The best cables use air dielectrics, IMO. All solid dielectrics will color the sound in some way.
cable dielectric cause of artificial sound
Hi folks, I would like to know what your opinion is about the following issue. About 90% of high-end cable manufacturers use PTFE as dielectric. Many of their cables sound much alike and they have a few of these characteristics in common: clean, relaxed and laid back sound but at the same time very dynamic (though a bit artificially), very quiet ("black background"), very good (also artificially) left/right separation. But I think albeit these traits, they tend to sound "technicolored", "sterile" and unengaging (lacking PRaT also). Some cable manufacturers are using bleached cotton as dielectric. These cables sound different: they have more natural dynamics, a mellower sound, more intimate soundstage, more tonal colors and so on. Are these differences mainly due to the dielectric material used? Why is for so many manufacturers PTFE still the ultimate dielectric for the use in audio cables?
Chris
Chris
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There are many factors other than just dielectric that affect cable sound. Geometry and the use of shielding have a greater impact on sound quality than dielectric, IMO. I've heard excellent cables that employ teflon, polyethylene or foamed PE. I suspect that many cable manufacturers feel they must use teflon insulation to be considered 'serious'. |
I stumbled across a very curious phenomena pertaining to cable dielectric at work the other day. Nobody that i have discussed the matter with can explain what is happening, yet they have seen the very easily measured and duplicated results that i'm obtaining and can't deny them. I have ideas as to what is causing this curious phenomena, but don't want to speak up about this as of yet. I will say that what i'm seeing tends to make me believe that dielectrics, which aren't supposed to conduct, have a polarity / directionality to them i.e. they conduct better in one direction than in another. I know that some companies already have cabling on the market that supposedly deals with this subject, but i don't think that they fully understand exactly what is going on here. I just hope that Clark Johnsen doesn't see this. Something about polarity based issues tends to get him in all worked up : ) Sean > |
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Dazzdax: I would not doubt that Audioquest's "DBS" system is based on something similar to what i'm experiencing. Without talking to Bill Low, i'm strictly guessing at that though... Tplavas: I was working with standard "foam" dielectric as found in typical RF based coaxial cables. While the exact dielectric make-up will vary from manufacturer to manufacturer, they are probably pretty close. How much this applies to audio based cabling, with many actually using RF based coaxial designs as their core, is beyond me. Given that my testing was conducted within the AF band, i would have to assume that the basic results would apply to audio cabling to at least some extent. Whether or not i want to fully dig into this area is a decision i'll have to think about. Sean > |
Sean, As far as the AQ DBS system, it definitely does 'something'. I'll leave judgement about it's effects aside for now, since I have experienced the 'effect' on one AQ model only, but I found recently that the DBS system does have an effect on the cable to which it's attached. I had previously owned two 1 meter long AQ Eagle Eye digital cables which I was using from my transport to DSP, and from the DSP to my digital crossover. Having heard some positive improvements in the past by using .5 meter digital cables (I know, I know, shame on me for breaking the "rule"),after contacting Audioquest and confirming that they would make .5 meter digital cables, I ordered two .5 meter AQ Eagle Eye cables through an AQ dealer, who told me they would have to be special-ordered from AQ, who would make them in that length, and then drop-ship them to me. To make a long story short,when I received the cables and plugged them in, I thought I'd made a huge mistake by buying the .5 meter Eagle Eyes. Instead of revealing more detail and dynamics as I'd expected from prior experience, they were slow, bloated in the bass, and lacking the kind of top-octave extension I was used to from the 1 meter Eagle Eyes. Thinking they needed to break-in, but not really expecting them to ever change enough to be acceptable, I put them back in their boxes, and didn't touch them for about 3 weeks. When I plugged them back in so I could begin 'burning' them in, I gave them a quick listen to confirm my earlier evaluation. HOLY COW...what a difference!!! 3 weeks of sitting untouched in the box and they'd transformed into tight, revealing, highly-textured digital cables. Since I'd made no other changes to my main system in that time, I can only attribute the huge change to the "charging" of the dielectrics in the DBS field over the 3 weeks they went unused. Apparently the only way to really hear the effect of the DBS system is to listen to newly-manufactured cables, and then wait a few weeks and listen again. |
I agree with Tplavas. The cable geometry makes more of a difference in sound than dielectric types (if we're just counting the big 3: Teflon/PTFE, Polyethylene, cotton). Air is the best dielectric but difficult to manufacture successfully because copper will oxidize over time when exposed to air. Manufactures feel it necessary to use PTFE because it's considered among the best solid dielectric, they can't charge a high price for an inferior insulator such as PVC. Geometry such as multiple conductor braids, litz, effect the sound drastically. In my experience, a cable with high inductance will yield a sound that is smoother/warmer. |
