Pole length on pickup and it's effect

[sirmuppet]

So I'm wondering this. If I had a pikcup where the middle poles were longer than the outer poles would the effect the sound? By this I mean I have a Jazz bass pickup which has poles that are radiused. So the middle poles are actually physicall longer than the outer poles. If I were to set the string height flat and push the middle poles down flat, would they still have a stronger pull given that the poles are magentic and physically longer than the outer poles?

 

I wonder this based upon the mass of the inner pole being larger and would that affect the magnetic pull?

 

Hope that made sense but it was just something that crossed my mind while I played a Jazz bass last night. 

[sirmuppet]

Here's a diagram I just made to illustrate my question.

 

 

 

Edited April 6, 2023 by sirmuppet

[itu]

The distance is the key word here. You move the poles further away from the strings, the magnetic field diminishes, and the signal becomes fainter.

 

I was about to write that the sound becomes fainter, but that can be adjusted by amp gain. Make trials to hear the difference in sound.

[sirmuppet]

3 hours ago, itu said:

The distance is the key word here. You move the poles further away from the strings, the magnetic field diminishes, and the signal becomes fainter.

 

I was about to write that the sound becomes fainter, but that can be adjusted by amp gain. Make trials to hear the difference in sound.

Cool. I was hoping that was the case. I just wasn't sure if a larger mass would add to the magnetic field or not. Good to know it doesn't. Thanks for answering. 

[BigRedX]

Do you know that the poles are longer? Or are they just in a slightly different place in relation to the coil?

 

Is each pole an individual magnet or do they all share a common magnet along the base (in which case you could argue that there are no individual poles and that the the whole magnet/pole assembly acts as a single unit.

 

Time to read some proper science texts I think.

[itu]

I am not quite sure, what is @BigRedX after here? I did make an educated guess that the magnets are from the same batch, although they are different in length OR some poles are adjusted to different height and the main magnet is uniform. I would be very much surprised to hear that magnets of different strength would be selected to E, A, D, and G string on any mass produced pickup. But I know that you can buy bigger batches that are of certain strength, because I worked with magnets some years ago.

[Bunion]

On 06/04/2023 at 12:36, sirmuppet said:

If I were to set the string height flat

Why would you do this? You set the height to follow the radius of the neck.

 

 

[Andyjr1515]

Screw slugs on electric guitar pickups are much more common than on basses (although you do see them on both) and are generally used to balance the volumes across the strings.  But, in essence, yes, the closer the poles are to the strings, the stronger the signal and therefore the volume.  And, to a lesser extent, the tone can be affected too.

 

However, as far as my experience goes, the distance of the main pickup coil to the strings has a much larger impact on signal strength than that of raised poles.   

[PaulThePlug]

^ For Info... I don't think the pole piece 'screws' on Entwistle P and J pickups are actually adjustable... wouldn't recommend trying in case you damage the windings.

 

Edited April 8, 2023 by PaulThePlug

[Andyjr1515]

Like all these kinds of things, @PaulThePlug, never try these sorts of things unless you are sure, but generally a screw slug is fitted for just that. 

 

On a standard coil the slugs are nowhere near the windings.  The windings are usually round a plastic bobbin and the slug holes are drilled in the centre of the bobbin.  That said, they can be very stiff to turn at first because the hot wax they are generally dipped in holds them firmly - and many a guitar and bass top has been scratched by an errant screwdriver slipping on a suddenly released screw.  So good advice not to do it unless you are sure, but for a slightly different reason 

 

[Andyjr1515]

Love the diorama, by the way 

[sirmuppet]

On 07/04/2023 at 23:54, Bunion said:

Why would you do this? You set the height to follow the radius of the neck.

 

 

You wouldn't. It was an example for simplicity.

[sirmuppet]

On 07/04/2023 at 08:32, BigRedX said:

Do you know that the poles are longer? Or are they just in a slightly different place in relation to the coil?

 

Is each pole an individual magnet or do they all share a common magnet along the base (in which case you could argue that there are no individual poles and that the the whole magnet/pole assembly acts as a single unit.

