Your bass guitar’s pickups convert string vibrations into electrical signals that can be amplified. They come in different shapes and sizes.
Magnetic pickups use magnets wrapped with copper wire to transform changes in magnetic field into audio signals, and you may also encounter humbuckers (two pickups in one unit) or piezo-electric pickups on acoustic-electric basses.
Adjustable Height
Fender Precision and Jaguar basses that utilize traditional magnetic pickups require their pickups to be set at the appropriate height in order for them to operate optimally. Setting them too high would limit their ability to detect string vibrations and convert them to electrical signals while setting them too low could result in thin or quiet tones.
Pickup height adjustment is relatively straightforward for bassists. Most can simply turn their humbuckers by twisting the mounting screws either side of the body to raise or lower them; most players recommend setting their pickups 2-3mm away from strings to hear tone without negatively affecting sustain.
For guitars with non-humbucking pickups like Strats and Mustangs, however, the process can still be achieved using small springs to push down on the bottoms of mounting screws. You can find such springs on the internet and many come equipped with adhesive backing for easier installation. Foam may work as an alternative but wear out over time or become stiff; spring foam comes equipped with its own integrated spring to maintain optimal pickup height.
As another way of adjusting pickups, spacers that sit between the body and pickup can also help adjust them – you can find these online or in most bass stores. They are especially beneficial when working with pre-CBS guitars without mounting screws or those featuring piezo-electric pickups.
Piezo-electric pickups may not be found on many bass guitars, but they’re an intriguing innovation that uses light to convert string vibrations to an electrical signal. Installed under the bridge for discreet operation while providing optimal output.
No matter which bass you play, the key to finding your ideal tone lies in experimenting with various setups and listening carefully to how your instrument sounds. A bit of trial-and-error can go a long way towards discovering it; an incorrect pickup height could wreak havoc with its tone; with patience however, setting up pickups that give off maximum sound is possible.
Noise Reduction
Under most body-mount bass pickups sits a piece of foam designed to assist in setting their height and angle as they’re screwed into place. Over time, though, this foam may compress over time and stop pushing back against them, leading to lost height adjustments or worse still, one end of a pickup rising without raising both ends – the solution: replace the foam.
Real rubber — such as that sold as weather stripping — is ideal for this task, while household sponges should be avoided as these tend to decompress easily under pickups. Polyethylene foam packaging material compresses harder than its rubber counterpart, but still works great under a pickup. You can purchase this online or from hardware stores, with lasting performance.
Springs offer another economical and long-lasting alternative to foam. However, their vibration can create microphonics noise. You can solve this by either pressing polyethylene foam against them directly, or cutting a square and punching four holes through it before forcing springs through it – either way this dampens vibration and eliminates noise altogether.
Piezo-electric pickups are another intriguing innovation found on guitars and basses alike, usually installed beneath the bridge. While magnetic pickups rely on magnetism to convert string vibrations to sound waves, piezos instead use physical pressure changes caused by string vibrations to generate an electrical signal. They’re commonly found on acoustic-electric guitars but can also be found on basses.
A third option is the Super Natural Plus pickup system, constructed of plastic cover designed to resemble dark-grained rosewood. Easily installing beneath strings, this pickup is suitable for dreadnought-sized basses and features shock-absorbing foam lining its mounting brackets to help prevent it from rubbing against sides of soundhole.
Isolation
Adjusting or changing a pickup height adjustment on a bass guitar can drastically alter its sound. This is due to how its magnet floats above the strings, where it can be affected by vibrations from nearby lightbulbs or amplifiers and cause buzzing or feedback that disrupts performance. An easy solution could be adding insulation such as foam under the pickup that acts as an insulator to help dampen vibrations and block out interference sources from other sources of interference with its performance.
Foam is an economical solution to this mod, as it can be purchased cheaply and effectively. Furthermore, spring foam will last much longer than springs do – eliminating microphonic noise generated from these springs themselves and their microphonic microphonic noise that often results in bass guitar noise issues.
Foam can also help compensate for different string gauges by adjusting pickup height on bass guitars. Heavier bass strings may disrupt magnetic fields more than lighter treble strings and cause thin sounding guitars; using foam pieces to lower pickup height to accommodate for heavier bass strings can eliminate this issue and give bass guitars fuller tones.
This same concept can also be applied to correcting the polarity orientation of humbuckers. Depending on which magnet type is being used, changing its polarity orientation can drastically change both tone and sound according to volume/tone controls – for instance if bass sounding harsh, switching to weaker magnet like Alnico 2 may soften up its sound more.
Bassists who need an easier and more effective solution may use pieces of foam cut to fit underneath the base plate of their direct mount humbucker or body-mount bass guitar pickup, featuring springs to ensure constant force on its coils. Once assembled, these foam pieces can simply be adhered directly onto their respective pickup’s base plates with small dots of adhesive glue.
Durability
Underneath most body-mount bass pickups lies a dense piece of foam. This material pushes against mounting screws as they tighten them down for height adjustments, helping prevent the pickups from loosening during play and coming loose altogether.
Foam can wear out over time or become compressed so much that it no longer performs its task, rendering its height adjustment obsolete and leading to excessive bass resonance, potentially altering tone quality in an undesirable way.
Replace foam with something more durable – medical tubing from most drugstores or fuel hose used with nitro RC cars could both work, both being inexpensive, durable materials. Medical tubing holds its shape well while never vibrating; fuel hose is easily cut to size for installation purposes as well.
Some people utilize a similar method by wrapping bicycle tire rubber around a thick piece of rubber, however this can become worn-out or compressed to such an extent that its height adjustment loses effectiveness or even causes it to slip off completely.
Other pickup-mounting methods use springs or wood shims as support, but these can become worn down over time or too stiff. Spring foam provides an effective alternative that has its own internal spring system which keeps your pickup at its desired height without needing manual adjustment – plus, its cutting feature makes cutting to size simple! It comes in sizes for both P and narrow soapbar style pickups!
There are other pickup-mounting solutions that may help with this problem, including an internal screw that allows you to adjust middle string pole height independently from both ends of the bass body. Unfortunately, however, removing the pickup may be impractical in vintage instruments or for players without extensive knowledge in working on bass guitars.
Many bassists mistakenly assume their sound comes from their strings, when in reality it comes from transducers, which convert signals between forms of energy. Early electric bass (and guitar) pickups were simple magnetic windings which converted string vibrations into electrical signals amplified through amplifiers; modern electric bass pickups come in many varieties ranging from single coil pickups through split coil and double coil (humbucker) pickups that cancel electromagnetic interference such as hum or buzzing noises.