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Main Description
Bar magnets for humbuckers
These magnets are commonly used in Humbuckers and P90s to charge the steel poles; however, whilst they do turn up in other applications, I’ll speak pretty much entirely about Humbuckers in this, because, frankly, that’s the common use of the things.
They’re orientated, polished magnets, supplied precharged to their maximum gauss (strength) and they are the 62mm long magnets, which were used up to 1960 (after that, historically, humbuckers switch to the 58mm version)
These are the sand cast magnets, which were used originally, and have a rough surface, and some imperfections in the external shape/dimensions. Honestly, i doubt they effect the tone of a pickup what so ever when compared to the more modern polished magnets, but for historic builds? If your going to do it, you might as well be doing it right!
Available in Alnico 2 and 5, and compatible with most 6 string humbuckers.
Sound Clips
How the sound changes
Now, we’ve been putting a lot of work into magnet testing over the years, and, honestly? There’s a lot of fuss made about Alnico grade, the supposed inferiority of ceramic magnets, the merits of orientated vs. unorientated, the benefits of sand cast vs. rough. Vs polished… so, we figured we’d be as open and honest about it as we can be – so, here goes!
Lets start with the bode plot - pretty easy to get your head around - the line shows how "strong" a signal the pickup is generting at a certain frequency - so the higher the line, the stronger that frequency. (so a higher line in the low frequencies means a bassier pickup, a pickup with a higher line in the treble means brighter - a wider "peak" (where the pickup is busiest) means a smoother pickup, a sharper "peak" means a more defined pickup. Simple as that.
So lets get into it - have a play! Compare your magnets!
Tonally, and specifically, I’m speaking about “how the guitar sounds” – honestly? Magnets don’t actually do a great deal believe it or not – when presented with the “full spectrum” of a guitars signal, the minor variations that are evident when comparing one magnet to the next, are just too subtle to for our ears to be able to pick out. If you listen to a recording of an Alnico 3 and compare it to the same piece on an Alnico 8, you’ll struggle to be able to hear any difference what so ever.
However - there actually are tonal difference! It’s just that, in terms of “what we hear” – they’re a little buried under all the information we’re being bombarded with when we listen to audio.
As a general rule of thumb, the weaker the magnet, the more “bass” its producing – and that’s about it – which gives some real credibility to the old wives tale of “weaker magnets sound warmer” – BUT – a magnet is only one variable within the construction of a humbuckers.
I can definitely say that its true for a vintage humbuckers (tested here with an 8.2K Bourbon City, 42 AWG coils, 12 screw coils) – however – when we take the same test, and apply it to a “high output” humbuckers (in this case a 16K Ethereal, 12 screw, 44 AWG coils) – we see that all of the magnets behave pretty much identically with the exception of Alnico 8 and Ceramic (which are often described as “scooping mids”… and that’s actually what they’re doing – they show a volume drop below the resonant peak, but retain the same volume above it!... so again, some truth to the myth!)
So, electrically -we definitely CAN see that the magnets are changing the signal of the pickup – but we’ve got to take this with a pinch of salt, because the coils are actually changing how the magnets are behaving – and that leave us in a strange position where the “hard and fast rules” quickly fall down dependant on a second (or third!) variable! (Which honestly, gets a little beyond the scope of this article) – But remember – when you’re listening to a pickup as a recording, you really won’t be able to tell the difference. I can’t stress that enough! The differences are there, but our ears aren’t good enough to isolate them. It’s that simple.
It’s all in the feel!
HOWEVER – as guitarists, we’re not really interested in how the guitar sounds “on record” (that’s for the studio engineer right?!) – We care about it as a “live thing”, which we respond to, and feel, and generally treat as a very unscientific thing right? (Dare I say, a musical instrument?!) And that’s where things get interesting.
Whilst we might not be able to actually hear a difference between one magnet and the next in retrospect, we certainly can feel it when playing! In the moment, as pick hits string and the amp roars into life, the differences are much more noticeable! And what the graphs show, actually comes through more in the “feel” of a pickup then it does in the recordings. (So, that Alnico 3 Bourbon City felt “muddy”, and that Alnico 8 Ethereal did feel very defined and cutting) I honestly, can’t say I know why, but in blind tests, we were able to highlight differences between magnets – we had combinations we liked, and we had combinations we didn’t.
This brings us to the crux of the matter really – magnets within a humbuckers have very little to do with “tone”, but they really do define the “feel” of the pickup – and, sadly, there’s no right or wrong answers at that point, because we’re speaking about perception – and that’s going to differ for every single person, with every single humbuckers.
Me, for example – I heard the following in the blind tests with the Bourbon City. (Please, excuse the romantic language – these are exactly how the notes were written)
Alnico 3 – Very glassy in the highs, very bloomy in the lows, quite mushy and unpleasant.
Alnico 2 – Huge amount of top end “ping”, bass neat and tidy, plenty of “spank”, a little weird but not unpleasant! (Slightly damning considering the Bourbon comes with an A2 as standard!)
Alnico 4 – Toppy, really soft and forgiving in the bass, mids are rich and interesting. Nice sound.
Alnico 5 – Strong bass, but quite neat and tidy, not an awful lot of mids, and quite chimy. A lot of rattle and definition.
Alnico 6 – tight in the bass, quite crunchy, not overly hot. Nice note separation.
Ceramic – more compressed, better balances, distance between tops and bass is pleasing, slightly lacking in top. Bass very well behaved. Raunchy and fun!
