[NoahH]

In the recent Focal video, Danny makes the normal point about having ferrous metals in / near the signal path.

I know the virtues of copper itself, but I realized that I don't actually know the exact issue with having ferrous metals in or near the signal path. I can make some guesses, but I realized I should just ask why this is bad exactly. To be clear, I don't doubt it is bad, I just don't know the reason and want to learn.

[FullRangeMan]

Ferrous metals are magnetic and interfere with the electrical signals traveling in the circuits.

[Hobbsmeerkat]

Ferrous material tends to impart a grittiness to the sound, and the more of it there it the more noticeable it is, especially when directly in the signal path.

[ebag4]

The obvious and practical answer, at least with regard to common metals, is that non-ferrous metals are better conductors of electricity.  Copper , silver, gold are commonly used in electronics when quality of the signal matters, why would you use something inferior to your cable quality at the component end?

My $.02

Best,
Ed

[NoahH]

Ferrous metals are magnetic and interfere with the electrical signals traveling in the circuits.

This is my point though - I assume it interferes some how (that is a very generic term) but what is the mechanism?

E.g. wires passing through a *moving* magnetic field get induced current, but this is not moving.

[NoahH]

Ferrous material tends to impart a grittiness to the sound, and the more of it there it the more noticeable it is, especially when directly in the signal path.

Knowing the effect is helpful on this. Do you happen to know the suspected mechanism?

Ebag4 - your suggestion makes sense too. I.e. nothing is wrong with being ferrous, it just happens to be a correlation with bad conductors, so is an easy test.

I realize writing this that there may also be a conflation: ferrous metals in the signal path may be bad for a different reason that one's near the signal path are bad. Ex. The 'correlation' point would work for in the signal path but not near the signal path.

[corndog71]

My understanding of it goes like this.   A music signal on a speaker cable is an alternating electrical current.  The current flows along the surface of the metal wire.  The dielectric can affect that current by means of capacitance in that it can hold some of that current or slow down the signal at some but not necessarily all frequencies.  This can be observed in most zip cord by the dulling of higher frequencies by the cheap pvc dielectric used.  Teflon dielectrics are better because they don’t hold the charge as long as pvc does.  This is also affected by the distance between the 2 or more conductors as well as their angle to each other.

Inductance is also a factor due to the use of 2 or more wires in close proximity.  The goal of having less of this being a factor is always balanced by the capacitance.  Raising one lowers the other.  I don’t know off hand what the observed effect of too much inductance is but it’s likely also a smearing or delaying of the signal at various frequencies.

Finally there’s resistance.  This is the easiest factor to understand and observe.  More wire surface provides less resistance to the flow of current.  Just compare an 18awg wire to a 12awg wire and don’t adjust for level.  The smaller wire is more resistant and therefore less efficient at allowing the current to flow.  Bigger is better but don’t forget the other properties.

Now add a ferrous metal in the path which, if it’s magnetic, will hold an electrical charge.  That will affect any music signal riding that pathway even if it’s only slight.  Sadly it’s likely not a measurable difference unless you have very precise lab grade measurement tools. 

So if you want less distortion of the music signal it’s best to minimize the things that will negatively affect the signal.

[Mike B.]

The technical term is Hysteresis

[NoahH]

Corndog - agreed on those attributes of wires (and other conductors) generally. 100%

You make a remark at the end about ferrous metals, if magnetic, holding some energy. Do you mean there is some capacitance that is higher? The only other energy I know of in a magnetic material is that there was usually some energy consumed in aligning the molecules consistently to give it permanent magnetism.

Mike - hysteresis is a great lead on this. I know the term but had not tried to apply it here. What exact phenomena do you think has the lagging effect here?

I appreciate the engagement here everyone - I am chasing this because, like Corndogs general comment, I find understanding the mechanisms is helpful wherever possible, and the exact one here is interesting.

[FullRangeMan]

This is my point though - I assume it interferes some how (that is a very generic term) but what is the mechanism?

E.g. wires passing through a *moving* magnetic field get induced current, but this is not moving.

I know of no AC electricity that is not in motion.

The mechanism is electromagnetism, every electric field has an associated magnetic field being interfered by ferrous metals.

[NoahH]

I know of no AC electricity that is not in motion.

The mechanism is electromagnetism, every electric field has an associated magnetic field being interfered by ferrous metals.

Motion in that context is the physical wire movement - not the current.

The magnetic field generated by the current is there regardless of the conductor.

[FullRangeMan]

Motion in that context is the physical wire movement - not the current.

The magnetic field generated by the current is there regardless of the conductor.

Wires do not physically move on their own.
The magnetic field generated by the current is there regardless of the conductor.
This statement is correct, not relevant to the topic ferrous metals original question, it disregards the fact that ferrous metals alter the electro-magnetic field when when physically close.The conductor usually is copper which is non-magnetic.

[Cheytak.408]

Motion in that context is the physical wire movement - not the current.

The magnetic field generated by the current is there regardless of the conductor.

The terms are bound charges and electrostriction.  These can induce movement in the wiring as well as cause phase distortion and hysteresis effects in the conductors.  These are arcane as hell, but are real players in ultimate SQ. 

Yeah: I know........ 😏

[NoahH]

Wires do not physically move on their own.
The magnetic field generated by the current is there regardless of the conductor.
This statement is correct, not relevant to the topic ferrous metals original question, it disregards the fact that ferrous metals alter the electro-magnetic field when when physically close.The conductor usually is copper which is non-magnetic.