 

Time to read some proper science texts I think.

Yup the middle poles are physically longer than the outer ones. 

 

Each pole is a magnet, no bar pn the bottom. 

[sirmuppet]

14 hours ago, Andyjr1515 said:

Screw slugs on electric guitar pickups are much more common than on basses (although you do see them on both) and are generally used to balance the volumes across the strings.  But, in essence, yes, the closer the poles are to the strings, the stronger the signal and therefore the volume.  And, to a lesser extent, the tone can be affected too.

 

However, as far as my experience goes, the distance of the main pickup coil to the strings has a much larger impact on signal strength than that of raised poles.   

This isn't what I'm trying to clarify. I was looking to know if the size of the pole if larger but the same distance and a smaller pole (Both magentic) has an impact or if they'd just be the same magnetic pull. 

[sirmuppet]

On 07/04/2023 at 23:17, itu said:

I am not quite sure, what is @BigRedX after here? I did make an educated guess that the magnets are from the same batch, although they are different in length OR some poles are adjusted to different height and the main magnet is uniform. I would be very much surprised to hear that magnets of different strength would be selected to E, A, D, and G string on any mass produced pickup. But I know that you can buy bigger batches that are of certain strength, because I worked with magnets some years ago.

It's not a mass produced pickup. The inner pole are physically longer. I just wanted to know if I set the height the same and the distance was the same would the mass of the magnetic pole have an impace or not.

[sirmuppet]

14 hours ago, PaulThePlug said:

^ For Info... I don't think the pole piece 'screws' on Entwistle P and J pickups are actually adjustable... wouldn't recommend trying in case you damage the windings.

 

I'd seen this post already. Shame as they could have been cool. 

[itu]

1 hour ago, sirmuppet said:

It's not a mass produced pickup. The inner pole are physically longer. I just wanted to know if I set the height the same and the distance was the same would the mass of the magnetic pole have an impace or not.

You should read about magnetic inductance: when a metal part (string) moves in a magnetic field surrounded by a coil, it creates voltage to the coil. The voltage is dependent on the amount of wire in the coil and magnetic field.

 

Voltage can be increased by making the field more powerful (move the string closer, or use another magnet), or putting more wire to the coil. This has also other effects: a bigger coil reduces the frequency response (EMG has less wire, and has wider response, although faint signal). Very powerful magnet would affect string movement.

 

Coil magnet pickup is a BPF (band pass filter), as it doesn't go down to DC, and is limited up to, say 4 - 5 kHz. Piezos and light based pickups can reach much wider response, but require a bit more complex electronics. This equals higher price, which one certain Leo didn't like.

[sirmuppet]

8 hours ago, itu said:

You should read about magnetic inductance: when a metal part (string) moves in a magnetic field surrounded by a coil, it creates voltage to the coil. The voltage is dependent on the amount of wire in the coil and magnetic field.

 

Voltage can be increased by making the field more powerful (move the string closer, or use another magnet), or putting more wire to the coil. This has also other effects: a bigger coil reduces the frequency response (EMG has less wire, and has wider response, although faint signal). Very powerful magnet would affect string movement.

 

Coil magnet pickup is a BPF (band pass filter), as it doesn't go down to DC, and is limited up to, say 4 - 5 kHz. Piezos and light based pickups can reach much wider response, but require a bit more complex electronics. This equals higher price, which one certain Leo didn't like.

Again this is not directly the question I'm asking. I know how pickups work and moving cloers etc.. Normally pickups tend to have the poles the same length. With mine the middle poles are longer than the outer ones. All I'm asking is would a longer magnet at the same distance as a shorter magent produce the same field? As in does "mass" affect it in anyway?

[tauzero]

1 hour ago, sirmuppet said:

Again this is not directly the question I'm asking. I know how pickups work and moving cloers etc.. Normally pickups tend to have the poles the same length. With mine the middle poles are longer than the outer ones. All I'm asking is would a longer magnet at the same distance as a shorter magent produce the same field? As in does "mass" affect it in anyway?

