Kimber Kable 8TC Exotic Speaker Cables that Look/Measure Great

gene

gene

Audioholics Master Chief
Administrator
Gene, I wonder if you might elaborate on this statement, "They measure considerably superior to standard 10AWG zip cord..."

What is "standard 10AWG zip cord"?

In looking at the DIY Cable Faceoff measurements, the Sound King V1 seems pretty "standard". Yet, it measured lower Rs ( 2.17 average vs 2.9 for the 8PR and 5.6 for the 4PR) lower C (20.81 pF/Ft vs 87 for the 8PR and 39 for the 4PR). In fact, though we don't have DCR in the Faceoff to compare to (odd?) the only metric where the Kimber actually measured "superior" was inductance: the V1 was higher at 0.213 uH/ft vs about .041 uH/ft for 8PR and .074 uH/ft for the 4PR. As for "considerably", yes in that parameter only, the Kimber does measure considerably better, but cable inductance at any of these levels is probably insignificant in therms of performance.

Perhaps I'm not looking at the same "standard 10AWG zip cord" you are, though. But it does seem there is a bit of a price differential...in the opposite direction with superior measurements except for inductance, even with some other cables in the Faceoff.

If you were referencing other "standard 10AWG", please post those measurements.

I also submit these hopefully constructive criticisms of the review structure: It would be helpful when providing test data to also provide a reference point where a given metric would become influential in a typical installation. How much Rs is a problem for a typical 25' run? How much C per foot would be an issue with a typical power amp and speaker? And so on, to scale the relative merits of each measurement for those unfamiliar with the effects. Otherwise, statements like the one quoted above may lead readers to assume that one particular cable is vastly superior to another in performance, when clearly that is not the case. It would also help graph readability to provide a better vertical scale that would make reading between the lines easier to estimate. Major divisions are easier to read if assigned to .1, .2 or .5 rather than .4.
The Kimber 8TC have 4 times less inductance than 10AWG Zip cord but also 4x capacitance as a result. The AC resistance is lower and flatter at high F, less skinning. Mostly academic for audio frequencies as the primary concern for speaker cables is resistance, followed by low inductance. The capacitance isn't extreme enough to cause amp oscillations on even the poorest designs for long runs. People spending this much on cables usually use small runs and top notch gear anyways.

"Superior" is a stretch to be certain but anyone who cares enough to read the measurements can put 2 + 2 together and determine if the much higher price is justified for better cosmetics and academically better measurable performance.

As for scaling, I suck with Excel but I will try to make the graphs clearer in future reviews.
 
Last edited by a moderator:
A

avengineer

Banned
The Kimber 8TC have 4 times less inductance than 10AWG Zip cord but also 4x capacitance as a result. The AC resistance is lower and flatter at high F, less skinning.
Sorry, I can't seem to find how you got the AC resistance comparison. We still haven't defined what "standard 10AWG Zip cord is, or where the reference measurements are posted, but if I look at the "Sound King V1", I'm not seeing that the 8TC has lower Rs, it's clearly higher, though the DIY faceoff data doesn't extend past 10KHz, and isn't in graphic form. However, the average of the Sound King is clearly lower, so you must not be referring to that. What cable are we comparing to?
Mostly academic for audio frequencies as the primary concern for speaker cables is resistance, followed by low inductance. The capacitance isn't extreme enough to cause amp oscillations on even the poorest designs for long runs. People spending this much on cables usually use small runs and top notch gear anyways.
What's bothersome here is not the ranking of parameters, but that there is no reference to degree. Is the implication that any inductance is bad? At what point can a buyer stop being concerned about capacitance?
"Superior" is a stretch to be certain but anyone who cares enough to read the measurements can put 2 + 2 together and determine if the much higher price is justified for better cosmetics and academically better measurable performance.
I'm not sure I agree. While it would be great if everyone who read the review understood the importance of each measurement, I don't think everyone who cares has enough tech background or could even make sense out of the measurements, especially in light of such a glowing review. But I see where you're going.
As for scaling, I suck with Excel but I will try to make the graphs clearer in future reviews.
Excel...it used to be so simple. I feel your pain. Thanks for the effort!
 
gene

gene

Audioholics Master Chief
Administrator
Sorry, I can't seem to find how you got the AC resistance comparison. We still haven't defined what "standard 10AWG Zip cord is, or where the reference measurements are posted, but if I look at the "Sound King V1", I'm not seeing that the 8TC has lower Rs, it's clearly higher, though the DIY faceoff data doesn't extend past 10KHz, and isn't in graphic form. However, the average of the Sound King is clearly lower, so you must not be referring to that. What cable are we comparing to?
What's bothersome here is not the ranking of parameters, but that there is no reference to degree. Is the implication that any inductance is bad? At what point can a buyer stop being concerned about capacitance?