Elizabeth, Chris VenHaus of VH Audio sells a 28 gauge solid core silver wire that's insulated with four layers of cotton serve and has a very uniform outside diameter which would make it very good for twisted pairs or, my preference, braided quads. It's $59.99 for a 25 foot spool. se |
I think people freak out too much about copper wire oxidizing. Unless it's oxidation between mechanical contacts, I haven't found it to be any problem at all. It's only a few molecules thick and I find that much more preferable to a whole hell of a lot more plastic extruded over the wire. Even the thinnest enameling is orders of magnitude thicker. Some say copper oxide isn't very conductive. Yeah? So what? Teflon isn't very conductive either. Nor the air surrounding the wire. Essentially all the oxide is doing is effectively reducing the diameter of the wire by a few molecules, which is nothing compared to the variation of wire diameter due to manufacturing tolerances. se |
Agree, audiophiles are often too critical with minor details, but oxidation which occurs at the surface of a conductor must be taken seriously. Electrical signal tends to travel at the surface of a conductor, NOT the center of a conductor as some may think. One example is the conductor designed by Analysis Plus, they design a conductor which is hollow in the center. Allowing the surface of a conductor to oxidize over time will change the character of the cable and shorten cable life. Oxidation is a reason why air dielectric is not used more often. Scar |
Agree, audiophiles are often too critical with minor details, but oxidation which occurs at the surface of a conductor must be taken seriously. Electrical signal tends to travel at the surface of a conductor, NOT the center of a conductor as some may think. It's not so bad as you portray. At audio frequencies the signal current flows through the entire cross section of the conductor, with increasing current density as you move out radially from the center. The difference between the current density at the center and that out toward the surface depends on frequency and the diameter of the conductor. But so what? As I said previously, all the oxide layer does is effectively reduce the diameter of the conductor by a microscopic amount. This will also reduce its cross sectional area which will have the effect of moving a tad more current toward the center of the conductor and ultimately reduce the effect you're speaking of here. In other words, the current density throughout the cross section will be very slightly more uniform than it would have been otherwise. One example is the conductor designed by Analysis Plus, they design a conductor which is hollow in the center. Sure, that's one approach. Or you can just use smaller diameter conductors. The smaller the diameter of the conductor, the more uniform the current distribution through its cross section will be for a given frequency. Allowing the surface of a conductor to oxidize over time will change the character of the cable and shorten cable life. Don't see how it would change the character of the cable in any significant way or shorten cable life. Soon as copper is exposed to the air, it soon gets a surface layer of oxidation. This layer of oxidation actually works to prevent further oxidation Hell, I have a couple of spools of bare copper wire here that are probably going on 40 years old. Still in good shape. Oxidation is a reason why air dielectric is not used more often. I would disagree. But if the reason is oxidation, I'd say it's because people tend to irrationally freak out about it just because they've been told by someone that they should freak out about it se |
Steve, In the world of audiophile where isolation cones, cable lifters, contact enhancers are used, a oxidized conductor would not go over well. Audiophiles will pay hundreds to thousands for a pair of cable where copper used are of 5 nines to 6 nines in purity, what's the the use of buying this quality if oxidation is not controlled by the designer. Oxidation shorten the life of a cable when it sound characteristic is changed due to oxidation, yes it does sound different. I don't mean it's life is shorten because it no longer work. Your spools of bare copper wire laying around will probaly work for another 40 years, but the quality and sound won't be the same. Keep in mind, this thread started as differences between dielectric, so people are extremely critical with the slightest change. Rja, Cotton dielectric sound slightly less analytical than Teflon, but the ultimate is still the geometry of the cable. Partsconnexion is another place to buy cotton dielectric wire. Scar |
I have to throw in with Steve, and agree that surface oxidation is not necessarily something to be afraid of. It's important to remember that most wire used in audio is annealed, and annealing takes place at high temperatures, which can cause functionally significant oxidation within seconds. However, this can be controlled somewhat by manipulating available oxygen levels and cooling times. When considering stranded wire, such as that used in speaker wire and power cables, a small amount of surface oxidation can actually reduce the negative effects of strand interaction and eddy currents, without the higher dielectric losses seen with strand coatings. Tim LeVasseur Audio |
Several cable manufacturers are using cotton dielectric. Has anyone identified a sonic signature for cotton compared to PTFE? I'm not much of a "sonic signature" kind of guy, but I do prefer cotton over plastics, including PTFE. And ultimatley prefer silk over cotton. One thing worth noting though is that the dielectric constant given for cotton, saying it's even lower than Teflon, is somewhat misleading. The figure that's given (1.3 to 1.4) is for cotton in its raw form, i.e. balls. In its textile form, i.e. woven into thread and fabric, is higher and more akin to that of silk at 2.5 to 3.5. So for those who are obsessed with numbers, unless you string your wire through a bunch of cotton balls, you're not going to get that 1.3 to 1.4 dielectric constant. Reference Audio Mods sells braided cotton sleeving in various sizes and vt4c.com over in Hong Kong sells braided silk sleeving (as well as cotton). And as I mentioned previously, VH Audio sells a 28 gauge solid silver wire with a quad serve of cotton insulation (serve means it's wrapped directly around the wire rather than being a braided sleeving). se |