 

I'm not sure how useful this answer is, but the strength of neodymium magnets varies with their size. I see what you're saying, but the magnet material will presumably make a difference as will how they are magnetised. If the issue is relative loudness of strings, I'd suggest experimentation.

[itu]

At the moment I think you believe that a certain family, like AlNiCo represents certain "power level", although an AlNiCo magnet can be as weak as a plastic rod.

 

The size does not only dictate the magnet, there are many parametres starting from the materials and the production process. There will be tolerances, too. Magnets are produced in big batches: you can ask what are you after, and the factory can find the right products for you.

 

If you make an order of two magnets that are only slightly different in size, they can be ordered with the same "power level".

 

As I said earlier, Neodymium can be magnetized far weaker than an AlNiCo, or SmCo, or a simple ferrous magnet, although it can be the most powerful of these few families. This depends on the production process and the need.

 

Am I clear enough, do I answer your questions?

 

(The pickup itself seems to be ordinary, although you say it is special made. Do you want to open it up a bit?)

[Baloney Balderdash]

16 hours ago, itu said:

At the moment I think you believe that a certain family, like AlNiCo represents certain "power level", although an AlNiCo magnet can be as weak as a plastic rod.

 

The size does not only dictate the magnet, there are many parametres starting from the materials and the production process. There will be tolerances, too. Magnets are produced in big batches: you can ask what are you after, and the factory can find the right products for you.

 

If you make an order of two magnets that are only slightly different in size, they can be ordered with the same "power level".

 

As I said earlier, Neodymium can be magnetized far weaker than an AlNiCo, or SmCo, or a simple ferrous magnet, although it can be the most powerful of these few families. This depends on the production process and the need.

 

Am I clear enough, do I answer your questions?

 

(The pickup itself seems to be ordinary, although you say it is special made. Do you want to open it up a bit?)

I am pretty certain that the basic point of the OP is following:

 

If you got 1 magnet of a certain given strength, then cut/split it, so that you now got 2 magnets, but not exactly in half (50/50), but lets say one piece is 60% the size of the original magnet and the other piece is 40% of the original magnet's size, will the two pieces then have exactly equal strength or will the piece that is 60% of the original magnet be stronger than the piece that is only 40% of the original magnet, given the strength is measured from a given isolated identical surface area, say the two ends respectively at which they were cut from the bigger original magnet?

 

Edited April 10, 2023 by Baloney Balderdash

[itu]

Dear Baloney, I think your comment includes the original, although a theoretical question. But magnets are produced in big amounts and the tolerances already dictate the strengths. Magnetizing - which has also tolerances - produces components that are then selected to represent certain specs.

 

A magnet is not ideal, because materials and production methods are not ideal. There's no one magnet that represents all similar sized magnets, except that it's more or less magnetic.

[ikay]

As itu says, there are many factors involved in the strength of the magnetic field in any given magnet. However, I think the simple answer to the original post is probably yes. If the poles are of the same material and charged in the same way for the same length of time, the longer magnet contains more magnetic material (domains) that can be aligned and therefore the potential to produce a slightly stronger field. In practice the difference is probably negligible. The proximity of the magnet to the vibrating string will have a much greater effect on the strength of the signal being produced. The purpose of the longer D and A poles is to do exactly that, by compensating for the curvature of the fretboard and therefore the D and A strings being higher above the pickup.

 

https://sciencing.com/causes-different-strengths-magnets-5981925.html

Does the size of a magnet affect its strength? The short answer is yes, but only because the size of a magnet means that there are proportionally more domains that can align and produce a stronger magnetic field than a smaller piece of the same material.

[fleabag]

By the way, the screws on Entwistle neo pickups dont actually screw the pole up and down.  You can simply push the poles up and down. The 'screw' appears to

be cosmetic only

[PaulThePlug]

^ Same as on the Ceramics... Star Wars pic above...

The Screw is the metal slug, and not threaded in to anything.

Edited April 10, 2023 by PaulThePlug