Many basses carry more than one pickup (rarely more than two) placed at different positions. Precision basses are almost unanimous in placing one split-coil pickup at the center, while jazz or hybrid basses have two different pickups placed at the top (near the neck) and bottom (reaching the bridge). With that said, many people might be wondering if there is any substantial difference in sound between a neck pickup and a bridge pickup.
What are the differences between neck and bridge pickups of bass guitars? Bass bridge pickups generally have a thinner/brighter sound since they're closer to the strings' anchor point. Bass neck pickups sound fuller/darker, as the strings are able to produce a wider vibrating motion around that area and, thus, the fundamental and lower harmonics are better represented.
In this article, we'll elaborate on the differences in sound (vibration and pickup placement) and explore the various types of pickup configurations commonly found in basses, particularly the J-style, P-style, and P/J-style pickups.
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Why Do Bridge Pickups & Neck Pickups Sound Different?
As asserted earlier, the positioning of the pickup affects the sound, rendering more treble-heavy notes near the bridge and “bassier” notes as it approaches the neck/fretboard.
The differences aren't due to the differences in pickup design (though some pickup sets have different specs for the bridge and neck pickup). Rather, the differences boil down to how the strings vibrate at/above the pickup location and the way the pickup handles those vibrations.
When strings are plucked, strum, or picked, they are set in an oscillating motion called vibration. A string's vibration is described as a “wave” and is measured by various indicators. For sound production, the vibrational frequency and the length of the vibrating object are the most important factors.
All else being the same, the shorter the length of the string, the higher the frequency will be. This is because the string's mass will not be able to move as great a distance and, therefore, it will take less time to get from one point to the other during the motion.
The fundamental frequency (also known as the first harmonic) of a string is the oscillation that happens with the nodes at the two ends of the string (typically the bridge and the nut or fret) and the antinode at the centre of the string between the two nodes.
However, there are higher harmonics that vibrate as well. A vibrating string will have many harmonics, often with amplitudes inversely correlated to their number. Let's consider the fundamental and the first few harmonics with nodes and anodes:
- Fundamental or first harmonic (frequency = f):
- 2 nodes (one at each end)
- 1 antinode (in the middle)
- Second harmonic (frequency = 2f):
- 3 nodes (at one end, the centre, and the other end)
- 2 antinodes (at the 1/4 and 3/4 points)
- Third harmonic (frequency = 3f):
- 4 nodes (at one end, 1/3, 2/3 and the other end)
- 3 antinodes (at 1/6, the centre, and 5/6)
- Fourth harmonic (frequency = 4f):
- 5 nodes (at one end, 1/4, the centre, 3/4, and the other end)
- 4 nodes (at 1/8, 3/8, 5/8 and 7/8)
Here's an image to represent the first four harmonics of a string. The maximum displacements are defined as the black solid and dotted lines; the nodes are marked with green dots, and the antinodes are marked with red dots. Envision the righthand black box as the bridge and the lefthand black box as the nut (open string) or fret (fretted string).
As the strings are freer to move around the area between the neck and body, the fundamental vibration frequency will be well represented, and the string's harmonic profile will be fuller. This will result in a fuller tone. Note that home higher harmonics may have their nodes above the neck pickup, though these harmonics typically aren't strong, to begin with.
As we reach the anchor points of the strings (in this case, the bridge), they will turn stiffer and more restricted. This affects all the harmonics but has a particular effect on the fundamental and first few harmonics, which naturally have the strongest vibrations away from the anchor points. Therefore, the tone will be thinner due to the relative lack of fundamental and low harmonics.
The hand's position with regard to the string is just as relevant as the placement of the pickup. You may try plucking the strings at different distances from the bridge to notice that variation. This is because the string, when played at the more rigid points, will be met with more resistance because of the tension caused around that area, so the force applied by the playing hand will not be enough to produce wider oscillations.
Now that we've established how the strings produce their sound and the difference in harmonic composition (tone) between different positions, let's delve into another component responsible for the sound delivery: the pickup.
Pickups are common to all solid-bodied guitars, that is, to guitars and basses devoid of the hollow soundboxes present in traditional acoustic or classical/Spanish guitars.
A pickup is composed of a set of magnetic bars made from ceramic, alnico, or neodymium that are wound by conductive enamelled wire. The wiring system that rests under the bobbin, embedded by a row of magnets, is called a coil. Pickups may consist of either one or two coils (the latter is classically called a “humbucker pickup”).
