Is it possible to accurately describe the tone of magnets and/or pickups?

[ric]

String vibration damping requires a loss/transfer of energy. While a strong magnetic field/attraction between string and PU may shift string frequencies for the Y-motion and might increase PU distortion, I don't see a possibility for a damping effect as long as the PU itself doesn't start vibrating.

Are there any measurements showing PU field induced string damping?

A fixed magnet next to a vibrating steel string. How can that Not have a damping effect?

I ask from a "isn't that just common sense?" perspective. I don't have any scientific or engineering background.

I'll be interested to see how this plays out.

[Helmholtz]

The mass of the bass strings are high enough to be more damped if the pole piece were too large or strong and located directly below the string.

String vibration damping requires a loss/transfer of energy. While a strong magnetic field/attraction between string and PU may shift string frequencies for the Y-motion and might increase PU distortion, I don't see a possibility for a damping effect as long as the PU itself doesn't start vibrating.

Are there any measurements showing PU field induced string damping?

[bbsailor]

I was thinking the same thing. But then I thought, what if that's not all there is. Is it possible that there is some difference in delivery of magnetism as it relates to the bounce back/beating of the string? I ask because I honestly don't know. What I mean is, do some magnetic materials yield/recover more/less in the presence of another magnetic force? This would certainly change the feel and tone. I thought of this because alnico speakers have a reputation for being more compressed sounding when driven hard. I haven't used enough alnico speakers to report on it. Maybe it's bunk, but a lot of guys are spending three times for the alnico speakers what their ceramic counterparts cost for some reason.

Here is another view of this issue. Consider the direction of the initial string motion relative to the pole piece locations. In a P bass or J bass pickup the string lies between two pole pieces per string. The mass of the bass strings are high enough to be more damped if the pole piece were too large or strong and located directly below the string. With two smaller pole pieces on each side of the string, any horizontal movement will induce a magnetic pulse in the coil at each end of the horizontal string motion thus emphasizing the second harmonic more than if only a single pole were mounted directly below the string. Emphasizing the second harmonic in a bass makes them sound “less muddy” based on comments about their sound.

How we perceive sound occurs mostly in the first 30 millivolts seconds of the initial attack, especially when playing live with other instruments.

Here is a simple experiment to do to hear the result of string movement. Pinch a string between your fingers right above the neck pickup. Pull sideways about .125 inches and release. Listen and/or look at an oscilloscope image of this and look at the relative output of the primary frequency versus the second harmonic at twice the frequency. Now, do this again in the same place over the pickup but this time pinch the string and raise vertically and release. This motion will produce a stronger fundamental output with a more asymmetrical output because on the downward motion of the string it is closer to the magnet while at the upper most string location, it will be in a weaker magnetic field. Try this with the string location located between two magnetic poles and observe and listen to the differences.

This string motion relative to pole piece locations is a topic that does not get much discussion but based on the comments in this thread, it might be time to discuss this.

When you add the other typical characteristics of the pickup, such as resonance, Q at resonance, loading by on board controls and effect of coax capacitance on overall performance, you can now see if second harmonic emphasis due to pole placement were in line with resonance characteristics, there could be an emphasized interaction that can now be better understood and added to the discussion.

Joseph J. Rogowski

[Chuck H]

Magnets do not have tonal properties; they have magnetic and electrical properties, which contribute to the sound of the pickup in combination with the other components of the pickup. For example they have a magnetic field strength, electrical conductivity, and magnetic permeability.

I was thinking the same thing. But then I thought, what if that's not all there is. Is it possible that there is some difference in delivery of magnetism as it relates to the bounce back/beating of the string? I ask because I honestly don't know. What I mean is, do some magnetic materials yield/recover more/less in the presence of another magnetic force? This would certainly change the feel and tone. I thought of this because alnico speakers have a reputation for being more compressed sounding when driven hard. I haven't used enough alnico speakers to report on it. Maybe it's bunk, but a lot of guys are spending three times for the alnico speakers what their ceramic counterparts cost for some reason.

[Mike Sulzer]

Magnets do not have tonal properties; they have magnetic and electrical properties, which contribute to the sound of the pickup in combination with the other components of the pickup. For example they have a magnetic field strength, electrical conductivity, and magnetic permeability.

I appreciate the suggestions but don't think folks have a clear understanding of what I am asking.

I made some quick measurements on single isolated Alnico pole pieces that will address some of the comments. The pole pieces measure 0.187 (+/- .001) x 0.671 and have very different tonal properties. I have made a number of Strat sets (with similar winding parameters) from each material and gotten feedback on their tonal properties both professional and amateur musicians. At the present time the most skilled blues player I know (over 45 years of professional experience) has neck and middle pickups from each material in two hybrid (tele bridge and strat neck/middle) teles. He likes both, recognizes that there are significant differences in their tonal properties but is unable to describe the differences beyond saying that one of the materials "sounds more like a 57 strat" than the other.

