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

[nickb]

Strong magnetic force between string and PU increases the frequencies of fundamental and harmonics for up and down string movement but not for sideways vibration. The result is beating and dissonance, aka. stratitis. Damping can only occur if the PU is loosely mounted and actually vibrates.
I have not seen any evidence of increased string damping yet.

Thanks for that fascinating tidbit

I can see why the two axes are affected differently, but what I cannot see is why the change in frequency. Can you explain a bit further?

[Chuck H]

Thanks for that fascinating tidbit

I can see why the two axes are affected differently, but what I cannot see is why the change in frequency. Can you explain a bit further?

You're leading him

[Chuck H]

Of course the pickup moves due to string vibration pushing on the pickup magnets. And of course it's a very small amount of movement. But small isn't none. At guitar amp gain levels I'll bet the affect isn't insignificant.

[Helmholtz]

Thanks for that fascinating tidbit

I can see why the two axes are affected differently, but what I cannot see is why the change in frequency. Can you explain a bit further?

The magnetic force varies with string excursion and makes the string react somewhat stiffer for up-and-down movements, thus increasing the strings' resonant frequencies in this plane. Sideways vibrations don't "see" much change in magnetic force during excursion and are far less influenced. The PU mainly responds to up-and-down vibration, but as the two othogonal vibrational modes exchange energy, a beating effect caused by the slightly different frequencies is produced, which shows in the envelope of the signal decay. The effect is strongest in the neck position.

This effect has been analyzed in detail by Professor Zollner and I think Antigua's measurements also show this.

[Helmholtz]

Of course the pickup moves due to string vibration pushing on the pickup magnets. And of course it's a very small amount of movement. But small isn't none. At guitar amp gain levels I'll bet the affect isn't insignificant.

If the PU vibration is caused by the magnetic interaction with the string, the result is increased damping/less sustain. I have no data for quantitative evaluation.

[nickb]

The magnetic force varies with string excursion and makes the string react somewhat stiffer for up-and-down movements, thus increasing the strings' resonant frequencies in this plane. Sideways vibrations don't "see" much change in magnetic force during excursion and are far less influenced. The PU mainly responds to up-and-down vibration, but as the two othogonal vibrational modes exchange energy, a beating effect caused by the slightly different frequencies is produced, which shows in the envelope of the signal decay. The effect is strongest in the neck position.

This effect has been analyzed in detail by Professor Zollner and I think Antigua's measurements also show this.

Thanks.

I had figured out most of it. It was just the imperfectness of the spring changing the resonant frequency I missed.

[Antigua]

Of course the pickup moves due to string vibration pushing on the pickup magnets. And of course it's a very small amount of movement. But small isn't none. At guitar amp gain levels I'll bet the affect isn't insignificant.

You're suggesting that the pickup movement might create an overtone addition to what is there otherwise. First, I don't see a credible claim that it leads to an overtone, I only see a credible claim that it could cause a reduction in sustain, because the moving pickup would serve as a damper; the rubber or string mounts that allow the pickup to move up and down slightly would be the agent of damping. But the mechanical coupling between the pickup and string is very, very low, and the pickup's mass is many times greater than that of the strings, so the degree to with the pickup could reduce the sustain through that mechanism is very, very, very small.

Even if there was an overtone that the amplifier could bring to prominence through gain, it would be drowned out by everything that is of much higher amplitude. Imagine you have an audio recording of a crowd talking, with some faint voices in the background and some loud voices up front. What you're suggesting is that if you just cranked up the gain on this audio, you'd be able to clearly hear what the faint voices in the background were saying, but we all know that's not what ends up happening.

[Helmholtz]

..so the degree to with the pickup could reduce the sustain through that mechanism is very, very, very small.

Yes, but the additional energy loss required for a little more string damping is also very, very small.
The vibrational energy of a body is proportional to its mass times the oscillation amplitude squared for a given frequency. This means the higher the mass, the lower the amplitude for the same energy content. Consequently the vibration of the PU will be hardly noticeable without special equipment (e.g. a laser-vibrometer). Also the PU will transfer/lose energy to connected parts (springs, pickguard etc.) further reducing its vibration amplitude.

Apart from that, where else could the energy loss go, if there is actually a damping effect caused by strong magnets?

