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Review Speaker Cables

itor

Member
Sep 7, 2020
1
1
20
Technical note, about speaker cables ...

I was wondering ...
What is the order of magnitude ...
Which is the significance ?, of the resistanse (Ohm /m) of the speaker cables ...

{ For the interconnection, between amp stages, it was analyzed in another technical note ...
That there is, indeed (depending on the case) the need for low-capacitance cabling (< ... pF / m) }

But the speakers have low resistance (as loads) ...
Usually 4 or 8 Ohm ...
In fact:
Impedance, Ζ (jw) ...
Which can vary (in metre) as a function of frequency, ...
From (lets say) ...
2 Ω ... 8 Ω
{ depending on the implementation }

I thought, qualitatively and quantitatively the issue ...

Let assume a connection cable of 2 m ...
It can have (ohmic) resistance ...
Of the order of ... 0.2 Ohm
{ a cheap one }

The loss (in dB) would be negligible ...
One thinks at first glance ...

Here is a simple, careful reasoning:

(1) IF someone uses a 0.2 Ohm cable ...
For a fluctuating (with the frequency) load:
2 ... 8 Ω
Then he gets a VARYING loss (depending on frequency !)
Loss οf the order of:
-0.8 ... -0.2 dB

Actually!
A sensitive "musical ear" can feel and detect this variation (change) in the original signal ...
NO from the "negligible" loss (-0.5 dB) ...
But from the fact that it is NOT stable ! ...

===

IF someone used an "exotic" but unfortunately much more expensive cable ...
E.g. with ohmic resistance of
0.02 Ω ...

With the same fluctuating (with frequency) load:
2 ... 8 Ω

Then he gets a VARYING loss (depending on frequency !)
Loss οf the order of:
-0.08 ... -0.02 dB

So minor fluctuation of loss (in dB) ...
Is (likely) not perceived by the human ear ...

===

Regarding the dynamic response of the system (cable - speaker) ...

The capacitance (pF / m) ...
And the corresponding induction (nH / m) ...

They are so small ...
And the load resistance is also small (few Ohm) ...

... so that finally the poles of the system, that are inserted by the "capacitor" and the "coil" of the cable ...
They can be over 200 kHz ...
That does not change the phase ...
Not even at 20 kHz (at the limits of the human hearing) ...

Therefore, these cable parameters, do not seem to be decisive ...
{ for the speaker cables ... }

While they are critical for the interconnection of amp stages, where the input resistance is of the order of kOhm ...
{ as discussed in another article }

View: https://www.facebook.com/ioannis.tortopidis/posts/10216516371927745


{ i will try to translate, when i find some time in peace }

===
 
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plus 1

Well-known member
Dec 5, 2019
865
146
570
Technical note, about speaker cables ...

I was wondering ...
What is the order of magnitude ...
Which is the significance ?, of the resistanse (Ohm /m) of the speaker cables ...

{ For the interconnection, between amp stages, it was analyzed in another technical note ...
That there is, indeed (depending on the case) the need for low-capacitance cabling (< ... pF / m) }

But the speakers have low resistance (as loads) ...
Usually 4 or 8 Ohm ...
In fact:
Impedance, Ζ (jw) ...
Which can vary (in metre) as a function of frequency, ...
From (lets say) ...
2 Ω ... 8 Ω
{ depending on the implementation }

I thought, qualitatively and quantitatively the issue ...

Let assume a connection cable of 2 m ...
It can have (ohmic) resistance ...
Of the order of ... 0.2 Ohm
{ a cheap one }

The loss (in dB) would be negligible ...
One thinks at first glance ...

Here is a simple, careful reasoning:

(1) IF someone uses a 0.2 Ohm cable ...
For a fluctuating (with the frequency) load:
2 ... 8 Ω
Then he gets a VARYING loss (depending on frequency !)
Loss οf the order of:
-0.8 ... -0.2 dB

Actually!
A sensitive "musical ear" can feel and detect this variation (change) in the original signal ...
NO from the "negligible" loss (-0.5 dB) ...
But from the fact that it is NOT stable ! ...

===

IF someone used an "exotic" but unfortunately much more expensive cable ...
E.g. with ohmic resistance of
0.02 Ω ...