My measurements show the difference in field strength between the two fully magnetized poles to be less than 5% and I find it hard to believe this difference to be large enough to account for the nature and size of the tonal differences between the two materials.

This conclusion is further supported by an experiment in which I added a 0.032 thick x 0.188 dia. unmagnetized disc of Alnico 3 to the bottom of one pole and repeated the field measurement. The disc had virtually no effect on field strength even though past experience has shown that attaching them to the bottom pole surfaces of a fully magnetized strat pickup will significantly alter its tone.

All the available experimental evidence (and I have accumulated a lot over the past 9 years) indicates that the tonal differences that are observed in samples of the same alloy from different manufacturers are due to variations in ferromagnetic loss. These losses also contribute significantly to observed tonal differences in the soft ferromagnetic materials that are commonly used to make humbucker slugs, screws and keeper bars. In all cases they are sensitive functions of composition, the methods used to cast the materials, and the details of their thermal and mechanical histories. Samples from different foundries vary significantly with respect to one or more of these parameters.

I don't think it is possible ( or reasonable) to measure the differences in ferromagnetic loss directly but do think it should be possible to describe their effect on pickup tone using reasonably precise terminology. Terms such as 'like a PAF' or 'similar to a '57 strat' get used a lot but have poorly defined meanings.

[David King]

You could do "waterfall" plots of the same pickup with different mags installed and see if you can "see" any differences in the plots. You would need identical plucks.

[Antigua]

I made some quick measurements on single isolated Alnico pole pieces that will address some of the comments. The pole pieces measure 0.187 (+/- .001) x 0.671 and have very different tonal properties. I have made a number of Strat sets (with similar winding parameters) from each material and gotten feedback on their tonal properties both professional and amateur musicians. At the present time the most skilled blues player I know (over 45 years of professional experience) has neck and middle pickups from each material in two hybrid (tele bridge and strat neck/middle) teles. He likes both, recognizes that there are significant differences in their tonal properties but is unable to describe the differences beyond saying that one of the materials "sounds more like a 57 strat" than the other.

These observations are not solid enough to be actionable. In order to derive an objective conclusion from a survey, you need a lot more than one source of feedback, so that it can be said that what you conclude is true of many different people, and not one person. Also, if you're testing magnetic effects, it would be crucial that absolutely everything else is controlled, meaning the same coil is used, and the height of the pickup in relation to the strings never changes. In general, it is so difficult to assure that all of these things are accounted for that it's not merely enough to say that you have accounted for them, I'd expect a detailed description of the process by which you accounted for them. If you do none of this, then in all likelihood there will be some experimenter's bias at play, and I can only assume that the outcome you report is the outcome you had wanted from the beginning.

[Antigua]

In a way, I actually see value in your blues player friend's feedback. Without any absolute measurement, tone is more efficiently compared than described.

You can have an absolute measurement in the form of FFT analysis, in a controlled setting. It's not that it can't be done, it's that very few people ever have done it. I've done some testing of this sort, and witnessed that magnetic strength causes variations at different harmonic levels, and that the differences were not linear, which is to say that when the magnet is stronger, you don't just get "more" of something, but entirely different effects emerge at different harmonic levels, depending on the degree of disruption caused by the magnet. At one extreme, the string ring naturally as if there was no pickup in the guitar, while at the other, you get "wolf tones" or "Stratitus", and then there is everything in between, which constitutes the various "flavors" you get with different magnets and different pickup height settings.

[Helmholtz]

The small loop hysteresis losses vary with position on the demagnetization curve.

I am not sure about this. Is there any measurement data or literature supporting this? Generally the losses caused by magnets are very low, especially in relation to other causes. And the recoil permeability doesn't change much with charge.

But there are also other effects:

- Professor Zollner found that PU aperture is influenced by the field strength at the strings' positions. Higher fields shorten the aperture, which allows higher string harmonics to be picked up.
- I found that replacing the weak magnets (450G) in a P-90 type PU by stronger ones (700G) reduced the PU's inductance by over 10%.

[epizootics]

In a way, I actually see value in your blues player friend's feedback. Without any absolute measurement, tone is more efficiently compared than described. When mixing a track, you often see experienced sound engineers using an already mixed track as reference point, because they know that even their ears aren't a 100% reliable after listening to a work in progress many times. Some mixes aren't objectively harsh, they are only so compared to other mixes. One gets used to hearing certain types of sound, which is related to musical genre, what gear was available and what was fashionable at that time, etc. So in a way, your friend is giving you the most honest and accurate answer possible.