I'm not sure I agree. While it would be great if everyone who read the review understood the importance of each measurement, I don't think everyone who cares has enough tech background or could even make sense out of the measurements, especially in light of such a glowing review. But I see where you're going.


Excel...it used to be so simple. I feel your pain. Thanks for the effort!
you can reference my BlueJeans 10AWG Cable review:
Blue Jeans 10AWG Speaker Cable 5T00UP Review | Audioholics

AC resistance (especially above 10kHz) is lower on the Kimber since they Kimber isn't skinning as badly. Also notice how much flatter and lower the Kimber inductance is.

Excel stopped being usable to me after the 2001 edition. Not I just limp through it. I hate Office 2010!
 
Irvrobinson

Irvrobinson

Audioholic Spartan
AC resistance (especially above 10kHz) is lower on the Kimber since they Kimber isn't skinning as badly. Also notice how much flatter and lower the Kimber inductance is.
Do you believe the difference is audible on your system, as compared to 10ga zip cord?
 
gene

gene

Audioholics Master Chief
Administrator
Do you believe the difference is audible on your system, as compared to 10ga zip cord?
It doesn't matter what I believe b/c I can't do a quick enough switch out to make a reliable determination. I believe they make the look of my system more impressive for sure though :)
 
A

avengineer

Banned
It doesn't matter what I believe b/c I can't do a quick enough switch out to make a reliable determination. I believe they make the look of my system more impressive for sure though :)
As an engineer doing electrical measurements, what would you expect the effect of those cable characteristics to be in a typical system?
 
A

avengineer

Banned
Here's a bit more analysis, for what it's worth. My question would be, what audible difference exists between the Kimber 8TC and the "standard 10 AWG" Bluejeans cable, and is that difference audible?

In an effort to answer that, or at least scale the results, I took advantage of an online circuit simulator, Circuit Lab
(https://www.circuitlab.com)

Taking the data from both reviews, I constructed a rough simulation of the cable including measured R, L and C. I did not include the skin effect because it is not simple to simulate using the available simulation components, and I recognize that skin effect may add additional differences to the results.

The basic cable equivalent I used is this:
Untitled-1.jpg
Values shown are for 20' of Kimber 8TC. The values for 20' of Bluejeans "standard" 10AWG were also simulated. I do recognize that the network is not an accurate representation of a long cable, which actually has all three properties distributed over the length. To simulate that accurately the network would have to be many sections of R, L and C to represent the cumulative effect. This would essentially create a multi-pole filter, so the extreme HF characteristics would be different than a single section network, however for the purposes of a 20' test piece, the difference in performance would be quite small.

I needed a load as close to a real speaker as possible. Rather than invent one, I borrowed a circuit from a Stereophile article from 1995, "Real-Life Measurements" by John Atkinson. Atkinson modified a circuit by Kantor by adding a Zobel network to more closely approximate the high frequency characteristics he'd measured on real speakers. The circuit performance seems reasonable, and can be seen on the link below. It may not simulate any specific speaker, but at least it's similar to speakers in general, and frankly, was handy.
stereophile-speaker-net.jpg
Input was applied at the junction of R9, R11 and R12, with reference to ground. The Stereophile article discussing this network is below.

Real-Life Measurements | Stereophile.com

AC frequency response simulations were run on the cable simulation network with values entered for each cable. Then I had my turn to fight with Excel's graphing (dis)abilities. What a mess. Anyway, the frequency response at the simulated speaker input for each cable is shown. The response was run from 20Hz to 20KHz, and the vertical axis is scaled in dB, with the maximum being a fraction of 1dB.
cable-speakerfr.jpg

Just for grins, here's the difference between the two 20' cables measured at the load:

bj-kimber.jpg

Now, as to what you are looking at, this is essentially a voltage frequency response measurement at the load input. It does not represent an acoustic response in a room, as the measurement is electrical only. The difference plot is what's most interesting, though. Note, for example, the cable with "worse" measurements shows more HF response, which, if we held to the idea that L and C were "bad" if they were higher, doesn't seem to make sense. However, speaker loads are reactive. What we have is a resonant circuit with the cable and the load. The actual resonant frequency is far above the audio band, but we are seeing the beginning of its effect. It is evident that lower distributed R, L and C contribute to flatter overall response, even though the specific amount of change is miniscule.