With the same fluctuating (with frequency) load:
2 ... 8 Ω

Then he gets a VARYING loss (depending on frequency !)
Loss οf the order of:
-0.08 ... -0.02 dB

So minor fluctuation of loss (in dB) ...
Is (likely) not perceived by the human ear ...

===

Regarding the dynamic response of the system (cable - speaker) ...

The capacitance (pF / m) ...
And the corresponding induction (nH / m) ...

They are so small ...
And the load resistance is also small (few Ohm) ...

... so that finally the poles of the system, that are inserted by the "capacitor" and the "coil" of the cable ...
They can be over 200 kHz ...
That does not change the phase ...
Not even at 20 kHz (at the limits of the human hearing) ...

Therefore, these cable parameters, do not seem to be decisive ...
{ for the speaker cables ... }

While they are critical for the interconnection of amp stages, where the input resistance is of the order of kOhm ...
{ as discussed in another article }

View: https://www.facebook.com/ioannis.tortopidis/posts/10216516371927745


{ i will try to translate, when i find some time in peace }

===
so are you saying different designs of cables make a difference that we can or can not actually hear or what ?!
 
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hilroy48

Active member
Sep 13, 2020
12
7
25
I will share my thoughts. I have learned the shorter the cable the better, 8-10 feet. I have a decent, yet older cable, Nordost Purple Flare, mine is actually 15' long. I have decided to upgrade all of my interconnect cables and power cables first. I am told those will give you the most noticeable hearing difference. And they honestly did. Once my new speakers arrive, i will listen to the system for a couple of 3 weeks, then borrow a set of wire world speaker cables from my dealer and swap them out see how much of a difference i notice .
 
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plus 1

Well-known member
Dec 5, 2019
865
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I will share my thoughts. I have learned the shorter the cable the better, 8-10 feet. I have a decent, yet older cable, Nordost Purple Flare, mine is actually 15' long. I have decided to upgrade all of my interconnect cables and power cables first. I am told those will give you the most noticeable hearing difference. And they honestly did. Once my new speakers arrive, i will listen to the system for a couple of 3 weeks, then borrow a set of wire world speaker cables from my dealer and swap them out see how much of a difference i notice .
please can you report back your findings.
 

abacus

Well-known member
Sep 24, 2008
402
160
19,070
Don’t forget to use the double blind test and make sure the level is balanced between the 2, so that you can remove as many variables as possible. (Any other type of test cannot be verified)

Bill
 
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plus 1

Well-known member
Dec 5, 2019
865
146
570
Don’t forget to use the double blind test and make sure the level is balanced between the 2, so that you can remove as many variables as possible. (Any other type of test cannot be verified)

Bill
all true yes but do people do the same procedure when testing a new source, amplifier or speakers ?!
 
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shadders

Well-known member
Nov 19, 2009
152
88
18,670
Technical note, about speaker cables ...

I was wondering ...
What is the order of magnitude ...
Which is the significance ?, of the resistanse (Ohm /m) of the speaker cables ...

{ For the interconnection, between amp stages, it was analyzed in another technical note ...
That there is, indeed (depending on the case) the need for low-capacitance cabling (< ... pF / m) }

But the speakers have low resistance (as loads) ...
Usually 4 or 8 Ohm ...
In fact:
Impedance, Ζ (jw) ...
Which can vary (in metre) as a function of frequency, ...
From (lets say) ...
2 Ω ... 8 Ω
{ depending on the implementation }

I thought, qualitatively and quantitatively the issue ...

Let assume a connection cable of 2 m ...
It can have (ohmic) resistance ...
Of the order of ... 0.2 Ohm
{ a cheap one }

The loss (in dB) would be negligible ...
One thinks at first glance ...

Here is a simple, careful reasoning:

(1) IF someone uses a 0.2 Ohm cable ...
For a fluctuating (with the frequency) load:
2 ... 8 Ω
Then he gets a VARYING loss (depending on frequency !)
Loss οf the order of:
-0.8 ... -0.2 dB

Actually!
A sensitive "musical ear" can feel and detect this variation (change) in the original signal ...
NO from the "negligible" loss (-0.5 dB) ...
But from the fact that it is NOT stable ! ...

===

IF someone used an "exotic" but unfortunately much more expensive cable ...
E.g. with ohmic resistance of
0.02 Ω ...