As for investigating the impact of using magnets from different manufacturer on the 'tone', as JM Fahey suggests, you would have to repeat the tests a few dozen times to get any results of scientific value, but there are still far too many variables to take into account, at least far more than six. You would also have to compare magnet samples from the each manufacturer with themselves to test the internal variations of their production.

This is all written from the humble point of view of a guy whose scientific background is that of a 'soft' science, ie. psychology. There are lots of guys here who come from 'harder' sciences who I'm sure will be more to the point. But in a way, the study of the human mind feels as slippery a terrain as that of tone. One can either look into a phenomenon with one's common sense & inductive processes, which are not without worth as they will be close to the thinking of the consumer, or study that phenomenon with a proper experimental framework, which takes time and resources. There is sadly not much value to anything in between those two and it can become very depressing to realize you've spent a lot of time, money and efforts on a biased experiment. We're not saying you can't do it, we're just saying that you need to do it very carefully and understand what such a study entails.

[J M Fahey]

So - to restate my original question in clearer terms:

Is it possible to describe the tonal qualities of different magnets using a few (<6) perceptual variables??

Very short answer?: no.
For the very good reason that nobody knows what those variables would be.

If so, what variables would you use????

Dunno, you tell us, it´s your theory and investigation.

I appreciate the suggestions but don't think folks have a clear understanding of what I am asking.

You don´t seem to have a clear understanding either, your question is still too vague and undefined.

I made some quick measurements on single isolated Alnico pole pieces that will address some of the comments. The pole pieces measure 0.187 (+/- .001) x 0.671 and have very different tonal properties.

Well, you say so and I believe you, and probably *listening* to them we could find differences ... or not .... but if not even you can describe differences clearly ..... what can we do at the other end of a screen?

I have made a number of Strat sets (with similar winding parameters) from each material and gotten feedback on their tonal properties both professional and amateur musicians. At the present time the most skilled blues player I know (over 45 years of professional experience) has neck and middle pickups from each material in two hybrid (tele bridge and strat neck/middle) teles. He likes both, recognizes that there are significant differences in their tonal properties but is unable to describe the differences beyond saying that one of the materials "sounds more like a 57 strat" than the other.

Ok. If even such an experienced player, who *uses* them, can not describe differences, and to boot only by the vaguest most undefined and unmeasurable terms, what do you expect us to do?
And you want us to come up with 5 or 6 variables? Wow!!!!

My measurements show the difference in field strength between the two fully magnetized poles to be less than 5% and I find it hard to believe this difference to be large enough to account for the nature and size of the tonal differences between the two materials.

Doubt that is the only difference and everything else is exactly the same.

This conclusion is further supported by an experiment in which I added a 0.032 thick x 0.188 dia. unmagnetized disc of Alnico 3 to the bottom of one pole and repeated the field measurement. The disc had virtually no effect on field strength even though past experience has shown that attaching them to the bottom pole surfaces of a fully magnetized strat pickup will significantly alter its tone.

Ok, keep experimenting.
Use different magnets: a whole one, another 90:10 , another 80:20 , and so on, make a table showing results, then make an hipothesis and verify it with further experiments. That´s the Scientific method.

[QUOTE]All the available experimental evidence (and I have accumulated a lot over the past 9 years) indicates that the tonal differences that are observed in samples of the same alloy from different manufacturers are due to variations in ferromagnetic loss.
Ok. so you do have a Theory.
Now experiment and confirm/discard/correct it. That´s the way to go.

These losses also contribute significantly to observed tonal differences in the soft ferromagnetic materials that are commonly used to make humbucker slugs, screws and keeper bars. In all cases they are sensitive functions of composition, the methods used to cast the materials, and the details of their thermal and mechanical histories. Samples from different foundries vary significantly with respect to one or more of these parameters.

Cool, now repeat experiments but show results in table form.
Otherwise it´s only light talk.

I don't think it is possible ( or reasonable) to measure the differences in ferromagnetic loss directly

Hey!!! WHY not!!!
If it´s the basis of your Theory, then you MUST experiment changing that variable and showing results in a table form.

but do think it should be possible to describe their effect on pickup tone using reasonably precise terminology.

No "terminology" will ever be more precise than actual measurements, whth results shown in an ordered/compiled form.

Terms such as 'like a PAF' or 'similar to a '57 strat' get used a lot but have poorly defined meanings.

You bet, and that´s exactly my point, glad you agree.

I suggest you continue with your experiments, and show results in an ordered way.

[Tone Cam]

I appreciate the suggestions but don't think folks have a clear understanding of what I am asking.

I made some quick measurements on single isolated Alnico pole pieces that will address some of the comments. The pole pieces measure 0.187 (+/- .001) x 0.671 and have very different tonal properties. I have made a number of Strat sets (with similar winding parameters) from each material and gotten feedback on their tonal properties both professional and amateur musicians. At the present time the most skilled blues player I know (over 45 years of professional experience) has neck and middle pickups from each material in two hybrid (tele bridge and strat neck/middle) teles. He likes both, recognizes that there are significant differences in their tonal properties but is unable to describe the differences beyond saying that one of the materials "sounds more like a 57 strat" than the other.

