Slant Pole Pieces

Sound probably depends more on other factors (wire gauge, winding, magnets...). But the slant gives a slightly wider aperture, and that can matter too. I’m just not sure how much the slant contributes to the sound by itself...

 

The magnetic field is less even (more concentrated around the strings' rest positions) when you put the pole pieces next to each other like that - they share that with 51 P bass pickups (the 51 P bass pickup is more extreme in its concentration of magnetic field). That would give you more low order distortion (2nd and 3rd harmonic) products when the string is moving a lot than with a more even field - that aspect is probably more audible in a neck position pickup. That said, I have Nordstrands twisted pole pickups in the bridge position on a couple of my basses - I like them there. I don't think it's necessarily because of the twist, though - they're just good pickups that sound good to my ears as bridge pickups.

 

It's difficult for me to put it into words, but Nordstrand calls it Character on their timbre charts for their pickups.
The Big Singles have the slanted poles & they have heaps of character!

I've gotten used to them now, but when I first heard & played the Big Singles they were nothing like I'd heard before & I was in turtle dove.
Recently I played my SR1800E exclusively for a few days while I waited on my beater bass to come back from the luthier & when I plugged in the beater I remembered why I love those Nordstrand's so much!

This is not to say the beater sounds bad, in fact it sounds great to me, but it's lacking that top end & high-mids sparkle.
Possibly to be solved soon with some new coated stainless steel strings:

 

String spacing might be an issue with these. In addition to the magnetic field being a bit less smooth, if you are using end to end hum cancelling pickups, and you bend a string between the two halves of the pickup (bending the D string on a 4 string towards the A string for example), there can be, with focused magnetic poles, a "magnetic valley" when the string goes rather quiet. I had issues with this on a 51 (wired for hum cancelling) style pickup. I don't have those issues with J style pickups wired for hum cancelling (wider spaced magnets seem to help a lot) - they have a bit of a valley if you bend the D string a lot on the neck pickup, but I don't bend that much. With split coil P pickups, the valley seems non-existent, even if I go out of my way to bend a ridiculous amount - wider pole spacing and the offset seem to both help, as fart as I can tell.

 

I don't think .5 mm off center would give you issues - there's more than enough aperture there to cover you. A couple mm, maybe, but 1mm or less, I think you'd be good.

 

Interesting topic.

@Llewellen , when Haeussel specified a 17mm minimum spacing, that could be interpreted (at least) two different ways:

• Due to pickup construction limitations, the focus of each magnetic subassembly can be no closer than 17mm from its neighbor, or
• The set of pickups can accommodate string spacings of no less than 17mm at the bridge

Do you happen to know which they mean?

 

The spacing issue seems to be related to the split coil design, not the slant of the poles. Having two poles per string, slanted or straight, limits how much room there is for wire. To allow the appropriate number of turns of wire (per coil), they need to keep at least 17mm string spacing. So I don't think either of their designs with two small poles per string will align with your string spacing. That said, it might work sufficiently well.

I would, however, clarify with them what they mean with "17 mm spacing". It is not clear what they mean, and if they mean 17 mm at the bridge, then their neck pickup might indeed be narrower and fit just fine.

 

Seems like slanting the pole pieces is one way to give them a larger working area due to the overlap angle without increasing the actual diameter of the pole pieces.

Slanting may also have some effect on the geometry of the magnetic field.

What that translates out to in terms of timbre and transfer characteristics is something I have no way of assessing since I lack the design background. But it does sound interesting enough that I’m now thinking about trying some.

 

This sounds like my experience with Nordstrands. It's just a somewhat fatter sound, with more mids. Haeussel doesn't seem to have such an extreme slant, so I imagine the impact on sound is smaller.

It's also similar to the Nordstrand description (for Fat Stacks): "The traditional bi-pole magnet layout was rotated 45 degrees, increasing the size of the traditional J style coil by 50%, making the coil wider and instigating the growth of a larger magnetic aperture, facilitating the capture of each string's unique harmonic characteristics. This results in a fatter tone..."