Scar, I am afraid I agree with a lot of what Steve says. Below is a post with 2 links in it I suggust you read. http://forum.audiogon.com/cgi-bin/fr.pl?cspkr&1160450950&openmine&zzArtizen65&4&5#Artizen65 What you are refering to is skin effect. Now in my training 100mhz and above is where skin effect really starts to matter. In the link above it deals with skin effect in the audible frequency range. Now I have been told by an EE friend of mine that it is a weak proof. Not that I now necessarly agree with him at this point in my life strictly from a theoretical stand point not a mathimatical one. If you start at 1hz the electrons use the whole wire as the frequency increases the electrons migrate to the outside of the conductor. It is not untill your reach the upper frequency's that you actually get into the skin effect theory. It is at these frequencies that the dialectric becomes more of a factor as the electron interaction between the conductor and dialectric becomes more acute. It is at this point where I might disagree with Steve from a theoretical standpoint. Oxidation will decrease the interaction between the conductor and dialectric and could possibly affect the upper frequency range of the cable. This could have a positive affect or a negitive affect it depends on the frequency and the level of oxidation and or corrosion. IMHO in the lower frequencies it should have no affect at all. Three major things things come into play with the conductor, material used, purity and quality of the extrusion. Imperfections in the conductor be it purity or vairing raidi of the conductor will affect electron flow through the wire. This will have more of an effect at higher frequencies than at lower frequencies. Silver has a slightly higher frequency response than copper in the 20hz to 20khz range. Hence why some people perceive silver as being brighter than copper. So lets assume that skin effect exists in the upper frequency range of the audible band 20hz to 20khz. Other than preventing corrosion or oxidation of the conductor the dialectric should be selected for minimum interaction with the electrons in the conductor. It is this reason that air is the best dialectric. It by nature attracts the fewest electrons from the dialectric or has the least negitive impact by passing stray electrons to the dialectric which allows the electrical signal to stay more completly in-tact as it travels down the conductor. Keep in mind this has a lot more affect in the upper frequencies than the lower frequencies. Ok I am all tapped out for now although there is more I suggust you read the two links posted in the other thread. There is also a paper on the same site about wire topology. |
Scar In the world of audiophile where isolation cones, cable lifters, contact enhancers are used, a oxidized conductor would not go over well. Then I guess it's good that I only worry about what works best for me. Oxidation shorten the life of a cable when it sound characteristic is changed due to oxidation, yes it does sound different. Well, given that placing photographs of yourself in your freezer will make your system "sound different," you'll forgive me if I don't consider "sound different" to be of much worth with regard to issues such as the actual physical properties of a cable. Now, if you could state what the actual change is and how it manifests itself in the signal, that would be helpful. Your spools of bare copper wire laying around will probaly work for another 40 years, but the quality and sound won't be the same. Ok, but why exactly would that be the case? What exactly changes beyond what I had said previously that the effective diameter of the wire is a few molecules smaller? se |
Artizen65 Silver has a slightly higher frequency response than copper in the 20hz to 20khz range. Hence why some people perceive silver as being brighter than copper. This doesn't make sense. Silver being slightly more conductive than copper will mean that skin effect will be slightly worse in a silver conductor than a copper conductor, all else being equal, and therefore have a slightly reduced high frequency response compared to copper. So lets assume that skin effect exists in the upper frequency range of the audible band 20hz to 20khz. Other than preventing corrosion or oxidation of the conductor the dialectric should be selected for minimum interaction with the electrons in the conductor. It is this reason that air is the best dialectric. It's not the electrons that the dielectric interacts with, at least not directly. It's the electric field that the dielectric interacts with. se |
Sean The dielectric becomes more conductive / lossy over a period of time. As such, the electrons DO interact with the dielectric, both in terms of conductivity and magnetic field. The measurements that i mentioned above pertain directly to this subject. Well, since you didn't provide any information whatsoever about your measurements, there's no way to evaluate your claim. se |
