Bobbin shapes, don't the E/e strings have an "advantage" ?

[Meowy]

Using your typical 6 string in standard tuning and given the shape of a typical bobbin, be it a humbucker coil, a strat / tele single coil or a P90, the E/e strings expose to a greater coil sensing area.

Not only are they in proximity to the part of the coil that runs alonog the edge of the bobbin form, but also the area that wraps around the ends.

In other words, the strings that are not at the ends of the bobbin are in proximity to two parallel and opposite sides of the coil, but the strings at the extremes are in proximity to a larger and continuous "U" (or if you prefer "C" shape) of the coil form.

Does this have any practical or theoretical effect on output, tone, balance, muddiness, brittleness, etc?

[pilotjones]

I've wondered about this too. It seems to me that this would cause the inner strings to be mostly (and exclusively on blade pickups) sensitive to vertical movement (perpendicular to the fretboard), but that the outer strings would get an added dose of side-to-side sensitivity. I'd like to know if this is true in practice.

[Jay Mitchell]

I've been working on a pickup design for use with Strats. Based on the behavior of the prototypes I've built, I've been led to do some thinking about how the vibrations of a ferromagnetic material alter the magnetic field. My hypothesis at this point is that the string shorts across lines of flux, and that the motion of the string changes which lines are being shorted, and therefore the intensity of the magnetic field surrounding the windings. If this is correct, it means that sensitivity to string vibration is maximized when lines of flux are in the same plane as the string, and minimized when they are in a plane that is at right angles to the length of the string.

Even though there is a greater total winding length near the ends of a pickup, this would be offset, at least partially, by the fact that the lines of flux at the end are not entirely parallel with the string. If you draw curved N-S lines from the top of the polepiece to the bottom (or from the top of one polepiece to the top of its "sibling" in a humbucker), I think you'll see what I'm talking about.

[David Schwab]

This is exactly what the two Bartolini patents cover. Because he had flat topped pole tips. he got an even low flux pattern that was parallel to the top of the pickup. He felt this brought out more of the up and down motion of the strings, and less of the side by side, which resulted in more of an acoustic type of tone.

I think it should also be noted that on a Strat style pickup, the outer two strings don't have the flanking magnets the way the inside stings do. I think the field affects the coil as a whole though, which is why the outer two strings don't sound different.

[Joe Gwinn]

This is exactly what the two Bartolini patents cover. Because he had flat topped pole tips. he got an even low flux pattern that was parallel to the top of the pickup. He felt this brought out more of the up and down motion of the strings, and less of the side by side, which resulted in more of an acoustic type of tone.

Bartolini has the theory spot on.

I think it should also be noted that on a Strat style pickup, the outer two strings don't have the flanking magnets the way the inside stings do. I think the field affects the coil as a whole though, which is why the outer two strings don't sound different.

The falloff of the outer strings is due to leakage flux at the edges of the polepieces. The locations of the coils is unimportant, because steel has ~1000 time the magnetic permeability of air, so the pole-piece bars in effect short the magnetic field and funnel it through the coil cores, regardless of where those cores may be.