To offer some conclusions, measurements of electrical parameters of short lengths of speaker cable may seem to exaggerate their real impact, or even the exact direction of change if not considered as part of the entire circuit. The net change between the cables is well below audibility, even at the extreme. The maximum difference between the two occurs at a frequency where small changes are difficult to hear. To support that claim, I give you a graphic from David Clark's 1982 AES paper, "High Resolution Subjective Testing using a Double-Blind Comparator" in which he determined the ability to hear level matching at different frequencies. While not exactly indicative of the ability to hear level changes as they relate to frequency and Q (bandwidth) of the response deviation, it does illustrate the relative ability to discern level variance vs frequency.


response-matching.jpg

Each speaker will present a different load, so the FR curves and difference curves shown above will not represent the exact differences in specific cases. The load simulator is intended to be an average, more or less typical two-way bookshelf speaker. More complex speakers will have different results, but there's not reason to expect any of them to be extreme enough to become audible.

In short, I believe the differences between the Bluejeans cable and the Kimber 8TC to be completely inaudible.
 
Last edited:
Steve81

Steve81

Audioholics Five-0
In short, I believe the differences between the Bluejeans cable and the Kimber 8TC to be completely inaudible.
Is anybody here suggesting they would be audible? Gene was pretty clear in the review that
I am not one who attempts to discern the subtle sonic differences cables convey in an audio system. I am a firm believer that only poorly designed cables can be sonically distinguishable, and then only under the right conditions. That being said, my listening tests focused on pure enjoyment of the sound quality of my reference system. At no point did I feel the Kimber cables were adding a level of realism I’ve never heard before with my standard 10AWG Blue Jeans zip cord.
 
gene

gene

Audioholics Master Chief
Administrator
Here's a bit more analysis, for what it's worth. My question would be, what audible difference exists between the Kimber 8TC and the "standard 10 AWG" Bluejeans cable, and is that difference audible?

In an effort to answer that, or at least scale the results, I took advantage of an online circuit simulator, Circuit Lab
(https://www.circuitlab.com)

Taking the data from both reviews, I constructed a rough simulation of the cable including measured R, L and C. I did not include the skin effect because it is not simple to simulate using the available simulation components, and I recognize that skin effect may add additional differences to the results.

The basic cable equivalent I used is this:
View attachment 12105
Values shown are for 20' of Kimber 8TC. The values for 20' of Bluejeans "standard" 10AWG were also simulated. I do recognize that the network is not an accurate representation of a long cable, which actually has all three properties distributed over the length. To simulate that accurately the network would have to be many sections of R, L and C to represent the cumulative effect. This would essentially create a multi-pole filter, so the extreme HF characteristics would be different than a single section network, however for the purposes of a 20' test piece, the difference in performance would be quite small.

I needed a load as close to a real speaker as possible. Rather than invent one, I borrowed a circuit from a Stereophile article from 1995, "Real-Life Measurements" by John Atkinson. Atkinson modified a circuit by Kantor by adding a Zobel network to more closely approximate the high frequency characteristics he'd measured on real speakers. The circuit performance seems reasonable, and can be seen on the link below. It may not simulate any specific speaker, but at least it's similar to speakers in general, and frankly, was handy.
View attachment 12106
Input was applied at the junction of R9, R11 and R12, with reference to ground. The Stereophile article discussing this network is below.

Real-Life Measurements | Stereophile.com

AC frequency response simulations were run on the cable simulation network with values entered for each cable. Then I had my turn to fight with Excel's graphing (dis)abilities. What a mess. Anyway, the frequency response at the simulated speaker input for each cable is shown. The response was run from 20Hz to 20KHz, and the vertical axis is scaled in dB, with the maximum being a fraction of 1dB.
View attachment 12102

Just for grins, here's the difference between the two 20' cables measured at the load:

View attachment 12103

Now, as to what you are looking at, this is essentially a voltage frequency response measurement at the load input. It does not represent an acoustic response in a room, as the measurement is electrical only. The difference plot is what's most interesting, though. Note, for example, the cable with "worse" measurements shows more HF response, which, if we held to the idea that L and C were "bad" if they were higher, doesn't seem to make sense. However, speaker loads are reactive. What we have is a resonant circuit with the cable and the load. The actual resonant frequency is far above the audio band, but we are seeing the beginning of its effect. It is evident that lower distributed R, L and C contribute to flatter overall response, even though the specific amount of change is miniscule.

To offer some conclusions, measurements of electrical parameters of short lengths of speaker cable may seem to exaggerate their real impact, or even the exact direction of change if not considered as part of the entire circuit. The net change between the cables is well below audibility, even at the extreme. The maximum difference between the two occurs at a frequency where small changes are difficult to hear. To support that claim, I give you a graphic from David Clark's 1982 AES paper, "High Resolution Subjective Testing using a Double-Blind Comparator" in which he determined the ability to hear level matching at different frequencies. While not exactly indicative of the ability to hear level changes as they relate to frequency and Q (bandwidth) of the response deviation, it does illustrate the relative ability to discern level variance vs frequency.


