Lowest magnetic pull with a reasonably efficient pickup

[Fluoroscope 5000]

I follow the reasoning. It doesn't seem plausible given that magnets pull the string regardless of the orientation, and there would be no significant interaction in the string at such distances. I'm not sure what would happen if the opposing magnets were side by side. The field would run more horizontally within the string between the poles, but each magnet would still pull the string, init? That could be tested as well. Also, the claim that a difference is heard with both pickups engaged would have more to do with the relative reduction of higher harmonics from a wider aperture and the harmonic cancellations between the two points. Post 311 seems to imply that the magnetic field produced in the string only becomes active when the pickup is engaged. The fields and any modulations created in the string by them are there regardless if the pickups are engaged, or together reproduce them more or less obviously in the output – at least that's how I understand it. There's a good bit of supposition in that post that I am attempting to disprove. Tests would be more effective, but a compass will react to the fields emanating from either magnet regardless of the presence of strings, so I don't think it would be helpful.

[Antigua]

The only "reliable" info can find on the notion that RW/RP helps or hinders Stratitus, or otherwise has any audible effect whatsoever, aside from the Seymour Duncan Q&A, is a book written by Donald Brosnac, originally authored in 1983, revised as recently as 2011, but it's not he who originated the information, he quotes Seymour Duncan https://books.google.com/books?id=hf...larity&f=false

Several other Google hits refer back to the Johnny Marr video, and he says Tim at Bare Knuckle Pickups is the one who told him polarity can have an audible effect on the strings. Maybe Tim did tests of his own and found this to be true, but it also wouldn't surprise me if Tim had read a book called "Guitar Electronics for Musicians" at some point in his life. This is to suggest that, though this contention has been repeated on the internet, it seems to originate from few sources, such as Seymour Duncan and maybe Tim Mills.

But there's problem, in the Johnny Marr video, he claims that Tim believes non-RWRP produces a better tone:

https://youtu.be/_HQQSYa7nDg?t=5m47s

but Seymour Duncan says the opposite:

301-325 - Seymour Duncan

The overtones are due to each pickup having the same polarity (3 South or 3 North Polarity). ...As the magnetic field from the center pickup travels down the string, the magnetic field is repelled by the two outside pickups. As the like poles repel each other down the string, the overtones become very distorted sound wise. ... reversing the magnetic polarity in the center pickup will help reduce magnetic repulsion in the string.

Frankly, I don't see how this is supposed to work, how do you have magnetic repulsion "in" the string, how strong is that repulsion, and why/how does it even matter?

The strings had several areas where the string was trying to repel the magnetic field within it.

The string is trying to "repel" itself? Wat? What vectors are we talking about? This is all very non-technical exposition, especially:

Than I remembered in science class that like magnetic fields repel and opposite magnet fields attract.

Like "oh yeah! that's how these little things work..."

Also, there's some curious verbiage on the Seymour Duncan Q&A

The strings had several areas where the string was trying to repel the magnetic field within it. This would cause the string to have an inaudible overtone that got worse as you moved up the fingerboard.

Inaudible overtone? As in, "cannot be heard" ?

[Mike Sulzer]

Let's review the physics. A magnet near a string induces magnetization in it. (This is ferromagnetism we are talking about. Paramagnetism is a weaker effect of the opposite sign.) For energy reasons, the magnetic dipoles in the string try to line up with those in the magnet: not anti-line up; they try to point in the same direction. To the extent that they line up, you have south poles in the string pointing towards north poles in the magnet, or north and south if the magnet is pointed the other way. Thus you always have attraction, and it only occurs close to the magnet. As has been pointed out, there is no effect which travels along the strings.

So, what does this attraction, this force between the string and magnet do?

First, a string is a resonator with various modes corresponding to the various harmonics. It is a mechanical resonance, relying on force and the momentum of moving mass. You can of course find many references describing this. The key issue here is that there is a restoring force: if you pull a string aside, you stretch it, and it pulls back. The stronger the restoring force, the higher the frequency of oscillation. The more mass in the string, the lower the frequency. If you move a strong magnet close to a string, you can feel the force between the magnet and string getting stronger. The string, of course, feels the opposite force.

So when the string vibrates, its distance from the magnet varies, and the varying force between the string and magnet adds to the restoring force from stretching the string. it tends to weaken the restoring force, and so it can affect the frequency of the string. It could also encourage the production of more harmonics, but the exact result of this only a physicist could like to determine.

The restoring force is not modified significantly when the string moves parallel to the magnet, and thus there would appear to be two different frequencies of oscillation! What really happens? This is complicated, and again, only a physicist could love finding the result, but anyone can hear what happens, and it is not very attractive.

[jack briggs]

First, a string is a resonator with various modes corresponding to the various harmonics.

Mike,

Don't you mean "nodes"?


cheers,

[Mike Sulzer]

Mike,

Don't you mean "nodes"?


cheers,

Certainly there are nodes, but I am using 'mode' to designate each type of oscillation. Thus you could say: each mode of oscillation (harmonic) has its own set of nodes.

[Antigua]

The restoring force is not modified significantly when the string moves parallel to the magnet, and thus there would appear to be two different frequencies of oscillation!

It sounds like you're describing Stratitis in general, and it's an insightful and easy to understand technical breakdown at that, but what is your take on the somewhat difficult-to-parse explanation from Seymour Duncan that RW/RP can help reduce Stratitis?

301-325 - Seymour Duncan

311. How do I get rid of that dissonant overtone in my Strat pickups when playing notes on the lower strings at the higher frets?

Lowering the neck and middle pickup on the bass side of the strings helps reduce the “Strat-ites”. I remember needing a pickup for the center position of an old Strat and I ended up putting an old Duo-Sonic pickup that was reverse wound and reverse polarity (RW/RP) from the existing bridge and neck pickups. I found that when I put the lever switch in the two and four position of a normal 3 or 5 way lever switch the two positions became quieter and I noticed that the dissonant overtones on the lower strings was reduced. I used a Boy Scout compass and noticed that each pole piece on the pickup magnetized the string with the same polarity and would repel as I moved the compass in between the neck and middle pickup and the middle and bridge pickup. Than I remembered in science class that like magnetic fields repel and opposite magnet fields attract. The strings had several areas where the string was trying to repel the magnetic field within it. This would cause the string to have an inaudible overtone that got worse as you moved up the fingerboard.

323. What is "Strat-ites"?

Often caused when the height of the pickup is adjusted close to the strings and dissonant overtones are heard as you play further up the frets. It is really noticeable as you play on the bass strings way up the fingerboard. The overtones are due to each pickup having the same polarity (3 South or 3 North Polarity). The string acts like a keeper but is magnetized in three locations. As the magnetic field from the center pickup travels down the string, the magnetic field is repelled by the two outside pickups. As the like poles repel each other down the string, the overtones become very distorted sound wise. The Strat-ites can be reduced by lowering the pickups on the bass side of the pickups. Also reversing the magnetic polarity in the center pickup will help reduce magnetic repulsion in the string. The notes will have a clearer sound as you play up the frets. The string can have several magnetic fields that react with the pickups magnetic field.

Someone on another forum had something funny to say about this idea

http://guitarnuts2.proboards.com/thr...-polarity-tone

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?

[Mike Sulzer]

I do not disagree with the comment you quoted; but I very much like SD pickups, and I prefer to appreciate the good, rather than emphasize the negative.