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Author
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Topic: Vertical vs. horizontal string vibration
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David Mason
Member From: Cambridge, MD, USA
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posted 14 September 2006 05:31 AM
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Is there some real, genuine, technical scientific explanation why a string that's vibrating sideways seems to sound so much fuller than a string that's vibrating vertically (perpendicular to the pickup?) I've been using fingerpicks on a regular electric six-string some and the tone can get thin - I noticed that when I really consciously tried to make the string vibrate horizontally the sound fattened up, and when I plucked them UP it thinned out. I then got all research-y on my steel (to alleviate the effect of the fretboard) and it still seems to happen - I did try to control for equal volume, distance from the pickup etc. Is it something to do with the magnetic field, or am I just tripping again? Obviously this would have some bearing on how you bend your fingerpicks, and the type of motion you try to make with them. |
Ray Minich
Member From: Limestone, New York, USA
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posted 14 September 2006 07:26 AM
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Has to do with the string cutting the magnetic lines of force. Imagine the magnetic lines of force come out of the pickup polepieces vertically. If the string is vibrating vertically the string is moving parallel to the lines of force and not "cutting" them. If the string is vibrating horizontally the string is moving at 90 degrees to the lines of force and "cutting" them at "maximum", inducing the maximum electromagnetic effect.
I can't remember if it's the left hand rule, the right hand rule, or the chicken mcnugget rule but it's in the usual physics books. |
Jim Palenscar
Member From: Oceanside, Calif, USA
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posted 14 September 2006 07:35 AM
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An interesting side note to this is that, when using the RTA (Real Time Analyser) program that Ed Packard, Joe Meditz, and I used recently at my shop in measuring the wave outputs of various guitars, we found that pickups with pole piece magnets had a greater output when the string was plucked in a horizontal fashion (side to side) than when the string was plucked in a vertical fashion (up and down- toward and away from the pickup). Interestingly enough- the inverse was true when measuring the output of bar magnet pickups. |
Joseph Meditz
Member From: San Diego, California USA
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posted 14 September 2006 11:31 AM
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quote:
Has to do with the string cutting the magnetic lines of force. Imagine the magnetic lines of force come out of the pickup polepieces vertically. If the string is vibrating vertically the string is moving parallel to the lines of force and not "cutting" them.
Not quite.
It is the magnetic flux lines cutting across the coil in the pickup that generates the voltage. The presence of a steel string changes the shape of the magnetic field as compared to that of the magnet alone. And when the string moves it moves the magnetic flux lines. So, the way the string causes a voltage in the pickup is not by cutting the magnetic lines of force but by moving them. Joe |
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