Why do different magnet type produce different sounds?

[Antigua]

I've been getting frustrated with resources around the web that promise to explain the difference between AlNiCo 2, AlNiCo 3 and AlNiCo 5. They talk about how there are different balances of alloys, that some are magnetically stronger that others, then [magic goes here] and AlNiCo 2 ends up sounding softer, AlNiCo 3 has less string pull, and AlNiCo 5 is brighter and stronger... but none of them say why. I get the feeling none of them really know why since it never gets mentioned in the ten or so webpages I've looked, at and a book I've read all about pickup design. So there's sort of a black hole of information, because if you go the magnet experts, they can't tell you why AlNiCo 2 sounds different than AlNiCo 5 since they don't care about that, they care about it's industrial applications, such as heat tolerance, shock tolerance, coercivity, the ability to change polarity, form custom shapes, etc.

So why exactly does AlNiCo 2 usually sound softer than AlNiCo 5? If it's merely because it's weaker in strength, then why doesn't a degaussed AlNiCo 5 sound like an AlNiCo 2 in a given context? IME, a daguassed AlNiCo 5 actually sounds even brighter than a fully charged one, albeit weaker, but the point being, in the opposite direction of the AlNiCo 2, which confounds the notion that the difference in sound with AlNiCo 2 owes to a weaker field.

Does anyone know what specifically causes the various AlNiCo grades to perform differently, regardless of gauss?

Side question but equally important, apparently in Strat style pickup, with the AlNiCo being in the center of the coil, the magnet material has an impact on inductance since whatever is in the center of the coil will impact how the coil performs, whether it be a magnet, air, or something else, but when you swap magnetic bars on a humbucker, there's only ever steel in the coil's core, that doesn't change. Does this mean that swapping magnets on a humbucker will have no consequence on the inductance and Q factor, where as swapping magnets in Strat pickup it would?

[Mike Sulzer]

You mentioned differences from different permeability (inductance changes) and different field strengths. The only other factor is differences in conductivity altering eddy current losses. Alnico has small eddy current losses compared to steel, and I doubt that differences between the conductivities of different Alnico grades is very important.

[Chuck H]

You mentioned differences from different permeability (inductance changes) and different field strengths. The only other factor is differences in conductivity altering eddy current losses. Alnico has small eddy current losses compared to steel, and I doubt that differences between the conductivities of different Alnico grades is very important.

I should think there are MANY factors. One being that pickups have a dynamic impedance. Different magnets having different strength would exploit this property differently. Another would be how different magnetic materials affect the coil inductance. I hadn't considered eddy current losses, but I don't make pickups.

[Mike Sulzer]

I should think there are MANY factors. One being that pickups have a dynamic impedance. Different magnets having different strength would exploit this property differently.

What is "dynamic impedance" and and how would the strength of the magnet be involved?

Another would be how different magnetic materials affect the coil inductance. I hadn't considered eddy current losses, but I don't make pickups.

The effect on the inductance was already mentioned in both the initial post and the reply.

[Chuck H]

Really!? I can't reiterate when participating? You want to do this? You like this? You're a silly antagonistic person. And I'm not inclined to get into a discussion about what a dynamic impedance is or how different outputs under those conditions can affect sound only to play some stupid game where you focus on being intentionally contrary you pedantic chowder head. Unsubscribing now.

[big_teee]

The metal content in the difference magnets are different.
Apparently this has a lot to do with what they sound like.
See the chart.
Google Image Result for http://patentimages.storage.googleapis.com/WO2004002731A1/imgf000009_0001.png
**edit
Alnico 3, should be called Alnicu 3, because it has copper, but no cobalt!
Also, you can degauss A5 to the strength of A2, but IMO they still sound different.

[Antigua]

Apparently this has a lot to do with what they sound like.

"Why?" is the question. It seems as if nobody knows why A2 would sound darker than A5, for example. The reason I want to know is so that I can have a better understanding of exactly how the magnets contributes to the end result. People have been making decent pickups through trial and error alone for decades, it wouldn't surprise me if in fact nobody knows why an A2 results in a darker tone nine times out of ten.

[Antigua]

I should think there are MANY factors. One being that pickups have a dynamic impedance. Different magnets having different strength would exploit this property differently. Another would be how different magnetic materials affect the coil inductance. I hadn't considered eddy current losses, but I don't make pickups.

