Different cables, different measurements?

[antcollinet]

The quote is correct and applies very well to many contexts (although certainly Henry probably could care less about cables).

The quote is more an inspirational view regarding self belief and how it relates to achievement. Rather than believing you have golden ears that can hear as well as bats. In which case thinking you can doesn't result in reality.

 

[Stoutblock]

The quote is more an inspirational view regarding self belief and how it relates to achievement. Rather than believing you have golden ears that can hear as well as bats. In which case thinking you can doesn't result in reality.

You are absolutely right in the context Henry used it for. That was the world he lived in. In his world, the context was to refer to the ability to accomplish something or not. What you 'think' the ability is, or inability is, is not relevant.

Of course it's true that you 'think' something. The fact the 'thought' is true or false is separate from the fact you 'think' it. In a broader sense, the quote can easily be applied to most any subject to illustrate just because you 'think' something to be true or false does not make it so. It exposes the risk of simply 'thinking' your 'thoughts' to be true.

In this context my point is; "Whether you 'think' you can hear a difference in cables, or whether you 'think' you cannot hear a difference--you are right."

"The truth (data) will set you free." Something like this in the Bible...

 

[Jukka]

FWIW I once tested full frequency response of one speaker cable by changing the geometry, how the cable was tied, by measuring speaker output with a measurement mic. It produced the exact same result each time, variance less than 0.3 dB. The key is that the speaker and the mic should not move, be very close to each other and everything else in the room, including you and the door, should be the same for each measurement. And you need filters, like windowing, it will help to get consistent results. So yes you can get repeatable results with a speaker and a mic when testing a cable, but your measurement suite is limited to what you can get with a mic and the results are most likely not comparable beyond the session.

 

[antcollinet]

variance less than 0.3 dB

And that variance will be simply run to run variation with nothing changing. You can't get much better than that when measuring acoustically.

 

[HaveMeterWillTravel]

Usage of science terms that sound awesome on Google but have minimal actual practical use in even the context that is being quoted: Check

Find your graphics cable or TV cable or thunderbolt3 or whatever stuff that is capable of 5GHz frequency and cut them and and observe that none of them use Litz wire, for a very simple reason that is mentioned on wikipedia:


Source: People whose knowledge come from actually using stuff at RF frequencies instead of 5 minutes of Googled forum reading

To anyone else reading who is programming your word filter to detect audiophoolery, add this term to the list.

I think one should try using 1.85mm semi-rigid cable assemblies for more high frequency ambiance.

 

[HaveMeterWillTravel]

FWIW I once tested full frequency response of one speaker cable by changing the geometry, how the cable was tied, by measuring speaker output with a measurement mic. It produced the exact same result each time, variance less than 0.3 dB. The key is that the speaker and the mic should not move, be very close to each other and everything else in the room, including you and the door, should be the same for each measurement. And you need filters, like windowing, it will help to get consistent results. So yes you can get repeatable results with a speaker and a mic when testing a cable, but your measurement suite is limited to what you can get with a mic and the results are most likely not comparable beyond the session.

In other disciplines, one would simply measure it directly using a HP/Keysight impedance analyzer or similar. But audio? noooo....

 

[Jukka]

In other disciplines, one would simply measure it directly using a HP/Keysight impedance analyzer or similar. But audio? noooo....

I can measure impedance, but I wasn't sure if that would fully reflect the cable together with the speaker. After all, the cable would have had an effect onto the impedance or capacitance and changing either would have had the combined effect with the speakers own crossover. The point was to make the scenario reflect real world listening conditions.

PS. Changes in the physical measurement environment have effects in impedance measurement results, so in that too you should keep everything the same between measurements. The effect can be small, like if you have some object in front of the speaker that is moved, or large if you plug the reflex port or move the speakers face into a wall.

 

[Speedskater]

I think one should try using 1.85mm semi-rigid cable assemblies for more high frequency ambiance.

Doubtful, very doubtful.
Total cable inductance with respect to the speaker's high frequency impedance might have a very small impact.

 

[HaveMeterWillTravel]

I can measure impedance, but I wasn't sure if that would fully reflect the cable together with the speaker. After all, the cable would have had an effect onto the impedance or capacitance and changing either would have had the combined effect with the speakers own crossover. The point was to make the scenario reflect real world listening conditions.

