How do Guitar Pickups Work?

By Mark
Published on

We’ve explored how an acoustic guitar works, how an amplifier works, and even how guitar pedals work.  Today we’re going to explore an important part of how electric guitars work.  I’ve done a great deal of research on the subject of pickups, and today I’m going to share my findings.  Here are the things we’re going to cover in this article:

What is a Guitar Pickup?

How does a Guitar Pickup Work?

Two main types of Guitar Pickups

What does higher output mean?

Why Do Identical Pickups Sound Completely Different?

 

What is a Guitar Pickup?

single coil pickup

A pickup is a transducer, a device that takes one form of energy and transforms it into another.  In the case of the electric guitar, the movement of the strings creates a disturbance in the pickup’s electromagnetic field. The changes in the magnetic field turn into an electrical signal. 

The pickup is the most important part of a guitar that contributes to its tone.  For example, you can have a guitar with stock pickups that sounds mediocre.  Change the pickups in that guitar with a set of Seymore Duncans or EMGs and that guitar is going to sound hot.  

In its simplest form, a guitar pickup is a magnet with a copper wire wound around it.  This is the main difference between the acoustic guitar and the electric guitar.  An acoustic guitar creates its sound purely on vibration.  The plucked strings move back and forth, transferring energy into the top soundboard of the guitar. This transfers energy into the air molecules surrounding it to create a soundwave that reaches your ears.  This differs from electric guitars which depend on their pickups.  But how do pickups work?

How does a Guitar Pickup Work?

To understand how a pickup works, we need to understand the concept of electromagnetic induction.  Electromagnetic induction is the generation of an electrical current by creating a change in the magnetic field of the pickup.  

The pickup is placed on the guitar and laid underneath the strings.  The coil wound around the magnet creates an electromagnetic field around the pickups.  As a result, the strings become magnetized.  Strumming the strings creates a disturbance in the magnetic field and this creates an electrical signal that becomes amplified while passing through an amplifier.  

How does the magnet shape a pickup’s sound?

The magnet is the biggest contributing factor in determining the guitar’s tone.  There are three different types of magnets:

  • Alnico: these alloys are made of aluminum, nickel and cobalt.  The alloys are ferromagnetic, which means they can be magnetized and permanently hold magnetism
  • Ceramic: Less expensive magnets than alnico alloys.  They are also much stronger magnets, resulting in hotter pickups.  These magnets are well suited for hard rock, and metal styles of music.
  • Neodymium: These magnets are much stronger than ceramic.  And these are able to capture the pure sound of the instrument.  

How does the coil affect the pickup’s sound?

The coil greatly affects the sound of your pickup and the guitar. The coil is a long strand of copper-wound thousands of times around the bobbin or coil form.  The higher the number of wounds the greater the output.  However, if wound too much would create a pickup with weak treble.  Nowadays pickups are made with a precise number of wounds compared to the vintage days of hand-wound pickups.  In addition, the thickness of the coil and its insulation material also affect the sound of the pickup.  

Two main types of Guitar Pickups

There are two main types of guitar pickups: single coil and humbucking pickups or humbuckers.  Single coils are made of six magnetic pole pieces, a coil, and an output wire.  These pickups are known for their bright tone.  They are also known for their ability to pick up interference and other string noises as well.

Humbuckers are designed to provide greater output and noise rejection.  The first coil is a regular single-coil pickup but the second coil has inverted pole pieces with the magnetic south poles facing upward.  The coils are wired in series but out of phase.  By building the pickup this way, it cancels out noise interference and strengthens the magnetic field.  

humbuckers

One type of pickup isn’t better than the other.  It often depends on the type of sound you are trying to create.  Guitars can have a combination of the two pickups or only one type if that is preferred.  A very common type of pickup combination is to have two single coils and one humbucker pickup.  The pickup selector will be able to mix and match different combinations of all the pickups.  

How to Choose the Right Pickup

It always depends on what you are looking for as a guitarist.  Single coil pickups sound brighter and crisper compared to humbucking pickups.  Any humbucker will sound thicker and heavier.  But it also depends on how your guitar is routed.  Sometimes by the way that your guitar is routed, you may only be able to use a certain type of pickup on your guitar.

What about acoustic pickups?

There are a few options for acoustic guitars.  There are pickups that use electromagnetic induction similar to electric guitar pickups.  These pickups lie overtop of the soundhole underneath the strings.  There are also piezoelectric pickups that work off of vibrations rather than electromagnetic induction.  Magnetic pickups offer a warm sound while the piezo pickups sound bright and percussive.  There is also a combination of the two pickups called the MagMic, which uses both magnetic and vibration pickups.  

What does higher output mean?

Higher output means that the pickup will send a stronger signal through the amplifier.  You will be able to understand the difference if you have a moderate output guitar that sounds the same no matter how you play.  If you replace the pickups on that guitar with ones with higher output.  The result is a hotter signal and the sound becoming more distorted/overdriven because of the higher output.  But you can get cleaner sounds if you use an amp that doesn’t distort at higher outputs.

Is Higher Output Better than Moderate Output?

It will always depend on the player and the type of music that you play.  In some cases, higher output pickups can be too much of a good thing.  Higher output leads to much darker, more distorted tones.  However, if you feel like your guitar sounds weak, then you can remedy the problem by switching out the pickups for hotter ones.  

Passive Pickups vs. Active Pickups

active pickups vs. passive pickups

Passive pickups are the most common type of pickup.  These single coils or humbucking pickups transfer the sound of the strings to the signal chain without any additional power.  Active pickings contain a battery-powered pre-amp to boost the signal.  These pickups are the highest output pickups available.  Rock and metal guitarists love the sound of these pickups.  Jazz guitarists love them for their ability to capture a noise-free signal.  

Why Do Identical Pickups Sound Completely Different?

Each pickup hears vibrations differently depending on where it is placed on the guitar.  The pickup nearest the bridge will always sound different from the pickup closest to the neck.  The bridge pickup will sound much brighter.  This also depends on 

What next?

Now it’s your turn.  We’ve covered a great deal about what pickups do and how they work.  We’ve also covered a bit about active vs. passive pickups and output levels.  Are you using active pickups on your guitar? Is it time for you to switch and turn your guitar into a different beast?  It’s up to you to decide!

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