As most musicians already know, Fender-style guitars are often equipped with single-coil pickups, and Gibson-style guitars are more often found sporting dual-coil “humbuckers.”
By reversing the polarity of one magnet, the hum-bucking design reduces 60 cycle noise through phase cancellation. But it also has a dramatic impact on tone. Since the two magnets of a humbucker are wired “in series”, with the output of one magnet adding to the output of the other, humbuckers have far hotter output. But all things being equal, they’ll also have a significantly darker tone than a comparable single-coil. (It turns out that the clever phase cancellation trick of these pickups doesn’t just “buck” the hum, but also the highest frequencies.)
Single coils (which sound bright, glistening and bell-like in comparison to the smooth, crunchy or creamy response of the humbucker) are traditionally susceptible to plenty of noise when they’re played in isolation. But modern guitars offer some workarounds here: First, the “in-between” positions on a Stratocaster or Telecaster make use of 2 pickups. Since one magnet will be reverse polarity, this means that they have the same hum-rejecting benefit of a true humbucker. But, since they’re far apart and wired in parallel, splitting the output volume between the two pickups, they retain that single coil “quack” and “chime” while reducing noise. Some modern guitars come with hum-cancelling “stacked” single coils that operate on a similar premise.
Pickup positioning is also a big deal, as most guitarists already know. Part of what makes a telecaster bridge pickup sound so twangy is its placement – not just its design. Often enough, just switching pickups or strumming-hand position on a guitar is a far better call than swapping instruments or debating the finer points of pickup construction. But with that said, different pickup designs and materials can often significantly different tones.
In general, more “vintage” sounding guitars will have weaker magnets, while more modern-sounding instruments will have more powerful magnets. There’s a lot a designer can do with coil winding and magnetic field calibration to alter the tone of a pickup, but the raw materials are key as well.
Most classic pickups are made out of “Alnico,” a blend of aluminum, nickel and cobalt. (See what they did there?)
Alnico “2” is the weakest of these metal magnets, and very common in vintage-style designs. It offers a sweet, supple tone with a slightly compressed dynamic response that a lot of guitar players love. The next most common alloy is Alnico “5”, which is higher output and is often used in hotter, more modern designs.
On the far end of the spectrum, you have Ceramic Magnets which offer super-high output and a far brighter tone. These are most often used in humbucker designs, particularly when players want even more gain or a bit more articulation to combat the darkening effects of a humbucking design.
There’s more than enough to the world of guitar pickups to warrant a whole series of articles covering active vs. passive, series vs. parallel, over-winding vs. under-winding, and the special appeal of P-90 and “lipstick” pickups. But for now, you’re welcome to check out the websites of pickup manufacturers like Seymour Duncan and DiMarzio to read more and to hear some of these differences for yourself.
Accessories: More Impact Than You Might Think
So far, we’ve covered the body, head and voicebox of the guitar, and that’s what matters most aside from the person playing the thing. But there’s one more thing to mention: Engineers are often surprised to find that minute changes in guitar accessories can help make for a significant impact on tone.
Any engineer knows that when it comes to mic cables, balanced line cables, speaker cables and power cords, the impedances are too low and the voltages too high for high-end voodoo cables to make much of an appreciable difference in sound quality at all, particularly on normal-length runs. In the guitar world however, things are a little different. Thanks to the low voltage and high impedance of passive guitar pickups, slight variations in the capacitance or inductance of a cable can actually make a subtle difference, that can be measured, and in some cases, heard blind. This is not to say that all guitar cables will sound different from each other – but some can.
But far more important than this are some of the physical changes that go in the world of accessories: Changing your saddles or adding mass to the bridge? Yes, it actually can effect tone and sustain. Switching to new tuners or a low-friction nut? Yes, you can improve tuning stability. Switching picks or strumming position? Hells yes. In fact, understanding how these physical performance choices effect tone is perhaps more important than anything we’ve covered so far. Don’t just get to know your guitars. Get to know your guitar picks.
If you know how music is really made, then you know that in the end “the tone is in the fingers.” But that doesn’t mean nerding out about the tools now and then isn’t fun and worthwhile. If getting interested in these variables, even right up to the point of diminishing returns, keeps us interested and engaged then it’s well worth the effort. It’s only when you let an interest in tools supercede your interest in music that you’re really in trouble.
If you’re enough of a guitar nerd to have swallowed this article whole, then know this is just an introduction to a whole field of knowledge. Click on to read more about DIY setups, intonation and action adjustments. And if you ever find yourself getting too obsessed, remember that the perfect guitar is the one that you’re playing – regularly and well.
Justin Colletti is a Brooklyn-based audio engineer, college professor, and journalist. He records and mixes all over NYC, masters at JLM, teaches at CUNY, is a regular contributor to SonicScoop, and edits the music blog Trust Me, I’m A Scientist.