I would not expect the impedance of the cable itself to change appreciably enough to matter, unless it's simply too small and it encounters Ohmic heating.
If you wish to measure the electrical transfer function as a whole, you would need to measure at the individual speaker terminals.

It also depends on how "good" of a measurement one wishes. At every dissimilar metal joint/connection, there will be a very small offset voltage created by the thermoelectric effect. However, it would be so minor I am incredulous that it'll have any audible effect. Hmm. Possibly for tonearms/cartridges but don't know much about them.

PS. Changes in the physical measurement environment have effects in impedance measurement results, so in that too you should keep everything the same between measurements. The effect can be small, like if you have some object in front of the speaker that is moved, or large if you plug the reflex port or move the speakers face into a wall.

I would assume at audio frequencies, any meaningful variation due to movement would be either lose or cracked conductivity in the circuit with a sub-population of specific situations where a cable is being moved closer or father away from an EMI noise source.

At extremely low amplitudes, RF frequencies, and other non-relevent areas, the triboelectric effect can be the dominate measurement uncertainty factor. That is why typically such measurements are done with fixtures.


Here is a simple device to measure how large the effect is for a particular cable:
Credit to: https://www.minicircuits.com/appdoc/AN46-003.html

 

[Jukka]

I would not expect the impedance of the cable itself to change appreciably enough to matter, unless it's simply too small and it encounters Ohmic heating.
If you wish to measure the electrical transfer function as a whole, you would need to measure at the individual speaker terminals.

It also depends on how "good" of a measurement one wishes. At every dissimilar metal joint/connection, there will be a very small offset voltage created by the thermoelectric effect. However, it would be so minor I am incredulous that it'll have any audible effect. Hmm. Possibly for tonearms/cartridges but don't know much about them.


I would assume at audio frequencies, any meaningful variation due to movement would be either lose or cracked conductivity in the circuit with a sub-population of specific situations where a cable is being moved closer or father away from an EMI noise source.

At extremely low amplitudes, RF frequencies, and other non-relevent areas, the triboelectric effect can be the dominate measurement uncertainty factor. That is why typically such measurements are done with fixtures.


Here is a simple device to measure how large the effect is for a particular cable:
Credit to: https://www.minicircuits.com/appdoc/AN46-003.html

In my experiment I had a 5 meter long speaker cable that I rolled up like a coil. The other arrangement was to set it parallel like a capacitor. The result was no measurable difference at any frequency. So it doesn't seem to audibly matter how you manage your cabling if you want everything neat and tidy.

If memory serves, I repeated the test twice because I expected more run to run variance, but there just wasn't any.

 

[Doodski]

In my experiment I had a 5 meter long speaker cable that I rolled up like a coil. The other arrangement was to set it parallel like a capacitor. The result was no measurable difference at any frequency. So it doesn't seem to audibly matter how you manage your cabling if you want everything neat and tidy.

If memory serves, I repeated the test twice because I expected more run to run variance, but there just wasn't any.

I experienced a cable coil issue with a customer that had a 12 foot actuated TV satellite dish installed and setup. The customer complaint was, "Fuzzy picture." So I went over to check it out and he had made a very nice tight coil package of all the wires behind the AV rack. A substantial part of that was the heavy duty gauge RG coax cable and DC voltage cable for the positive and negative channels pola rotor and LNB amplifier mounted at the middle of the dish where the focused tiny amount of energy from the satellites is concentrated. With all the AC wires, RCA cables and the multiple windings of the extremely low signal strength RG cable the picture was suffering. It was fuzzy and sparkly and so I disassembled the coil and the picture went to perfect. So a coil of wire can affect some cabling but the extremely low signal strength from the wire that came from the dish LNB and pola rotor is very very susceptible to outside influence. I don't remember the signal strength of that wire but it is tiny tiny. So watch your wires and be careful.... LoL.

 

[Speedskater]

I think that it was more a mechanical problem that the RG8 coax acting as an electrical coil.
Or part of the RF signal was traveling on the DC cable rather than the coax shield.
* * * * * * * * * *
Tight coiling could have caused crimps in the coax cross-section from place to place on the cable, resulting in signal reflections.
Belden writes about how at near gigahertz frequencies the coax cross-section needs to be very round for every inch of the cable.