Humbuckers side by side : magnetic field continuity ?

[XLunacy]

Hello,

I'm working on a custom bass project, and currently focusing on the pickups and electronics.
I've learned a lot about the subject lately, but all this is still fairly fresh in my mind.

The bass will have 3 dual-coils side-by-side, and I'm wondering if the relative polarities of the pickups' magnets matter.

Is it somehow better to regroup the magnets together as much as possible, based on their polarity ?

Instinctively, it seems to me that it makes a lot of sense, but I can't find much information about this situation.
I do know that strats have the middle pickup RWRP, but I assume this is only done for hum-canceling purposes. In my case, each pickup is hum-canceling by himself so this should not be a consideration.

So basically, is any of these two configurations preferable to the other ? I've joined 2 pictures to explain the situation the best I could.

Thank you for your help !

 

[A9X]

As they're all HBs and not SCs then polarities all the same should be fine.

 

[XLunacy]

Thank you @A9X
Any other input ? I'd love to understand why these are equivalent !

 

[A9X]

I'd love to understand why these are equivalent !

I'm not sure what you're asking here.

 

[Jazz Ad]

If you plan to start switching phases it's going to be a giant mess. If you keep them as humbuckers, it won't matter.
I question the concept of using 3 identical closeby pickups though. Dingwall achieved something interesting out of it through specific switching but it's usually redundant.

 

[XLunacy]

I'm not sure what you're asking here.

I'm interested in understanding why the two configurations produce similar results, despite the obvious difference
There's this article, that essentially puts the string as the central component (and not the shape of the magnetic field), but it only takes one string and one pickup isolated in consideration : How Does a Guitar Pickup Really Work? | Guitar World

If you plan to start switching phases it's going to be a giant mess. If you keep them as humbuckers, it won't matter.
I question the concept of using 3 identical closeby pickups though. Dingwall achieved something interesting out of it through specific switching but it's usually redundant.

No phase switching, they'll always remain humbuckers series / parallel (considering the single coil option too !)
The rationale behind the design is to have as much flexibility as possible. I'd like to achieve a broad range of tones, and with specific switching I feel like this could work :
- single out each pickup (J bridge, J neck types of tones)
- combine any pair of pickups in series or blended parallel (MM bridge series / parallel, J bridge + neck blended)
- other interesting combinations (MM + J neck, and others)

I do know that there will be some redundance, but... Options You never know if you will like it unless you have the opportunity to try it.
I'll gladly create another thread to discuss the switching when I'm done with the design !

 

[A9X]

I'm interested in understanding why the two configurations produce similar results, despite the obvious difference

If all 3 are wired in phase at the summation point, ie the one with the reversed PU in the centre has it's wiring reversed, they are both electrically equivalent. This is for the first two you drew that are all HBs.

 

[Jazz Ad]

I'm interested in understanding why the two configurations produce similar results, despite the obvious difference

The difference is only obvious to you at this point.
Rotating a pickup doesn't change it's polarity or direction.
Why do you expect a change ?

J bridge, J neck types of tones
- combine any pair of pickups in series or blended parallel (MM bridge series / parallel, J bridge + neck blended)
- other interesting combinations (MM + J neck, and others)

Now wait. Do you plan to use different kinds of pickups together? This would change the whole thing.

 

[XLunacy]

You guys agree with each other, which is a good sign Thank you for chiming in.
When I see pickups I picture the lines running along the magnetic field. The 2 different configurations I posted do create two distinct magnetic field shapes, and I was thinking that these differences would translate into differences in sound ! Now I suppose, for a given point, the string is mainly influenced by the closest pickup, so these differences become negligible at the local level.

The difference is only obvious to you at this point.
Rotating a pickup doesn't change it's polarity or direction.
Why do you expect a change ?Now wait. Do you plan to use different kinds of pickups together? This would change the whole thing.

These would all be the same, to make things simpler.
I was giving specifics to provide the general idea of the target (getting close to a J bridge sound by having a single coil or parallel-wired pickup at the approximate location of a J bridge pickup).
This is all made under the assumption that the location of a given pickup is (one of) the most prevalent factor contributing to the sound, everything else being equal.
4 wire dual coil provide this option, and I know I won't be 100% there, but 80% is good enough for me, especially when you factor in the rest of the signal chain, and the context (other instruments, etc) ; the flexibility prevails to me !

