About Magnetic Polarity and Tone

[col]

Hi,

I just watched an interview with Johnny Marr on Youtube about his Signature Jaguar. At just past 8:00 into the video, Marr explains that his two pickups have the same polarity, so that, 'like a Telecaster' the strings 'are not being pulled in two different directions'. He claims this makes big difference to the sound.

I can understand a theoretical difference, but would two pickups with opposite magnetic polarity really affect the vibration of the strings enough to make a noticeable difference to the sound?



Thanks.

[yakkmeister]

I don't think so.
There is a potential for the different polarity to make a difference electronically but I don't think the flux would extend far enough down the string to cause a problem magnetically.
But then, I don't really know - Just guessing.

[reTrEaD]

Hi col!
Interesting hypothesis Johnny has, eh? waddaya say we dissect it?


"so that the strings are not being pulled in two different directions."

1 - Do the magnets in pickups pull on the strings? YES.

2 - Is this a bad thing? Well it ain't great. But as long as the pull is minor we can live with it. Use extremely strong magnets or put them very close to the strings and you get Stratitis.

3 - If the strings were being pulled in two different directions by the two pickups, would this be worse than having them both pull in the same direction? I'm not absolutely certain, but I think not.

4 - (here's where it really falls apart) Will having opposite polarity on the magnets pull the strings in two different directions. NO!

The strings are NOT magnets. They have no inherent polarity. They aren't attracted by one polarity and repelled by the other. They are made of an alloy that is affected by magnets. So a magnet can pull on the string and it doesn't matter whether the end of the magnet that is closest to the string is North or South, it will pull the string in the SAME direction -- toward the pickup.

5 - Does the pickup magnet, magnetize the string. Yes. But only in a fairly local region. If the magnet is south up, the side of the string closest to the magnet will have a north polarity and the side farthest from the magnet will have a south polarity. Will the magnetized region near the bridge pickup affect the magnetized region near the neck pickup? Let me answer that question with another question ... If you spit in the ocean, does sea level rise?



Conclusion:
I suspect Johnny has spent too much time talking to his cousin Nigel.

[sumgai]

Paging Dr. reTrEaD, Paging Dr. reTrEaD! Cleanup on Point Number 5, please!!

Apr 29, 2012 6:28:57 GMT -5 reTrEaD said:

5 ...... If the magnet is south up, the side of the string closest to the string will have a north polarity and the side farthest from the string will have a south polarity.
 

[col]

Hi,

Yes, it was point 5 where I thought there would be a theoretical effect, but I too could not imagine it having an audible effect. I doubt that it even could be measured electronically.

I don't think there would be a pole induced on the 'opposite side of the string', but, rather, along the string. So, I would expect there would be some tiny imperceptible difference if two like poles were induced locally near the two pickups, compared to two opposite poles.

So, it would appear that the Marr Guitar is just noisier. That's a shame.

[col]

I meant, the pole induced along the string would be opposite to the pole induced locally, directly in front of the pickup.

[reTrEaD]

Apr 29, 2012 12:52:01 GMT -5 sumgai said:

Paging Dr. reTrEaD, Paging Dr. reTrEaD! Cleanup on Point Number 5, please!!

grrrrr. That'll teach me about posting before my morning coffee. Edits in red.

Apr 29, 2012 13:48:19 GMT -5 col said:

So, it would appear that the Marr Guitar is just noisier. That's a shame.

But it will be less noisy when he puts the pickups out of phase with each other. Oh wait, he doesn't have a switch for that. Nevermind.