Steve, It seems our point of view is different, you're looking at it from the technical side, mine is from an audiophile talking about audiophile cable. Some of you sound like many of the electrical types I've talked to where everything has to be proven with numbers and measurements. These people will never believe two audio cable can sound different because it can't be measured. Audio cable is NOT and never an exact science, I repeat NOT. While skin affect does occur at frequencies above 20khz, differences can still be heard. High End cable designers don't come up with a design so that their cable will only sound as they intend after oxidation has occured, they do their best to limit oxidation with the use of Teflon & PE, this is why we don't see many exposed copper in high end cable design. Many cable brand has it's signature sound, for example the consistent smoothness of Cardas cables, if they don't limit oxidation after a short period of time highs will be affected and the sound is not as George Cardas intended to be. My point of all this rambling is, oxidation has to be taken seriously in a high end cable because the signature sound that the designer intended will be no longer be after corrosion occurs. I don't think audiophiles want to spend hundreds to thousands of dollars on a corroded cable anyway. Dazzdax, Sorry we hijacked your thread with all this rambling. It's what makes discussion fun! Scar |
Tgrisham If the issue is that the dialectric potentially changes the sound, and oxidation of copper potentially changes the sound, wouldn't pure copper wire covered in something to prevent shorting, and oxidation, be ideal? Ideal? I dunno. That rather presupposes that if the sound is in fact to be changed, it must be a change for the worse. Is this all really just a numbers game when you get to the bottom of it? I've always found it curious that often the same people who think that a SET tube amp, with horrendous amounts of distortion, high output impedance, limited frequency response, etc. sounds absolutely fantastic, but when it comes to something like wire, everything changes. The wire needs to be the most conductive. It must be of the highest purity. The dielectric constant of the insulation must be as close to 1 as possible. Just seems a bit schizophrenic to me. se |
I can't help but laugh at all the measurement techno-jumbo talk and electrical training with facts to back it up talk going on in an audiophile forum, this hobby is the farest thing from best measurement equal best product. Why do we even talk about spending hundreds of dollars on an audio cable when a $10 interconnect from Wal-Mart measure much better. The capacitance, resistant, inductance numbers of the most respected audiophile cable brands out there such as Kimber, Cardas, XLO, etc. consistently measured worse than some .25¢ coaxial found at the local hardware store. How can an audiophile spend hundred of dollars on a wire and corrosion is not even important? hope someone here agrees with me... Why do so many love tube amps when a solid state has much less measured distortion? it's never been about the technical side people. Cardas and Kimber cable measurements are in the same ballpark, why do they sound so different? Audiophiles are the ones who hear the difference and believe, engineers are the ones who believe the numbers and never hears. Scar |
Scar972 It seems our point of view is different, you're looking at it from the technical side, mine is from an audiophile talking about audiophile cable. I don't know what that means, "an audiophile talking about audiophile cable." You have made a number of objective claims of fact, none of which have been substantiated with any sort of objective evidence or proof. Some of you sound like many of the electrical types I've talked to where everything has to be proven with numbers and measurements. Well, when one makes objective claims of fact, the substantiation of those claims must also be objective. If you have no objective substantiation for your objective claims, then you're doing little more than trying to pass off opinion as fact. Is that what it means to be an "audiophile talking about audiophile cable"? To pass opinion off as fact? These people will never believe two audio cable can sound different because it can't be measured. It has nothing to do with whether it can be measured. It has to do with first establishing that there is in fact an actual audible difference between them. Audio cable is NOT and never an exact science, I repeat NOT. While skin affect does occur at frequencies above 20khz, differences can still be heard. And here is yet another objective claim of fact. When exactly was this established as fact? High End cable designers don't come up with a design so that their cable will only sound as they intend after oxidation has occured, they do their best to limit oxidation with the use of Teflon & PE, this is why we don't see many exposed copper in high end cable design. How do you know this is necessarily the case? How do you know they don't do it simply because many people have been prejudiced against it by people trying to pass off opinion as fact? My point of all this rambling is, oxidation has to be taken seriously in a high end cable because the signature sound that the designer intended will be no longer be after corrosion occurs. I don't think audiophiles want to spend hundreds to thousands of dollars on a corroded cable anyway. Now here you are spouting off while demonstrating you don't even know what you're talking about. First, oxidation and corrosion are not one and the same. Corrosion is a two part process that requires both oxidation and reduction, where material is actually lost. Copper actually RESISTS corrosion. This is what gives it such high value in applications such as roofing material and water pipes. As I said in a previous post, the microscopically thin film of oxidation that quickly forms on the surface when it's exposed to air actually acts as a protective barrier against both further oxidation and corrosion. So please, before you go trying to scare people about "corroded cable," get your facts straight. se |
