right 75 ohm cable, how far can you go? It depends on the size of the wire (gage) in the middle. Let's assume it is a 20 AWG center (such as Belden 1505A, the world's most popular coax cable and a nice generic size).. Then the cable could go 716 ft. (This is based on a source voltage of 0.5v and a minimum received voltage of 0.2v, at a bandwidth of 5.6448 MHz.) Yup, 700 feet!!! (Snippy aside: try going 700 ft. on a piece of toslink plastic fiber!) And in the digital format, you can be real close to the maximum and the signal (i.e. data/audio) sounds just perfect. But add in one patch cord, or one less than perfect connector, or just a few more feet of cable, and you could be down the slippery slope of the "digital cliff". So, how many of you have to run 700 ft.??? Not many, I assume. This is not to say you shouldn't have cable with low capacitance. Digital signals need low capacitance to keep their sharp edges (i.e. the clock). But (amazing fact that no cable manufacturer ever told you) once you choose the construction (i.e. plastic/dielectric/velocity) and the impedance (i.e. 75 ohms) the capacitance is AUTOMATIC. High velocity foam coax 75 ohm = 15 pF/ft. Old solid polyethylene 75 ohm coax = 20 pF/ft. And this is why you should avoid CATV coax, because it's not all copper in that center conductor (it's copper-clad steel for high-frequency-only applications where only the skin of the conductor is working.) This means the resistance is 5 to 7 times higher than an all-copper center and the distance you can go is 5 to 7 times shorter. (OK, we're down to 100 ft. and you're going 6 ft., but I wouldn't use it.) And all those SCSI cables (at the beginning of this thread) suffer from the same problem. Most of them use generic multiconductors (just pull one apart if you don't believe me). The impedance of a pair of wires is determined by their size (gage), the distance between them and the quality (dielectric contact) of the material inbetween. So, while the plastic is important, these cables fail at high frequencies because of the DISTANCE between conductors, which varies all over the place. Open up a SCSI 2 or 3 cable, what do you see? Ahhhh, twisted pairs!!! And the better the pairs (tighter impedance specs) the less the mismatch, the less the return loss, the greater the received signal strength, the less the bit errors. Flat cable can also help maintain impedance specs, at least better than just a bunch of loose wires. As frequencies go higher and higher, every dimension becomes more critical. Just take your car on a racetrack if you don't believe me. You need a race car? Buy a race car! You need a high-frequency cable? Buy one made, tested, verified, and guaranteed for whatever frequency band you wish. OK, class, how did I do? Steve Lampen Belden Electronics Division |
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Mark Wilkinson wrote in
news:wTt9b.467714$o%2.207687@sccrnsc02: In article ivn9b.463174$Ho3.74971@sccrnsc03, Lou Anschuetz says... (Nousaine) wrote in .net: Lou Anschuetz wrote: ...snips to specific content ..... So YOU hear speaker cables? Why not take a cable with 'sound' and compare it to zip cord in a bias controlled listening test and tell us what you find? Let me relate one extreme example. I used to use zip cord on my speakers (McCormack DNA 1 Deluxe to Apogee Slant 6). They sounded "OK." On the advice of many folks I purchased some moderately priced real speaker cables of the same length (and same gauge as it turns out). It turned out that with 2 different SPL meters there was a *measureable* difference. With the zip cord sound was down 6 dB below 50hz compared to high-end cable. I can reproduce this at will. Sorry, this just plain isn't possible -- unless you are telling me the "high-end cable" had a 6db attenuating high shelving filter, hinged somewhere around 50hz, built into it. I can't believe anyone would build such a gimmick. Please give more more info as to how you tested. Once again - I agree with you in principle. (I try to only cite weird examples since all others are dismissed ![]() Zip cord - same length as named-cable, same gauge as named-cable. Put on zip cord, walk down the frequencies with a test CD (the Stereophile works fine here). Using either A fast or C slow, see what (relative) dB ratings you see. This is *not* a cliff effect of course, but a gradual curve. As you lower the frequency, the dB ratings stay higher with the named cable (in both A & C, but varying in amounts). Test again as this cannot be possible (I agree). Same thing. I'm not so foolish as to believe there is something other worldly going on - but there is some reactance to the stranded zip cable (now serving duty quite nicely as extension cords ![]() Maybe it's a flaw in the zip cords (my preferred explanation actually) but the effect happens. This absolutely comes back to what I've said repeatedly, there is a "house" sound to speaker cables that is probably not due to some magic engineering, but either some flawed engineering or some error in manufacturing that is common from various cabling supply house. I tend to think such flaws more often than not are in material content and/or insulation properties. Certainly the named cable used twisting, while the zip cord does not. Maybe there is some EMI, RFI, EFI effect in my house that is undiagnosed. I'm told by many that these things should not effect the sound, but in this case something is clearly affecting the performance (even if not the sound). In my case maybe I'm just lucky to have picked a twisted pair speaker cable that happens to eliminate some effect. But, there is a reason why speaker cable folks do research (even if some of it results in bizarre unlikely explanations ![]() I'm betting though that such effects - even when much smaller - occur during testing and some design is implemented that by good fortune fixes the flaw. The problem is that we are looking to explain things when each individual item is small and out at an asymptote. Sales guys then jump in and latch on to some theoretical, if unlikely, explanation instead of letting the company admit that they found it by accident and folks seem to like it ![]() it is unexplicable - just sometimes difficult to explain. I'm willing to go through life allowing for things I don't understand - but am willing to learn about. -- Lou Anschuetz, Network Manager, CMU, ECE Dept. |