With the same fluctuating (with frequency) load:
2 ... 8 Ω

Then he gets a VARYING loss (depending on frequency !)
Loss οf the order of:
-0.08 ... -0.02 dB

So minor fluctuation of loss (in dB) ...
Is (likely) not perceived by the human ear ...

===

Regarding the dynamic response of the system (cable - speaker) ...

The capacitance (pF / m) ...
And the corresponding induction (nH / m) ...

They are so small ...
And the load resistance is also small (few Ohm) ...

... so that finally the poles of the system, that are inserted by the "capacitor" and the "coil" of the cable ...
They can be over 200 kHz ...
That does not change the phase ...
Not even at 20 kHz (at the limits of the human hearing) ...

Therefore, these cable parameters, do not seem to be decisive ...
{ for the speaker cables ... }

While they are critical for the interconnection of amp stages, where the input resistance is of the order of kOhm ...
{ as discussed in another article }

View: https://www.facebook.com/ioannis.tortopidis/posts/10216516371927745


{ i will try to translate, when i find some time in peace }

===
Hi,
If you examine one of the cheapest speaker cables, QED79, it has a loop resistance of 0.016ohms, such that 1 metre length, the cable conductor has a resistance of 0.008ohms. This is negligible considering that the impedance of the speaker may be 4ohms, which is 500x greater.

Here is the QED79 strand modelled with an 8ohm resistance load, from 10Hz to 20kHz. Notice that the drop in frequency response from 10Hz to 20kHz is 0.00175dB.

2020_09_25_79Strand.jpg

Essentially, there is no difference in frequency response. The cable parameters are such that it will not affect the amplifier.

Regards,
Shadders.
 
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plus 1

Well-known member
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Hi,
If you examine one of the cheapest speaker cables, QED79, it has a loop resistance of 0.016ohms, such that 1 metre length, the cable conductor has a resistance of 0.008ohms. This is negligible considering that the impedance of the speaker may be 4ohms, which is 500x greater.

Here is the QED79 strand modelled with an 8ohm resistance load, from 10Hz to 20kHz. Notice that the drop in frequency response from 10Hz to 20kHz is 0.00175dB.

View attachment 1587

Essentially, there is no difference in frequency response. The cable parameters are such that it will not affect the amplifier.

Regards,
Shadders.
so (without me seeming like an idiot) can you explain to me what that means ?!
are you saying qed 79 strand is the pinnacle of loudspeaker cables ?
 
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shadders

Well-known member
Nov 19, 2009
152
88
18,670
so (without me seeming like an idiot) can you explain to me what that means ?!

are you saying qed 79 strand is the pinnacle of loudspeaker cables ?
Hi,
Yes - it has very low inductance per metre, and reasonably low capacitance per metre (and very low compared to exotic cables), and for £2.25 per metre, you really cannot get better than that.

What the above means is that at 20kHz, the signal is attenuated by 0.00175dB compared to 0.0dB at 10kHz for example. The roll off is very gentle, and no one could determine the difference, or the slight attenuation at 20kHz.

Regards,
Shadders.
 
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plus 1

Well-known member
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Hi,
Yes - it has very low inductance per metre, and reasonably low capacitance per metre (and very low compared to exotic cables), and for £2.25 per metre, you really cannot get better than that.

What the above means is that at 20kHz, the signal is attenuated by 0.00175dB compared to 0.0dB at 10kHz for example. The roll off is very gentle, and no one could determine the difference, or the slight attenuation at 20kHz.

Regards,
Shadders.
thanks for the detailed reply - appreciated.
may i ask is switching to a thicker (say 500 strand) cable, with its lower resistance, not a factor / of importance ?
 

shadders

Well-known member
Nov 19, 2009
152
88
18,670
thanks for the detailed reply - appreciated.
may i ask is switching to a thicker (say 500 strand) cable, with its lower resistance, not a factor / of importance ?
Hi,
In the big scheme of things, then no, there will be no difference as long as the resistance, capacitance, and inductance per metre is similar to QED 79 strand. Although, it may be such a large diameter it will not fit into the banana plugs, or speaker terminals depending on how you approach it.

Regards,
Shadders.
 
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plus 1

Well-known member
Dec 5, 2019
865
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Hi,
In the big scheme of things, then no, there will be no difference as long as the resistance, capacitance, and inductance per metre is similar to QED 79 strand. Although, it may be such a large diameter it will not fit into the banana plugs, or speaker terminals depending on how you approach it.