I'll create a thread to discuss in detail the wiring and switching configurations that I have in mind, I'll ping you there since you seem interested

 

[ctmullins]

When I see pickups I picture the lines running along the magnetic field. The 2 different configurations I posted do create two distinct magnetic field shapes, and I was thinking that these differences would translate into differences in sound !

Nope. They do not create different magnetic field shapes. The left and right magnets in each pickup are identical. The two magnets will have opposite magnetic polarities, but the field shapes will be the same. The two halves of each pickup have essentially the same architecture, so they will behave identically.

In the six-string guitar world, there are some specialty pickups for which this isn’t true - for example, the Seymour Duncan P-Rail has two very different coils; one a P90 and the other a Strat-style rail. For a pickup like this, the orientation of the pickup does make a difference in tone.

 

[dwizum]

@XLunacy I think the thing you may be missing is that "north" and "south" are arbitrary designations for a magnetic field. If you drew the shape of the field around a magnet, the lines would look exactly the same regardless of which end was north or south.

The thing that creates a signal in your pickup is the strings moving in the magnetic field. The strings aren't polarized. They don't care which direction the field lines face. The signal generated is the same, regardless of which end is north or south.

A typical bass soapbar humbucking pickup that gets rotated 180 degrees is 100% equivalent in either orientation, magnetically and electrically. Rotating a single pickup doesn't make ANY difference whatsoever. That's for a single pickup, in isolation.

That said - I'm going to disagree with the other input you're getting - the two pictures you drew won't be equivalent, although I don't think the differences involved will be audible. Pickup magnets aren't selective, any magnet or conductive metal placed nearby can influence the field. When you start packing pickups really close to other pickups (and yours are drawn very close to each other), the magnetic fields interact. If you had intended to pack the pickups as close together as you have drawn them, the magnetic fields will be different between the two photos. The two drawings you've put in this thread will result in differences in the magnetic fields at the two "margins" on either side of the middle pickup. In your second picture, alternating poles, the field lines from the leftmost pickup will start to bend over towards the middle one as you bring them closer together. From the string's perspective, the field will get wider. In your first picture, with like poles together, the magnetic field lines will start to bend upwards and away from the other pickup as you bring them together. From the string's perspective, the field will get more narrow.

If you drew them that close out of convenience and had really intended to have them spaced out (as in the three pickups on a strat), it won't make a lick of difference, because the magnetic fields will be too far apart to influence each other.

Here's a cool simulator with two bar magnets:

https://iwant2study.org/lookangejss...gneticBarFieldsecondmagnet06_Simulation.xhtml

Look at the differences in the shape of the field between the magnets when you have like poles together (your first picture) or unlike poles together (your second picture).

Again though, the question really is: will it matter? I'm not sure if anyone can answer that, other than trying it out and letting us know. The strength of the field isn't going to be different. The coils aren't any different. There's a small difference in the shape of the field, but if I had to guess I'd guess that the difference is much smaller than you'd typically get between different pickup designs, even when staying within a given pickup style, which leads me to guess that you won't notice a difference.

 

[XLunacy]

@XLunacy I think the thing you may be missing is that "north" and "south" are arbitrary designations for a magnetic field. If you drew the shape of the field around a magnet, the lines would look exactly the same regardless of which end was north or south.

The thing that creates a signal in your pickup is the strings moving in the magnetic field. The strings aren't polarized. They don't care which direction the field lines face. The signal generated is the same, regardless of which end is north or south.

A typical bass soapbar humbucking pickup that gets rotated 180 degrees is 100% equivalent in either orientation, magnetically and electrically. Rotating a single pickup doesn't make ANY difference whatsoever. That's for a single pickup, in isolation.

That said - I'm going to disagree with the other input you're getting - the two pictures you drew won't be equivalent, although I don't think the differences involved will be audible. Pickup magnets aren't selective, any magnet or conductive metal placed nearby can influence the field. When you start packing pickups really close to other pickups (and yours are drawn very close to each other), the magnetic fields interact. If you had intended to pack the pickups as close together as you have drawn them, the magnetic fields will be different between the two photos. The two drawings you've put in this thread will result in differences in the magnetic fields at the two "margins" on either side of the middle pickup. In your second picture, alternating poles, the field lines from the leftmost pickup will start to bend over towards the middle one as you bring them closer together. From the string's perspective, the field will get wider. In your first picture, with like poles together, the magnetic field lines will start to bend upwards and away from the other pickup as you bring them together. From the string's perspective, the field will get more narrow.