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It turned out that with 2 different SPL
meters there was a *measureable* difference. With the zip cord sound was down 6 dB below 50hz compared to high-end cable. I can reproduce this at will. This indicates a serious problem in either the measurement procedure or in your system somewhere. I'd suggest you spend some time looking for what the problem really is, rather than drawing conclusions that a cable change could cause it. I'd start by looking for something that moved in the room, causing the bass standing waves at your SPL meter to be different. Even not having your body in the same place for both measurements might do it. Or, what about a really bad connection in one of your cables, such as having only a couple of strands connected to do all the work - maybe you really compared a 12ga cable against a 28ga one :-) Try measuring the voltage at the speaker terminals for each wire. Does that show a severe difference? If not, the problem must be an acoustic one. If so, look for a very bad connection or a very unstable amplifier. Bob |
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Lou Anschuetz wrote:
Mark Wilkinson wrote in news:wTt9b.467714$o%2.207687@sccrnsc02: In article ivn9b.463174$Ho3.74971@sccrnsc03, Lou Anschuetz says... (Nousaine) wrote in t.net: Lou Anschuetz wrote: ...snips to specific content ..... So YOU hear speaker cables? Why not take a cable with 'sound' and compare it to zip cord in a bias controlled listening test and tell us what you find? Let me relate one extreme example. I used to use zip cord on my speakers (McCormack DNA 1 Deluxe to Apogee Slant 6). They sounded "OK." And...... On the advice of many folks I purchased some moderately priced real speaker cables of the same length (and same gauge as it turns out). It turned out that with 2 different SPL meters there was a *measureable* difference. "Real" speaker cable you say? What was 'unreal' about your original cable? With the zip cord sound was down 6 dB below 50hz compared to high-end cable. I can reproduce this at will. OK; how about the conditions under which you 'took' the measurements? Sorry, this just plain isn't possible -- unless you are telling me the "high-end cable" had a 6db attenuating high shelving filter, hinged somewhere around 50hz, built into it. I can't believe anyone would build such a gimmick. Please give more more info as to how you tested. Once again - I agree with you in principle. (I try to only cite weird examples since all others are dismissed ![]() What 'all others' have been dismissed? Zip cord - same length as named-cable, same gauge as named-cable. Put on zip cord, walk down the frequencies with a test CD (the Stereophile works fine here). Using either A fast or C slow, see what (relative) dB ratings you see. This is *not* a cliff effect of course, but a gradual curve. Tell us more; why not describe the full experimental conditions? As you lower the frequency, the dB ratings stay higher with the named cable (in both A & C, but varying in amounts). Test again as this cannot be possible (I agree). Same thing. I'm not so foolish as to believe there is something other worldly going on - but there is some reactance to the stranded zip cable (now serving duty quite nicely as extension cords ![]() Maybe it's a flaw in the zip cords (my preferred explanation actually) but the effect happens. It does? Why haven't others reported it? This absolutely comes back to what I've said repeatedly, there is a "house" sound to speaker cables that is probably not due to some magic engineering, but either some flawed engineering or some error in manufacturing that is common from various cabling supply house. Well what might be the 'cause?' That no supply house has been able to document? I tend to think such flaws more often than not are in material content and/or insulation properties. Certainly the named cable used twisting, while the zip cord does not. And you have no evidence except that you "tend to think" that "such flaws" are even extant? Now we're getting down to brass tacks. Maybe there is some EMI, RFI, EFI effect in my house that is undiagnosed. I'm told by many that these things should not effect the sound, but in this case something is clearly affecting the performance (even if not the sound). In my case maybe I'm just lucky to have picked a twisted pair speaker cable that happens to eliminate some effect. Eliminate "what" effect? But, there is a reason why speaker cable folks do research (even if some of it results in bizarre unlikely explanations ![]() There is no evidence that 'speaker cable folks' do any research. Please give me a link to any true listening research published by cable manufacturers. I'm betting though that such effects - even when much smaller - occur during testing and some design is implemented that by good fortune fixes the flaw. What "flaw?" The problem is that we are looking to explain things when each individual item is small and out at an asymptote. Sales guys then jump in and latch on to some theoretical, if unlikely, explanation instead of letting the company admit that they found it by accident and folks seem to like it ![]() Please; But, being unable to explain it doesn't mean it is unexplicable - just sometimes difficult to explain. Or replicate under bias controlled conditions ....wouldn't you say? I'm willing to go through life allowing for things I don't understand - but am willing to learn about. -- Lou Anschuetz, Network Manager, CMU, ECE Dept. OK; but how much listening under bias-controlled conditions have you experienced? |
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Lou Anschuetz wrote in message news:v7J9b.474021$YN5.323102@sccrnsc01...