The magnetic pickup magnetizes the strings. When strings vibrate, they create a changing magnetic field. The conductive coil then transforms this changing magnetic field into electric signals via electromagnetic induction. The fundamental frequency and harmonics of the vibrating string(s) are effectively converted into coinciding audio signals.
These pickups are placed below the strings and transduce the vibrations generated in their vicinity, effectively acting as “antennas”. They operate similarly to a dynamic microphone, with the difference being the input mechanism.
Since a string's vibrational characteristics change along its length, the position of the pickup will ultimately affect the sound when we consider the above explanation. Naturally, if you place the pickup at a spot where the strings are more constricted and produce weaker low harmonic vibrations, the higher frequencies will be relatively pronounced. Conversely, if you place it closer to the middle of the string, the lower harmonics will be stronger.
Furthermore, the design of the neck and bridge pickups of a bass guitar may be different, which we'll discuss in the upcoming section on Precision/Jazz “P/J” hybrid bass guitars.
P-style, J-style & P/J-style Pickups
Electric basses can be classified as Precision, Jazz, and Hybrid (or P/J). Depending on the type, they will sport a different pickup configuration. J-style and P/J-style pickups are very relevant to this subject since they sport both neck and bridge pickups, while P-style is only worth a brief mention.
It should be pointed out that no two basses sound exactly the same. The type of pickups installed is just as important as their distribution.
For example, you'll be able to find that some basses come endowed with active pickups and passive pickups (or a combination of the two). Other basses have railed pickups (which function by way of magnetic rails instead of poles) or optical pickups (which use light sensors instead of magnets).
Piezoelectric pickups are mostly employed in acoustic basses or as an add-on to electric basses, though these piezo crystal pickups aren't generally positioned at the neck or bridge.
Precision basses come traditionally equipped with a split-coil pickup in the middle, also called a P-style pickup (the “P” stands for “precision”). Split-coil pickups are humbuckers that are split and bound by half.
Note that a P-style pickup, as pictured below, is a single pickup split into two halves. There's no “neck” and “bridge” pickup here.
These pickups are traditionally set up so that the top coil is placed under the lower notes while the bottom coil is set under the higher notes.
This is meant to create a tonal balance by which trebles and basses are both equally emphasized. Though the difference is subtle, the top coil's closer proximity to the neck helps increase bass response, while the bottom coil's closer proximity to the bridge helps increase treble response.
Naturally, since the coils are not totally parallel to each other, there will be slight interference.
In general, these basses tend to have a “fatter”, rounder sound with prominent sustain. This makes them great for rock and pop music.
Jazz basses have two slim single-coil pickups called J-style pickups: one connected at the bottom near the bridge and the other connected closer to the neck. Each coil normally has one small magnet pair for each string to soften the attack.
Typical J-Bass wiring has the neck and bridge pickup wired in parallel, each with its own independent volume control, along with a master tone control. Turn up the neck pickup for a fuller, deeper sound. Turn up the bridge pickup for more attack and treble.
Also, as you play or pluck the strings near the bridge pickup, you will get a trebled tone, while playing the strings near the neck will produce a warmer output.
The general sound of these basses is “punchier” and more defined, owing to the single-coil setup, which stresses the high-frequencies. This allows for more breathing room for other instruments and clearer solos, which is crucial in a jazz setting.
P/J Hybrid Basses
P/J basses are some of the most versatile basses available. They are assembled by mixing the body of a “P” bass and the neck of a “J” bass. The pickups are also combined with a J-style neck pickup (or another type of humbucker pickup in its place) and a P-style bridge pickup.
It was first introduced by Ibanez in the 1970s, and it was meant to offer the best of both worlds. These basses are very popular among session bassists and those who perform in a great variety of genres and styles since they'll be able to carry a one-size-fits-all instrument. They don't need to purchase and/or carry two different basses.
Typical P/J-Bass wiring has the neck and bridge pickup wired in parallel, each with its own independent volume control, along with a master tone control. Turn up the neck pickup for a fuller, deeper sound. Turn up the bridge pickup for more attack and treble.
Modern P/J basses come with a variety of enhanced wiring configurations. Some have switches that enable you to shift between the bridge single-coil pickup, the neck dual-coil pickup, and a blended effort of the two (for those who prefer a more mid-range response). Others have active EQ or simple blend controls instead of independent volume controls.
To learn more about pickup switches, check out my article How Do Guitar Pickup Switches Work & How To Use Them.