If you drew them that close out of convenience and had really intended to have them spaced out (as in the three pickups on a strat), it won't make a lick of difference, because the magnetic fields will be too far apart to influence each other.

Here's a cool simulator with two bar magnets:

https://iwant2study.org/lookangejss...gneticBarFieldsecondmagnet06_Simulation.xhtml

Look at the differences in the shape of the field between the magnets when you have like poles together (your first picture) or unlike poles together (your second picture).

View attachment 4187899

View attachment 4187900

Again though, the question really is: will it matter? I'm not sure if anyone can answer that, other than trying it out and letting us know. The strength of the field isn't going to be different. The coils aren't any different. There's a small difference in the shape of the field, but if I had to guess I'd guess that the difference is much smaller than you'd typically get between different pickup designs, even when staying within a given pickup style, which leads me to guess that you won't notice a difference.

Wow, in-depth answer, thank you for that !

The picture is a realistic model of the configuration I intend to have (distances and dimensions at scale) ; so the pickups will be approximately this close to each other.

I do realize that the whole North / South is simply a convention, and that they are interchangeable for a pickup taken in isolation, but in a multi-pickup context, all the Norths are "the same" (same model, same manufacturer), which lead me to think about the interaction between them.
As you pointed out (played with the simulation a little, fun stuff ), the field shape changes quite a bit; your first picture (corresponding to my first configuration) looks a bit less "messy" IMO.
But as you said, hard to say how much this can affect the sound (objective), and in the case that it does, which configuration is the most pleasing, or even if one configuration is always "better" than the other (subjective).

So unless someone says otherwise, I'll probably stick with the simplest one, for cable managing and wiring simplicity reasons
I'm also trying to get manufacturers input on this, they should know

 

[NKBassman]

Just a thought not at all related to the specific subject at hand: If you're buying the pickups from a manufacturer (as opposed to making them yourself), the wiring will most likely be fixed at one end of the pickup, making it much more convenient to install in one orientation vs the other.

 

[dwizum]

If you're buying the pickups from a manufacturer (as opposed to making them yourself), the wiring will most likely be fixed at one end of the pickup, making it much more convenient to install in one orientation vs the other.

Try being left handed. You get real good at dealing with wires that come out of the "wrong" end of pickups. Luckily, I also make my own pickups, so I can make "left handed" versions with the wires at the "right" end when I'm making pickups for myself or other lefties, and I can put them at the "wrong" end for all you righties out there. TAKE THAT, UNIVERSE!

As you pointed out (played with the simulation a little, fun stuff ), the field shape changes quite a bit; your first picture (corresponding to my first configuration) looks a bit less "messy" IMO.

"Quite a bit" needs to be in context. As we've covered, the strings don't really care about the "shape" of the field, in terms of the direction the arrows are pointing. They care about the strength and the "size" in terms of the distribution of the field along the string (is there a narrow vs wide "sensing width"). The strength isn't going to magically change in your scenario - because the magnets are the same - and without seeing the density in that simulator it's hard to determine how much difference (if any) there will be in terms of how much the distribution of the field along the string will change. The part of the field that the pickup coils are in - look at the ring of arrows immediately around each magnet - isn't going to be really any different at all, except for having been rotated, which we've beaten to death as unimportant.

This would be a fun and very easy experiment, someone with a bass that has three pickup routes close together could tell us very quickly if they heard an impact by comparing your two scenarios. If I had such an instrument I would try this. But I don't.

I'd love to see if any of the pickup wizards or experimenters that hang out here and haven't chimed in yet have thoughts about this.

 

[XLunacy]

*patiently waiting for the pickup wizards*

 

[A9X]

*patiently waiting for the pickup wizards*

Why? You got your answer.

 

[XLunacy]

Why? You got your answer.

This is unnecessary, I do agree. But for the love of science, of course

This would be a fun and very easy experiment, someone with a bass that has three pickup routes close together could tell us very quickly if they heard an impact by comparing your two scenarios. If I had such an instrument I would try this. But I don't.

I'd love to see if any of the pickup wizards or experimenters that hang out here and haven't chimed in yet have thoughts about this.