Steve, Tell me how am I suppose to prove an oxidized conductor sound different from a new conductor in words? Do I need to invite you over so we can compare the two for audible differences. As I stated in previous post that audible differences in analog interconnects cannot be measured, only can be heard, so if you need technical data, and graphs, I don't have them, so this discussion comes to a close. You ask me to establish that there is in fact an actual audible difference. In order to established that two interconnect can sound different as a fact, you just need to compare two interconnect of different geometry such as a litz design and a single conductor design with small guage and hear for yourself. Same goes for digital interconnect, two can sound different eventhough it's just passing 0's and 1's from one component to another. You can call my claims as just opinion, but to me they are facts based on the years I've spent DIYing different cable geometry and experiences with different conductors and dielectrics. If there wasn't a difference we would not get all these people on forums asking for opinions on cables. Scar |
Corrosion of a conductor can take place due to oxidation, thermal shifts and / or a chemical reaction. Due to the fact that many conductors are directly in contact with a chemically formulated material ( dielectric ) that is exposed to electro-mechanically induced voltages, vibrations and thermal shifts, it is quite possible for the conductor to become corroded within the cable jacket itself. This is due to the chemical make up of the the dielectric breaking down ( due to any of the aforementioned reasons ) and leaching onto the conductors. This is part of what i was discussing above i.e. cables changing sonics / electrical characteristics over time due to internal decay. Scar: You are wasting your time trying to have a meaningful conversation with this individual. Been there, done that, won't go there anymore. Learned my lesson, as have many others in several different forums. That could be why this party has finally migrated over here i.e. he's running out of other people's sandboxes to dump in. Sean > |
in the latest absolute sound krell founder Dan D'Rgostino talks about how he determines that something will sound good. "I like to see waveforms come out the way they look at the imput". why is cable any different? i have a relativly expensive system with a lot of the krell equipment along an extensive vinyl setup. i have listen to some very expensive wire in my system and am hard pressed to hear any real difference. i thought cables were the final thing to make everything sound better to bing it all together, but infact, they seem to be the least important part of my system. to many get cought up in the hype instead of simple common sence. |
I like Koegz response. After spending all this money on electronics, we expect wire to be the final touch. Wire is like horsepower, to get more horsepower costs money, to get a lot more horsepower costs huge amounts of money. You have to have great resolution in a system to even hear the subtle differences in wire. But, rather than argue on the forums, maybe we should all go listen to more music??? This is like politics, we will never change each other's minds about wire! |
A couple of points: Annealed cables are often annealed in an oxygen free atmosphere (dry nitrogen) specifically to prevent surface oxidation. Many oxidants are semiconductors and may even exhibit diode like effects(remember selenium plate rectifiers?), I think metal oxides in cables are just plain bad news. Gauge and metalurgy make a difference to my ears, but dielectric absorbtion seems to be the largest contributor to hard or edgy sounds from cables. I've made my own using foamed Teflon as a core (more air, less plastic) they sound very clean but not as warm as the better (read expensive) commercial cables. The differences in sound are subtle and the more revealing the system the easier they become to hear. I have not had the experience of being able to hear differences between interconnects on any mass market equipment. i.e. at least some nay sayers will not in fact hear any interconnect differences on their systems because the cables are not the weakest link. I think almost any system will display speaker wire sonic differences between copper and steel alloy wire (cheap commercial wire, the steel prevents stretch) and a pure copper wire. These differences do not appear to be subtle. |
After watching this thread with great interest, the impression I get after it rising and now cooling off is that we STILL know very little about high end audio cabling. I've seen folks of all manner of approaches and background have theories, but no real knowledge. By this, I don't mean to offend, just that my definition of knowledge is something on a higher plane that what I am reading. So far, only "I've seen this", "I hear this", or "I tested that". Yet, day after day I read how this cable sounds too dull in system A, while another member disagrees, saying it drove his ears to bleed. Does surface oxidation exhibit a detrimental effect on a wire or not? Doesn't seem as if we're sure - some say yes and some no, both being just as emphatic as the other. Are those who feel cable geometry trumps all other factors (material, insulation, etc.) the ones who have the real answer??? And, as far as the point of the thread, what do we really know about the effect of a dielectric on things? Is teflon necessarily better than PVC, polyethylene, polyester, kapton, or polypropylene? For at least a decade now, we have been voting yes with our wallets because that is the conventional wisdom, not because we "know" it's true. What about PVDF (Kynar), which has probably the highest dielectric constant of any stable polymer I can think of. How do cotton and silk rate in absolute terms? Why not think about acrylic or wool? If air is truly superior, while oxidation is to be avoided (for the sake of argument, again, I have no true idea how critical it is), the cost of filling a tube with a gas such as nitrogen (the main component of air apart from oxygen), argon, helium, or whatever to protect the copper from oxidizing is not very expensive whatsoever. After all, they used a ton of nitrogen (or, possibly, 