Mark Wilkinson wrote in news:wTt9b.467714$o%2.207687@sccrnsc02: In article ivn9b.463174$Ho3.74971@sccrnsc03, Lou Anschuetz says... (Nousaine) wrote in .net: Lou Anschuetz wrote: ...snips to specific content ..... So YOU hear speaker cables? Why not take a cable with 'sound' and compare it to zip cord in a bias controlled listening test and tell us what you find? Let me relate one extreme example. I used to use zip cord on my speakers (McCormack DNA 1 Deluxe to Apogee Slant 6). They sounded "OK." On the advice of many folks I purchased some moderately priced real speaker cables of the same length (and same gauge as it turns out). It turned out that with 2 different SPL meters there was a *measureable* difference. With the zip cord sound was down 6 dB below 50hz compared to high-end cable. I can reproduce this at will. Sorry, this just plain isn't possible -- unless you are telling me the "high-end cable" had a 6db attenuating high shelving filter, hinged somewhere around 50hz, built into it. I can't believe anyone would build such a gimmick. Please give more more info as to how you tested. Once again - I agree with you in principle. (I try to only cite weird examples since all others are dismissed ![]() Zip cord - same length as named-cable, same gauge as named-cable. Put on zip cord, walk down the frequencies with a test CD (the Stereophile works fine here). Using either A fast or C slow, see what (relative) dB ratings you see. This is *not* a cliff effect of course, but a gradual curve. As you lower the frequency, the dB ratings stay higher with the named cable (in both A & C, but varying in amounts). Test again as this cannot be possible (I agree). Same thing. I'm not so foolish as to believe there is something other worldly going on - but there is some reactance to the stranded zip cable (now serving duty quite nicely as extension cords ![]() Maybe it's a flaw in the zip cords (my preferred explanation actually) but the effect happens. This absolutely comes back to what I've said repeatedly, there is a "house" sound to speaker cables that is probably not due to some magic engineering, but either some flawed engineering or some error in manufacturing that is common from various cabling supply house. I tend to think such flaws more often than not are in material content and/or insulation properties. Certainly the named cable used twisting, while the zip cord does not. Maybe there is some EMI, RFI, EFI effect in my house that is undiagnosed. I'm told by many that these things should not effect the sound, but in this case something is clearly affecting the performance (even if not the sound). In my case maybe I'm just lucky to have picked a twisted pair speaker cable that happens to eliminate some effect. But, there is a reason why speaker cable folks do research (even if some of it results in bizarre unlikely explanations ![]() I'm betting though that such effects - even when much smaller - occur during testing and some design is implemented that by good fortune fixes the flaw. The problem is that we are looking to explain things when each individual item is small and out at an asymptote. Sales guys then jump in and latch on to some theoretical, if unlikely, explanation instead of letting the company admit that they found it by accident and folks seem to like it ![]() it is unexplicable - just sometimes difficult to explain. I'm willing to go through life allowing for things I don't understand - but am willing to learn about. You 'have to know' your measurement was/is bogus, IMO, Bob's comments are right on -- time to enter troubleshooting mode. Get a tripod for the Ratshack meter. Get a good voltmeter. Figure out what's screwed up-- it's not reactance in the zipcord or something similar -- it's just a bad test or bad equipment. Just trying to help. |
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