[Chuck H]

But the mechanical coupling between the pickup and string is very, very low, and the pickup's mass is many times greater than that of the strings, so the degree to with the pickup could reduce the sustain through that mechanism is very, very, very small.

I keep seeing this mentioned, BUT...

The pickups mass being greater than the string is only significant if they are left to their own inertia. The string is at considerable tension and YOU pluck the string to disturb that tension. How far would a pickup move if you plucked it? My point is that the vibrating strings lower mass is considerably countered by energy. Consider that a 12 ga. bird shot load weighs a lot less than a pumpkin and perhaps reconsider the equation

EDIT: I guess for the "physics" guys I should have said "the vibrating strings lower mass is considerably countered by velocity." Resulting in the significant energy needed to impact the circumstances. Past experience has taught me that I'd better correct this here before I get flamed as a matter of semantics

[nosaj]

I keep seeing this mentioned, BUT...

The pickups mass being greater than the string is only significant if they are left to their own inertia. The string is at considerable tension and YOU pluck the string to disturb that tension. How far would a pickup move if you plucked it? My point is that the vibrating strings lower mass is considerably countered by energy. Consider that a 12 ga. bird shot load weighs a lot less than a pumpkin and perhaps reconsider the equation

I like your backwoods analogy. there chuck like a comet pinging the earth or maybe a meteorite. Which some should be in view this evening.

nosaj

[Antigua]

I keep seeing this mentioned, BUT...

The pickups mass being greater than the string is only significant if they are left to their own inertia. The string is at considerable tension and YOU pluck the string to disturb that tension. How far would a pickup move if you plucked it?

The pickup will barely moved at all, no matter how you frame it.

My finding, which can be seen in the screen shot I posted a few posts back, and this is something that anyone with a Strat can try for themselves, is if you put the neck pickup so close to the strings that "Stratitus" sets in, the relative amplitude drops off more quickly than when the pickup is set lower. So it appears to me it's not a question of if it happens, it's a question of why, and the idea that the pickup itself servers as a damping agent seems very far fetched, due to the pickup's relative immobility. Not only is the pickup many times heavier than the strings, but it's attached to a guitar, which is many times heavier than the pickup.

Eddy currents are a more plausible cause of damping, and that's the same principle on which eddy current breaks work with trains and power tools (here's a demo https://www.youtube.com/watch?v=mopfuVfeIhc ) There again, the degree of coupling between the string and pickup is very low compared to an actual eddy current break, but maybe it's just strong enough to dampen the string movement over a long duration of time.

My point is that the vibrating strings lower mass is considerably countered by energy. Consider that a 12 ga. bird shot load weighs a lot less than a pumpkin and perhaps reconsider the equation

I'm pretty sure the damping ratio is independent of the amplitude, at least within the range of what a damping system can handle. A shot gun delivers a force that exceeds the operational range of most systems, such as pumpkins.

[Helmholtz]

The OP has informed me that he " decided to discontinue posts and other discussions about this topic".

[Antigua]

The OP has informed me that he " decided to discontinue posts and other discussions about this topic".

That doesn't mean the topic isn't still of interest to others.

[Antigua]

Yes, but the additional energy loss required for a little more string damping is also very, very small.
The vibrational energy of a body is proportional to its mass times the oscillation amplitude squared for a given frequency. This means the higher the mass, the lower the amplitude for the same energy content. Consequently the vibration of the PU will be hardly noticeable without special equipment (e.g. a laser-vibrometer). Also the PU will transfer/lose energy to connected parts (springs, pickguard etc.) further reducing its vibration amplitude.

Apart from that, where else could the energy loss go, if there is actually a damping effect caused by strong magnets?

Maybe there is an "eddy current break" thing happening, the more I think about it, the more curious I'm becoming about it. It's a weak effect, because spread out over a period of several second, maybe significant. You're knowledgeable in physics and I'm curious what you think about the potential of eddy current breaking working to resist movement of the guitar string.

[J M Fahey]

The OP has informed me that he " decided to discontinue posts and other discussions about this topic".

- Own Opinions Only -

Do I see a contradiction here?

or:

if the OP feels he has something to say, he is warmly invited to do so ... all by himself