You get the idea – I had “opinions” when playing! Unscientific they may be, but it’s what I “felt” and what is telling, is that my opinions? The “feel” I got from each magnet? They don’t really correspond with the signal we know the pickup is producing!
Alnico 3 does, that increase in bass is definitely coming through as mud and the ceramics certainly show that decrease in bass… but I’m “feeling” things in the pickup that just aren’t in the graphs right?
Well… no – what I’m feeling, comes down to perception – and this is where things start to become a little bit confusing, but basically, we don’t need to hear a change in a specific frequency to actually perceive a change in that frequency. (So, a pickup can feel bassier if the high frequencies are reduced – the bass doesn’t change, but our ears “shift” to become more focused) – And seemingly, even minor shifts in certain frequencies can completely colour our perception of frequencies that haven’t even changed.
Conclusion? Sort of?!
At this point, me sitting here and saying “Alnico 2 does thing, and Alnico 3 does that!” is nonsense, because I’m describing “how it made me feel” more than “how it actually sounded”, and how you feel with a particular magnet (or combination of Magnet and Coil!) will be completely different.
But if theres anything to take away from this, it’s the following “rules”
1.Go into Humbucker magnets knowing that your unlikely to be able to “hear” a difference between any of them, but you’ll definitely be able to feel it!
2. “Vintage” humbuckers (anything wound with 42 AWG) is going to show bigger difference then “high output” winds (43 and 44 AWG)
3. No one is going to agree on how a specific magnet sounds – if a minor change in frequency resulting from a magnet change can alter our perception, then a big change in frequency from a coil change is going to alter it too, and you’ve got to take that into account. Combined with the fact that we’re dealing in perception? In opinion and taste? You’ve got more hope in settling the Gibson® vs. Fender® argument!
4. Whilst there are no “hard and fast” rules – treating some of the old wives tales with a bit of credibility, won’t see you go far wrong. Hotter pickups generally want to be more defined, so benefit from strong magnets, more traditional offerings generally benefit from a little added warmth, so weaker Alnico s are a safe bet – but please, go in knowing that its very much a matter of personal taste.
Orientation
Right then – officially speaking, magnets come in 2 forms – Isotropic (Unorientated) and Anisotropic (orientated) .
Now – a lot of nonsense has been written about the subject over the years – that you must use Anisotropic magnets to create a 1957 spec humbuckers, or an unorientated Alnico 5 for that “oh so sweet” 61 tone, and frankly – when you know a little bit about magnets, it doesn’t really make a great deal of sense!
Basically, an unorientated magnet is capable of being polarised across any of its axis (so, with a bar magnet, normally the 62 (or 58)x 3.2mm face is the pole – and when its fitted into a humbuckers, it will work – one face must be north, the other must be south, that charges your poles, which then means they’re opposite polarities, and combined with the reverse wiring on the coils… it just works. That’s how a humbuckers functions.
So, having the ability to charge a bar magnet so the 12.5x3.2 or the 62x12 face is the pole – is frankly, useless – it might be doable, but it wouldn’t be able to function properly in a pickup (at least, notwithstanding a few weird exceptions!) – so, take it from me – no matter if your bar magnet is orientated or unorientated – its orientated! It has to be polarised a certain way to actually work.
BUT – that’s all pretty academic too – because the grades of Alnico actually have “prebuilt” orientations (and no one seems to have spotted that when they’ve been speaking about orientation being this magical property in the quest for guitar tone ;-) ) – Alnico 2 and 3 are Isotropic, 4, 5 and 6 are Anisotropic – and that’s not up for debate! You can’t make an anisotropic Alnico 2.
The only exception, is Alnico 8 – you CAN get that in either/or! (but that’s a bit of an over simplification, an Alnico 8 capable of being orientated would be made of different quantities of its materials then one capable of being unorientated… it’s just both fall within the “ball park” of being Alnico 8) – but its bordering on the academic really – it’s a rarely used magnet at the best of times, and whichever way you cut it, it’s going to be polarised the same way. (if it keeps anyone awake at night, ours are unorientated)
So – why does it matter?
Well – theres some thinking that an “unorientated” magnet is weaker than an “orientated” one – and that’s going to magically make you sound “better”/”warmer”/”more vintage”… whatever intangible measure people like to justify this stuff!
And, its true!... but not for any reason to do with the magnets orientation - its purely down to the grade of the magnet, its inherent strength.
As we see on the bode plots for the magnets in the other tab, we can see that weaker magnets generally allow a pickup to produce more bass frequencies – so yes, if we assume an unorientated magnet IS weaker, then yes, it WILL produce more bass/sound warmer.
However – remember – an unorientated Alnico 5 cannot exist! Nor can an orientated Alnico 2! (only Alnico 8 can be a “fair” test) – so what people are actually saying when they argue the case for “orientated vs. unorientated” is actually “one grade of Alnico vs another”… and that’s about the long and short of it!
So yeah, honestly? Don’t fall for the hype – someone has just made up the idea that Gibson® used something at some point (in reality, Gibson® probably didn’t know what they were using!) and its snowballed into this mythic thing that doesn’t actually exist.
The only time it can, is Alnico 8s – and trust me, that isn’t coming up often enough to really worry about!
Furthermore – and this is purely hypothetical – the differences between the “sensible” Alnico grades in terms of tone, is pretty minimal. The idea that there is a magic “half way house” between 2 and 3 or 4 and 5 is a nice idea, but in real terms, even if it could exist due to something as simple as the isotropic nature of the magnet – your unlikely to be able to taste it – the difference between similar strength grades of magnet is so small, that trying to find a spot “in the gap” is just foolish.
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