This is reductive and rude. I was trying to be polite in earlier notes on this.

Interference either means 2 waves interacting, which is not the case here, or is an incredibly general term. You can describe literally everything in audio with the word 'interference' if you use the lay version of it, and a lot of the behavior in with the 2 wave version. We use actual specific terms for the different kinds because they are different. Thus if someone on this forum were to ask why you don't want sharp cabinet edges, we would all tell them about baffle diffraction, not 'interference' even though the latter is technically true.

'Electromagnetism' is even more vague and less accurate. Electromagnetism is NOT a mechanism of anything. It is a branch of physics. That is akin to saying that a lens works because of 'optics'. It is, at best, a tautology.

Now the thing about magnetic fields being interfered with by ferrous materials - this is still not helping anything. 'interfere' is again being used in a non-specific way. Magnetic fields are shaped by *a lot of things*. Ferrous materials are not the only things that affect the field shape. And this only relates to ferrous objects that are not part of the conductor itself - the material of the inductor does not, AFAIK, affect the shape of the generated field.

Combinations of general terms 'interference' and 'magnetic' is not adding anything.

To give a better example of what I am fishing for: does the fluctuating magnetic field from the audio signal pulling on ferrous materials outside the conductor create non-linear resistance with magnitude of current? Do ferrous materials have slower changes in their induced magnetic fields because the domains keep their current alignment for a moment after current drops, and that has a some effect on the wires inductance or resistance?

[FullRangeMan]

This is reductive and rude. I was trying to be polite in earlier notes on this.

Interference either means 2 waves interacting, which is not the case here, or is an incredibly general term. You can describe literally everything in audio with the word 'interference' if you use the lay version of it, and a lot of the behavior in with the 2 wave version. We use actual specific terms for the different kinds because they are different. Thus if someone on this forum were to ask why you don't want sharp cabinet edges, we would all tell them about baffle diffraction, not 'interference' even though the latter is technically true.

'Electromagnetism' is even more vague and less accurate. Electromagnetism is NOT a mechanism of anything. It is a branch of physics. That is akin to saying that a lens works because of 'optics'. It is, at best, a tautology.

Now the thing about magnetic fields being interfered with by ferrous materials - this is still not helping anything. 'interfere' is again being used in a non-specific way. Magnetic fields are shaped by *a lot of things*. Ferrous materials are not the only things that affect the field shape. And this only relates to ferrous objects that are not part of the conductor itself - the material of the inductor does not, AFAIK, affect the shape of the generated field.

Combinations of general terms 'interference' and 'magnetic' is not adding anything.

To give a better example of what I am fishing for: does the fluctuating magnetic field from the audio signal pulling on ferrous materials outside the conductor create non-linear resistance with magnitude of current? Do ferrous materials have slower changes in their induced magnetic fields because the domains keep their current alignment for a moment after current drops, and that has a some effect on the wires inductance or resistance?

Good tô see since your initial plain question you become an experiencied engineer.

[NoahH]

Alright - moving on to the adults in the room...

Anyone have any better insights here?

[S Clark]

Alright - moving on to the adults in the room...

Anyone have any better insights here?

I suggest that if you are going to argue with FullRangeMan that you do so in Portuguese, his native language.  Less misunderstandings. 

[NoahH]

I suggest that if you are going to argue with FullRangeMan that you do so in Portuguese, his native language.  Less misunderstandings.

I avoid judging on grammar for this reason - one rarely knows the backgrounds of those involved. Further, phone keyboards often result in typos.

I cannot, however, read "the mechanism is electromagnetism" as being anything but condescension. None of the responses after I clarified that I was looking for deeper commentary, and had a couple folks engaging nicely on deeper aspects, from him held any technical information.

The last note had literally no additional information or meritocratic content - it was purely mockery. I call that juvenile in any language.

I deleted a draft of my prior post that was not productive. I acknowledge and apologize that I still took the bait in any form including a short term.

I still am trying to return to the actual core question  of whether anyone has insight into the mechanisms causing degradation or other ill effects from ferrous metals in the signal path. Simply being correlated with poor conductivity is a good theory, and a form of hysteresis also would make sense, but I don't know what form that would be.

[S Clark]

Likely, the answer to your question is unknown. Some may take a theoretical stab at it, but I'd bet no one knows.  There are guys that are trying to sell snake oil, and then there are guys are simply going by what they hear.
Your ears may not agree with a position posited by Danny, and your ears are always right (always trust your own ears). But I'll swear that Danny's takes are based on what he hears.  He hears a negative impact of ferrous metals in the signal path.  Even my older ears do as well. 

[NoahH]

Likely, the answer to your question is unknown. Some may take a theoretical stab at it, but I'd bet no one knows.  There are guys that are trying to sell snake oil, and then there are guys are simply going by what they hear.
Your ears may not agree with a position posited by Danny, and your ears are always right (always trust your own ears). But I'll swear that Danny's takes are based on what he hears.  He hears a negative impact of ferrous metals in the signal path.  Even my older ears do as well.

I appreciate that. And let me clarify - I intuitively agree it should be a problem. And I have no issue if this is in the 'unknown' category - but I do want to press where I can for getting deeper.

Thanks for your thoughts here.