View attachment 12104

Each speaker will present a different load, so the FR curves and difference curves shown above will not represent the exact differences in specific cases. The load simulator is intended to be an average, more or less typical two-way bookshelf speaker. More complex speakers will have different results, but there's not reason to expect any of them to be extreme enough to become audible.

In short, I believe the differences between the Bluejeans cable and the Kimber 8TC to be completely inaudible.
Nice analysis. I've been through all of this and more in past articles I've written when I went on a 2 year campaign debunking audio cable myths. I've come to the same conclusions in terms of miniscule differences as you've shown.

It doesn't matter how much math or analysis or logic you throw at this. Audiophiles enjoy high end, exotic looking cables and many of them reject the science or blind testing to prove or disprove there are audible differences between cables.

The Kimber cables do have better measurable results than standard 10AWG cable which I've shown. Audibility is questionable, but there is no reason to tell people they can't enjoy a cable like this more than a generic one. I never claim audibility differences in any of my cable reviews but others claim they can hear differences. More power to them.
 
Irvrobinson

Irvrobinson

Audioholic Spartan
In short, I believe the differences between the Bluejeans cable and the Kimber 8TC to be completely inaudible.
An excellent response, and I certainly agree with your conclusion. In an actual room, where the differences are only manifested through speakers, audibility is difficult to imagine.
 
slipperybidness

slipperybidness

Audioholic Warlord
I Much Prefer JMP to Excel

I kind of get a chuckle out of the Excel-bashing. Yup, they should have left well enough alone and stopped at about version 2007 or even 2003.

I'm sure it is overkill for most of the stuff this industry would need it for, but I have moved along to JMP software from SAS. It's probably expensive too, but my employer has licenses for it.

It is way better than excel for many purposes, graphing, designing experiments, visualizing large data sets, statistics, and analyzing co-variances etc. It is incredibly user friendly and analyzing data is all drag-and-drop. I can even drag data and hover to get an instant preview, if it isn't showing me what I want to see, then I just drag to a different hot-spot.

On top of that, the customer support is top notch and they pride themselves on this fact. If you got a problem that you can't figure out how to use JMP for it, then you can give them a call and get support from a true expert. Try getting that out of the Gates' Compound.
 
Speedskater

Speedskater

Audioholic General
For those interested in doing serious circuit analiys of speaker cables and amplifier/cable/speaker systems, do a search for these old Cyril Bateman Articles. (they don't seem to have a permanent URL). These papers are technical and not easy reading.

<!--[if gte mso 9]><![endif]--> Cyril Bateman Articles

Electronics World Magazine

Measuring Speaker Cables: 1 Cyril Bateman Dec 1996 p925
Measuring Speaker Cables: 2 Cyril Bateman Jan 1997 p52
Measuring Speaker Cables: 3 Cyril Bateman Feb 1997 p119
<!--[if gte mso 9]><![endif]--><!--[if gte mso 10]> <![endif]-->
 
Last edited by a moderator:
A

avengineer

Banned
Nice analysis. I've been through all of this and more in past articles I've written when I went on a 2 year campaign debunking audio cable myths. I've come to the same conclusions in terms of miniscule differences as you've shown.

It doesn't matter how much math or analysis or logic you throw at this. Audiophiles enjoy high end, exotic looking cables and many of them reject the science or blind testing to prove or disprove there are audible differences between cables.

The Kimber cables do have better measurable results than standard 10AWG cable which I've shown. Audibility is questionable, but there is no reason to tell people they can't enjoy a cable like this more than a generic one. I never claim audibility differences in any of my cable reviews but others claim they can hear differences. More power to them.
I simply attempted to place the measurements in a more realistic perspective. The review devoted a lot of space to the measurement results, then stated emphatically that the Kimber measured better with any reference to the degree of importance. It was about like having two credit card accounts, one with a $4999 available balance, and one with a $5000 available balance, then noting you could clearly buy a lot more with the $5000 account.
 
Adam

Adam

Audioholic Jedi
It was about like having two credit card accounts, one with a $4999 available balance, and one with a $5000 available balance, then noting you could clearly buy a lot more with the $5000 account.
Actually, it would be more like he noted that you clearly had more credit with the $5000 account. :) I don't think that he said how much more it would buy you.

I do like the analogy, though.
 
jinjuku

jinjuku

Moderator
The comments are already flowing on that one. No SBT or DBT? Then no valid results.
 

Latest posts

newsletter

  • RBHsound.com
  • BlueJeansCable.com
  • SVS Sound Subwoofers
  • Experience the Martin Logan Montis
Top