An answer to this question would clear this up: is the inductance of a coil influenced by outside magnetic fields, or is it only determined by what is physically within the coil's core? Maybe it's easier to ask the question this way, for any given inductor, not just pickups, do it's electronic properties change if a strong neodymium magnet is placed within it's vicinity?

[Mike Sulzer]

An answer to this question would clear this up: is the inductance of a coil influenced by outside magnetic fields, or is it only determined by what is physically within the coil's core? Maybe it's easier to ask the question this way, for any given inductor, not just pickups, do it's electronic properties change if a strong neodymium magnet is placed within it's vicinity?

A strong neodymium magnet placed very near the core could shift a core along its B-H curve. If such a curve is, well, curved, rather than straight, that could alter the permeability and thus the inductance. (A similar example is this: if you make a strat type pickup with unmagnetized rods, and then magnetize them, you can see some change in the inductance measured before and after magnetization because the magnetization moves the operating point along the B-H curve, changing the permeability enough to matter. This is noticeable because the permeability of Alnico is moderately low, but easy to shift along the curve.)

[Mike Sulzer]

"Why?" is the question. It seems as if nobody knows why A2 would sound darker than A5, for example. The reason I want to know is so that I can have a better understanding of exactly how the magnets contributes to the end result. People have been making decent pickups through trial and error alone for decades, it wouldn't surprise me if in fact nobody knows why an A2 results in a darker tone nine times out of ten.

Permeabilities of different types of Alnico do vary. Thus the inductances vary, and a larger inductance could result in a darker sound.

[Mike Sulzer]

Really!? I can't reiterate when participating? You want to do this? You like this? You're a silly antagonistic person. And I'm not inclined to get into a discussion about what a dynamic impedance is or how different outputs under those conditions can affect sound only to play some stupid game where you focus on being intentionally contrary you pedantic chowder head. Unsubscribing now.

I think you are upset because you have no more idea what "dynamic impedance" means when applied to a pickup than I do. You disagreed with my statement, which is fine. But justifying your disagreement with BS deserves to be called out.

[Antigua]

Permeabilities of different types of Alnico do vary. Thus the inductances vary, and a larger inductance could result in a darker sound.

Is that only true when the magnet is in the coil's core? In a PAF pickup, the different magnets are outside of the core.

A strong neodymium magnet placed very near the core could shift a core along its B-H curve. If such a curve is, well, curved, rather than straight, that could alter the permeability and thus the inductance. (A similar example is this: if you make a strat type pickup with unmagnetized rods, and then magnetize them, you can see some change in the inductance measured before and after magnetization because the magnetization moves the operating point along the B-H curve, changing the permeability enough to matter. This is noticeable because the permeability of Alnico is moderately low, but easy to shift along the curve.)

Do you know if that would that require an especially strong magnet, or will a weaker AlNiCo beside the coil effect inductance as well, to any significant degree?

I think where we're at is that AlNiCo 2 produces a different sound than AlNiCo 5, and it can't be attributed to strength because a degaussed A5 sounds substantially different than an charged A2, and it can't be attributed to differences in inductance, because in the care of a PAF, the magnet is outside of the core, so process of elimination cancels out two of the more obvious explanations, and maybe leaves the possibility that that there is something special about the nature of the magnetic field itself that is or is not conducive to communicating high frequencies from the strings to the coils. This would be especially true if there is in fact a difference between smooth and roughcast magnets, or beveled versus flat pole pieces, because in either case the difference is purely with respect to the magnetic field itself, no electronic property of the coil. Is it possible that the magnetic field produced by and AlNiCo 2 bar is somehow qualitatively different than the magnetic field produced by AlNiCo 5?

[pdf64]

I read somewhere (may have been Seymor Duncan blurb) that A5 had a narrow intense focussed mag field, whereas that of A2 was more diffuse and spread out; so the sensing window on the string is different, affecting the harmonic content, eg a wider window would result in more cancellation.
BS?

[Jazz P Bass]

"dynamic impedance"?
I thought that the term was applied to diodes.

[big_teee]

"Why?" is the question. It seems as if nobody knows why A2 would sound darker than A5, for example. The reason I want to know is so that I can have a better understanding of exactly how the magnets contributes to the end result. People have been making decent pickups through trial and error alone for decades, it wouldn't surprise me if in fact nobody knows why an A2 results in a darker tone nine times out of ten.

You know that you're just going to get opinions, and it really doesn't matter.
So I will say, if you read the chart it is because it has more aluminum, and more nickel, and less cobalt.
So next I ask are you jumping forum to forum on this?