My measurements show the difference in field strength between the two fully magnetized poles to be less than 5% and I find it hard to believe this difference to be large enough to account for the nature and size of the tonal differences between the two materials.

This conclusion is further supported by an experiment in which I added a 0.032 thick x 0.188 dia. unmagnetized disc of Alnico 3 to the bottom of one pole and repeated the field measurement. The disc had virtually no effect on field strength even though past experience has shown that attaching them to the bottom pole surfaces of a fully magnetized strat pickup will significantly alter its tone.

All the available experimental evidence (and I have accumulated a lot over the past 9 years) indicates that the tonal differences that are observed in samples of the same alloy from different manufacturers are due to variations in ferromagnetic loss. These losses also contribute significantly to observed tonal differences in the soft ferromagnetic materials that are commonly used to make humbucker slugs, screws and keeper bars. In all cases they are sensitive functions of composition, the methods used to cast the materials, and the details of their thermal and mechanical histories. Samples from different foundries vary significantly with respect to one or more of these parameters.

I don't think it is possible ( or reasonable) to measure the differences in ferromagnetic loss directly but do think it should be possible to describe their effect on pickup tone using reasonably precise terminology. Terms such as 'like a PAF' or 'similar to a '57 strat' get used a lot but have poorly defined meanings.

[John_H]

Is it possible to accurately describe the tone of magnets and/or pickups?

With all of the variables already discussed, it's pretty easy to recognize that any measurements taken would be questionable. Tone is subjective, but describing tone in it's basics isn't difficult. Describing in accurate terms the differences between Brand X, and Brand Z's A5 humbucker bar magnets wouldn't be so easy. Start with the hard data that you can measure. Take accurate measurements, and gauss readings. I'm sure there are some differences.

[bbsailor]

The actual difference that is made is in terms of how much the pickups pulls on the strings magnetically. The effect can't be summed up with typical tone words because the changes vary depending on which position the pickup is in, and they vary by how far the pickup is set from the strings, and the changes differ by harmonic level. The string is divided up into harmonics nodes and anti nodes, and so the harmonic effects depends on how close the pulling force is to an anti-node, and how strong the magnetic pull happens to be. The more pull there is at an anti-node, the more that specific harmonic will be disrupted. The strong the pull, the complicated things get. Because there is so much change at different harmonic levels, it's almost more of a difference in timbre than it is tone, and timbre is much harder to describe, like describing the difference between a piano and an acoustic guitar.

Also, it is how and where you strum relative to the turned on pickups(s). Guitars typically have a second harmonic peak for the first part of the initial attack and this can be controlled by pick thickness and picking style sort of like the subtle sounds made by speech and singing. Strings are just another type of vocal cord. Once the strings rotate from their initial horizontal motion through the strum, the strings will rotate to their normal motion and the initial second harmonic of sideways motion will get less as the string starts to decay.

The only truly scientific way to test this is to automatically pick the string in the same place relative to the pickup and change pickups and magnets and compare the observable differences and then what you hear. String damping, even by a small amount, can be heard as a loss in sustain even if the pickup is not turned on.

Joseph J. Rogowski

[Antigua]

I have been trying to come up with a system for describing the tonal properties of magnets of the same alloy that come from different suppliers. It is obvious that a variable describing overall EQ (bright vs. dark, or bass,middle,treble balance) is needed and a second variable that quantifies the density of harmonics (fat vs thin?) would be useful. It also seems important to have a variable that describes how smooth or harsh the tone is at high frequencies and possibly a fourth that deals with how open (vs. compressed) the tone is.

It would also be useful to have a similar system for pickup tone. A few established pickup makers have attempted to describe their products with variables like EQ, output level and 'attack' but these descriptions seem to leave out a lot of important tonal information.

Is it possible to accurately describe the tone of magnets and/or pickups with a few (<6) key variables?

The actual difference that is made is in terms of how much the pickups pulls on the strings magnetically. The effect can't be summed up with typical tone words because the changes vary depending on which position the pickup is in, and they vary by how far the pickup is set from the strings, and the changes differ by harmonic level. The string is divided up into harmonics nodes and anti nodes, and so the harmonic effects depends on how close the pulling force is to an anti-node, and how strong the magnetic pull happens to be. The more pull there is at an anti-node, the more that specific harmonic will be disrupted. The strong the pull, the complicated things get. Because there is so much change at different harmonic levels, it's almost more of a difference in timbre than it is tone, and timbre is much harder to describe, like describing the difference between a piano and an acoustic guitar.