5% hydrogen in 95% nitrogen - forming gas, which is used in a reduction furnace) to anneal the wire, correct? And, I have yet to touch on copper, silver, gold, alloys of all manner of metals (for example, 55% palladium/45% silver - the most stable conductor in terms of temperature coefficient of resistance, environmental degradation, and the like), aluminum, carbon... Hopefully, JD's (Jadem6) thread will spur additional research into the subject. His has been the most valuable thread I have seen here in any audio discussion forum in years. It's certainly got me thinking of cable in a very big way. In my view, we should have come to definitive answers long ago. Not to seem as if I am on a high horse as I've also done just about nothing to advance the craft. Wish I was still a chemist/material scientist in many regards because I know I would devote a substantial part of my time researching all manner of variables. Wire remains more or less black magic. Not because it is, but due to our fundamental lack of understanding of the subject. Unfortunately, there doesn't seem to have been much in the way of research since the late 1990s. There's certainly no impetus for it, as we're mostly served by ultra niche companies run by folks without the knowledge, training, or money to conduct it, who are making big profit doing things as they are doing them. Why change? WE certainly aren't demanding it. As much of a subjectivist as I am, there is a downside to such thinking being so pervasive in this hobby. We are, more or less, simply at the mercy of swapping products in and out of our systems, not knowing how they will sound. We probably should be at the point where we say this cable will tame brightness, and this one will give you a bit more bass impact and on and on. And, because we truly do not understand why one cable sounds better than another we are apt to pay hundreds and thousands of dollars for products that can often be bought for pennies and dollars. The end result being far more consuming of time and money than it probably should be. |
IMO, there will never be a perfect analog cable. Cable construction variables and system interfaces will always result in some sort of coloration. With digital HDMI interfaces progressing, we no longer need worry about analog cables. In that case, any cheap cable will suffice. As an audiophile junky I will dismiss what I just wrote. |
Trelja, I don't think we can underestimate the confusion sewn by the cable industry itself. When some cable designers claim that cable "x" in their lineup is more detailed than cable "z" because of some proprietary treatment or improved dielectric, when if fact they've also changed the geometry of cable "x" (but don't mention it), they just add to the confusion of listeners who are lead to think the sonic change is caused by factors that may have very little sonic impact compared to geometry. JMO. |
recently i went to radio shack and bought microphone cables which come with balanced ends. installed where resently i was using synergistic balanced. tell you what they sound great tight bass smooth mid and high end. very natural. then i used them on my sub where i was using single ended cables, sub never sounded better very tight and deep bass i am blown away. i have a talon rock sub 1000 watt. the balanced cables made a big diff over single end. very satified. |
!!!Transmission line theory does not apply at audio frequencies, unless your cable is a minimum of 500 feet long, and even then this is at 100 kHz and 1/10th a wavelength!!! There is no debating this, not b/c I mention it, but b/c this is physical reality. Some cable vendors would have you believe that characteristic impedance actually matters at audio bandwidth (do i hear any ee's in the Audience?). What total rubbish. However, any given cable, coax, twin, twisted pair, will indeed have a characteristic impedance (this is purely a function of geometry and is nothing more than the ratio of voltage to current along the line). This (Znot), however only becomes relevant when the cable length is longer than a fraction (usually 1/4 lambda) of the transmitted signal's frequency. The signal frequencies passing through analog interconnects and speaker cables are effectively DC b/c the wavelengths are so long. All this yak about characteristic impedance, load matching, and dielectric loss tangents (aka dissipation factor) applied to cable in the audio band is akin to applying special relativity when describing the point at which two cars will intersect on the highway (unless your car is a super hopped up red civic with a really fat tailpipe and has a mighty rocket engine), when good old distance = rate x time works perfectly every time.... I am not trying to disagree with anyone, and I did not invent TL theory, i'm just chiming in to remind, or point out, that all this talk about transmission line theory (dielectrics/insulation having appreciable influence beyond stopping our conductors from shorting out) just is not reasonable at analog audio frequencies. I do think it is possible for such an ill designed cable to hit the streets such that it's basic RLC can affect the signal, but this is different than transmission line issues. This type of cable might even have a coloration some find pleasant in their system. for a real interesting (if you are participating in this thread I assume you are interested) and downright truthful (no bs) discussion of the matter check out: http://www.audioholics.com/techtips/audioprinciples/interconnects/DielectricAbsorption.php |
Dpac996: You and Audioholics are absolutely right!!! I recant all of my previous statements, experiences and chalk it up to my ignorance of the "facts". Thanks for clearing all of this up for me. Helping me to understand that all cables of reasonable construction and parts quality sound identical will make my life ( and maybe even yours ) SOOOOO much better. Sean > |