Regards,
Shadders.
once again thanks for your thoughts.
do you believe that radio frequency interference and electromagnetic interference are problems that effect speaker cable performance ?
 

shadders

Well-known member
Nov 19, 2009
152
88
18,670
once again thanks for your thoughts.
do you believe that radio frequency interference and electromagnetic interference are problems that effect speaker cable performance ?
Hi,
EMI is RF interference - RF suggests a specific frequency band.

No, the cable is unaffected by EMI. The cable will conduct regardless of the external signals, exactly the same as per its specification.

EMI can be a problem for equipment, and i have heard the old CB radios used for taxi cabs in my speakers, many years ago, or the burst of the GSM phone. It could be the speaker coils responding to the EMI amplitude modulation.

There is the suggestion that the EMI will ingress into the amplifier feedback path. It is possible for a poorly designed amplifier. For most amplifiers, there will be an output coil, and a zobel network (possibly 2). Both attenuate any induced EMI into the speaker cable reaching the feedback circuit of an amplifier. Even for wifi, GSM etc., the amount of energy that does reach the feedback path has a power density lower than the thermal noise of the feedback resistances.

Of course, there are extreme cases, if you live near a radio transmitter - Brookmans Park North London does have houses quite close - this could be an issue, but speaker cables are generally in a position that does not allow for the ease of EMI induction.

Regards,
Shadders.
 
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plus 1

Well-known member
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Hi,
EMI is RF interference - RF suggests a specific frequency band.

No, the cable is unaffected by EMI. The cable will conduct regardless of the external signals, exactly the same as per its specification.

EMI can be a problem for equipment, and i have heard the old CB radios used for taxi cabs in my speakers, many years ago, or the burst of the GSM phone. It could be the speaker coils responding to the EMI amplitude modulation.

There is the suggestion that the EMI will ingress into the amplifier feedback path. It is possible for a poorly designed amplifier. For most amplifiers, there will be an output coil, and a zobel network (possibly 2). Both attenuate any induced EMI into the speaker cable reaching the feedback circuit of an amplifier. Even for wifi, GSM etc., the amount of energy that does reach the feedback path has a power density lower than the thermal noise of the feedback resistances.

Of course, there are extreme cases, if you live near a radio transmitter - Brookmans Park North London does have houses quite close - this could be an issue, but speaker cables are generally in a position that does not allow for the ease of EMI induction.

Regards,
Shadders.
thats a detailed reply - once again fully appreciated. i have one final question. may i ask have you tested an audioquest solid core, kimber woven and / or a nordost ribbon speaker cable on the machine / analyzer as displayed in post #17 and, if yes, what did it show when compared to the qed 79 strand ?
 

shadders

Well-known member
Nov 19, 2009
152
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18,670
thats a detailed reply - once again fully appreciated. i have one final question. may i ask have you tested an audioquest solid core, kimber woven and / or a nordost ribbon speaker cable on the machine / analyzer as displayed in post #17 and, if yes, what did it show when compared to the qed 79 strand ?
Hi,
I have not tested the cables you have mentioned. Do you have the electrical specifications for the cables ?.

My PC sound for Firefox is not working, so i may examine the video using Chrome later.

For a cable, you want the lowest resistance, capacitance, and inductance per metre you can find.

The Nordost ribbon cable - i looked at the 4 flat speaker cable, and the capacitance is 21pF per metre, and the inductance is 510nH per metre (i used 3 feet per metre), so the inductance and the capacitance is lower.

2020_09_25_79Strand_Nordost4Cable.jpg

I have assumed that the Nordost resistance per metre is the same as the QED79, and above shows the frequency response. The QED79 is 0.0008dB lower at 20kHz from the Nordost. You will not be able to hear this difference.

The other aspect, the vendor videos do need to be taken with a pinch of salt. I have seen videos where the other cable is coiled up, yet the "better cable" is uncoiled. I have seen a video where the testing equipment is very old, and the oscilloscope trace is blurry. Another video, the vendor stated that they had discovered a new type of distortion, but alas, the demonstration could not proceed due to a power outage, despite the lights being on etc.

There are amplifiers poorly engineered - one make has a devout following, and their amplifiers do not include the output inductor - so any cable with a high capacitance causes instability in the amplifier, unless that cable has significant inductance per metre.

Regards,
Shadders.
 
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