Magnet Pull and Reduced Sustain

[kevinT]

I pulled this off of a site on the topic of magnets and their affect on the strings. Opinions please.

I am particularly interested in the concept of Nonlinear Distortions. ...Joe Gwinn please report to the OR.

"I do not believe in the magnet pull theory, this is a misinterpretation of magnetic effects. I don't think the high pickups actually make your string sustain much differently, it just sounds that way due to increased treble and increased nonlinear distortions due to the pickup's distorted view of the string's swings."

[David Schwab]

As you probably already know, I use neodymium magnets in my pickups. I have never found that the magnet reduces sustain. If the pickup is so close as to interfere with the string, you get that out-of-tune warble. And it has to be very close. I've actually had pickups that were not screwed down yet pop up and stick to the strings, but I haven't had any stop the string from sustaining.

I've mostly been doing bass pickups, and obviously the strings have a lot more mass than guitar strings, but that should make the effects of the magnet stringer, as it does on the low strings on a Strat.

[Joe Gwinn]

I pulled this off of a site on the topic of magnets and their affect on the strings. Opinions please.

I am particularly interested in the concept of Nonlinear Distortions. ...Joe Gwinn please report to the OR.

"I do not believe in the magnet pull theory, this is a misinterpretation of magnetic effects. I don't think the high pickups actually make your string sustain much differently, it just sounds that way due to increased treble and increased nonlinear distortions due to the pickup's distorted view of the string's swings."

The effect is called stratitis or wolf tones. What's happening is that the magnetic side pull is causing the string overtones (usually called harmonics, which is almost true) to become anharmonic (overtone frequencies departing from the traditional f, 2f, 3f, ... harmonic sequence). This is due to the physics of plucked strings, and has nothing to do with the pickup aside from the strength of the magnetic pull on the nearby string. Heavier strings (as for basses) are less affected, and the variation with distance between magnet and string is quite nonlinear, being far stronger at short distances.

I'd just try it with a handheld magnet and a guitar laying on a soft surface. Pluck a string and wave the magnet around, listening all the while.

I bet that a little bit of anharmonic behaviour is probably a good thing, to keep the sound from sounding sterile. Just like a bit of microphonics can be good.