All this yak about characteristic impedance, load matching, and dielectric loss tangents (aka dissipation factor) applied to cable in the audio band is akin to applying special relativity when describing the point at which two cars will intersect on the highwayTssk, tsk, Dpac996, really:). What the audioholics article is/should be really implying is, for example, that connections are critical for, say RF (i.e. it simply won't work) and uncritical for audio frequencies (i.e. it WILL work -- but perhaps badly, i.e. with high losses and noise introduction). Unfortunately, if you use a 50ohm cable on 75ohm connection you'll have reflections even at audio freq; if you create a highly capacitive interconnection, you may get oscillation, and will probably get attenaution of frequencies, even at audio frequencies; if you use additional conductors (say for shielding) you will change the electrical charactersitics of your connection and introduce shifts in the transmission; simple: if you use a thin conductor you introduce a higher resistance than with a thicker wire, and possible phase shift in lower frequencies vs higher frequencies -- even in the audible range (try it, it works!). Etc, ad nauseam. If I remember correctly, Sean works in RF applications, hence his comment: Helping me to understand that all cables of reasonable construction and parts quality sound identical will make my life(...) SOOOOO much better. How nice that would be! |
Sean: 0"What the audioholics article is/should be really implying is, for example, that connections are critical for, say RF (i.e. it simply won't work) and uncritical for audio frequencies (i.e. it WILL work -- but perhaps badly, i.e. with high losses and noise introduction)." THis is what you are saying. That article simply points out that dielectric loss tangents/DF are meaningless at audio band frequencies. It's not that an audio connection is uncritical, it's just unnecessary to view it like an RF transmission line. A ~50 kHz signal has a wavelength of 1000's of meters (lambda = propV / f ). Please someone, explain to me why anyone thinks this scenario should be treated the same as one where the conductor length itself is at or bigger than the wavelengths traveling on it. That is why it's effectively DC (from a tl standpoint) on a wire of typical home cable lenghts. "Helping me to understand that all cables of reasonable construction and parts quality sound identical" 1)I was trying to say that all cables do not sound the same b/c of , say reflections (vswr higher than 1), but rather lumped (rlc) chraracteristics. Inductnace and mutual inductance are based on geometry and small changes may manifest in different "sounding" (i think more like filtering) cables. Gregm: 1"Unfortunately, if you use a 50ohm cable on 75ohm connection you'll have reflections even at audio freq" Hmmm are you sure about this? please show me the article or data you have. Perhaps I am missing something 2"if you create a highly capacitive interconnection, you may get oscillation, and will probably get attenaution of frequencies, even at audio frequencies" im with you on that. This has nothing to do with TL theory, this is basic lumped circuit analysis of the RLC. Excessive capacitcane can make sources with high output Z unstable. No big deal. Once again the attenuation is due to 1st order RC filter. Not dielectric absorption or mistmatch 3"if you use additional conductors (say for shielding) you will change the electrical charactersitics of your connection and introduce shifts in the transmission;" I think your partly right: you will add inductance. yes this changes the lumped characteristics. Any filter causes phase shifts but don't confuse this with V/I lag due to VSWR (voltage standing wave ratio). 4"simple: if you use a thin conductor you introduce a higher resistance than with a thicker wire, and possible phase shift in lower frequencies vs higher frequencies -- even in the audible range (try it, it works!)." Once again you are describing the RLC componenets of a cable. I agree that changing these will change the sound. Again this is not due to inherent mismatch b/t cable and source or sink. We should not confuse source output impedance and sink input impedance with characteristic impedance as it applies in RF (freq >>100kHz) signal transfer. And dudes: I am not trying to pick arguments with anyone. I am not the one who invented the theory. I am trying to relay the facts as i understand them. I sure might get confused myself in the description of them ( i try not but it's early and the java is empty) but they are out there for all to see. I am not a "measurement type" or one who sucks the life out of audio enjoyment. I just like to stick to the facts and separate myself from the rampant bullshit from marketing departments. |
please show me the article or data you have. Perhaps I am missing somethingWhy on earth do you need an article or "data" or any other, further erudition? You might measure it, if you wish -- but better still, don't bother:) What may usually happen is noise pick up. And no, you're not missing anything :) IMO it's not a matter of crucial importance... I just like to stick to the facts and separate myself from the rampant bullshit from marketing departments.With you, 100%. You must admit though, sometimes they are very creative. Cheers |
Dpac: One can pick and choose as to what they think matters at audio frequencies, but the bottom line is that Audioholics believe and teach that all reasonably well constructed cables sound the same. Since we know that all cables don't sound the same and / or provide consistent results under various types of installation conditions, all of their math equations obviously don't cover / explain all of the various aspects that alter cable / component interaction and system sonics. I'm not just picking on Audioholics, but all of those that blindly spout the same "cables are cables are cables" dogma. As far as using smaller / larger conductors changing the sound of an interconnect, most cables terminate into a component that has an impedance that is hundreds to thousands of ohms higher than the series resistance of the cable. As such, changing the series resistance by even an ohm ( a LOT for a reasonable length cable ) via altering conductor size becomes a moot point. Please remove that factor from your arsenal of responses. The fact that tonal balance and high frequency resolution, which is attributable to skin effect, are directly altered by changing conductor size, doesn't seem to phase them. One can build identical cables with the same nominal LCR, grades of conductors, grades of dielectric, grades of connectors, etc... with the only variable being conductor size and hear the audible differences. The fact that Audioholics profess that skin effect does NOT come into play at audio frequencies what so ever makes me want to disregard their findings all together. No matter how much math one does, you can't explain away things that are really happening. When theory doesn't fit reality, which one is wrong??? As far as your comments go about shielding, this typicaly adds capacitance, not inductance. It can also change the velocity of propogation, depending on how the shielding is implimented. In doing so, it effectively changes the path length and loading characteristics that the source component sees, following some of the same principles that apply to transmission line theory. I'm not saying that audio cables work the same as RF cables, but that many of the same principles can be applied. I also think that, because people like Audioholics / believers in archaic dogma have been conducting most of the testing in this area, we don't have many of the answers that might have otherwise already been explained. Thinking within the box only lets one see what is in the box. Obviously, the variable results that occur under many different situations of cable / component interaction are OUTSIDE of the box, negating that line of thinking. As such, it leads to limited conclusions and possibilities, hence the problem with the theory not always fitting reality. Sean > |
I have very great doubts that the RF Transmission line theory that Sean promotes has any relevance to audio. He couldn't convince me with all his words. But then he did something simple...loaned me a couple of speaker cables which I compared with zip cord. That won him the debate. The difference was not nearly as dramatic as some advocates of fancy wire claim, but there was something there. I still doubt his theories, but I went out and bought some speaker cables. |
Dpac, Since you seem to be into math and proofs I suggust you read this. http://www.st-andrews.ac.uk/~jcgl/Scots_Guide/audio/skineffect/page1.html I was going to stay out of this thread after my initial post but it appears that like Sean said one must think outside the box. Remember there are 3 basic theories electron flow, hole flow and transfer of potential. Which of these theories applies depends on when and where you went to school. You need to read my previous post and the link. And as for credentials mine are not as impressive as some others on this site. 7.5 years as a Navy electronic technican. Schooling is the equivelant of an AS EE degree. 7.5 years as a digital switch design engineer. Dpac electronics is PFM period. As an example there was a 100 Mhz reference oscilator in a spectram analizer providing 200 Mhz out of the calibration output. With 4 amplifer stages off of the oscilator. The analizer worked fine in all respects. The problem was a cracked base biasing resistor for the 4 amplifer stages which was in the crystal oscilator circuit. If you can tell me why I might give you knowledge some creedence. Because I already know why and it is not PFM. |
Hi ET, I wanted to post these comments, but please understand my motive is to educate, not criticize. Your magnet wire setup is simple in design and no doubt sounds cleaner without the shielding in most cable designs. It is not however because you have no dielectric, in fact the enamel coating on the wire you are using has a relatively high dielectric constant of 5.1. A bare wire in a vacuum would be a 1.0 and bare wire in air would be slightly higher. Cotton and dry paper have fairly low dielectric constants of 1.3 and 2.0 respectively. The problem with copper wire in air, cotton or paper is corrosion and oxidation. Cotton and paper will both retain moisture in a humid climate and actually speed up the oxidation process. This is where poly___ something and Teflon become so useful, but as discussed here, they carry a sonic signature with them. The solution of enamel coated copper wire seems so logical, but in fact it is not a great dielectric at all. Dielectric constant is a measure of the charge retention capacity of a medium. In general, low dielectric constants (i.e., cotton @ 1.3-1.4) result in a "fast" substrate while large dielectric constants (i.e., Alumina @ 10.0) result in a "slow" substrate. What this has to do with our audio industry is obvious. The lower the dielectric the less energy retention and the easier the signal is carried. For this reason copper in inherently limiting if we want to use low dielectric materials to isolate wires. In this respect a super thin poly__ something would actually be a better choice than enamel. The issue then becomes finding a super thin covering on copper wire. This is not as easy as one might think, but there are thin tubing that can be shrink wrapped to a bare wire that may prove to be an excellent choice over enamel. So I suspect the real reason you are happy with the sound of your system is two fold, first the fact that the wires are allowed to be free of added materials like shielding fillers and sleeving leaves a cleaner signal. The high dielectric constant you have may actually have some benefit by being slowed making the treble less aggressive, thus less bright. jd |