Guitar and bass electromagnetic pickups are made specifically for those instruments. In the case of single coil pickups, they are made of multiple magnetic pole pieces aligned with the strings, around which coated copper wire is wound. The coil picks up the electromagnetic waves created by the vibration of the steel strings, which is then transduced into electrical current. That variable current is transformed into sound by a loudspeaker or an amplifier.
As I intend to create sound sculptures with the material with which guitars are made, I want to be able to use steel strings as single entities, rather than as an array. A string, its pickup, its bridges, and its tuning key would then be a single building block which would allow me to create a sound structure in whichever shape or form. From that point, I chose to create a pickup for a single string.
This component is named a "brutalist pickup". The research-creation I was conducting at the Topological Media Lab was also a means for me to explore Brutalism, which people thought was an influence for the sculpture in a previous work of mine, The Office of Dr. S. Plant. During the redesigns of the pickups, I went with hard corners, to honor the form of brutalist artworks.
Acrylic, alnico magnet, copper wire
Design and fabrication process
The original design was simply expanding the size of the magnetic pole piece enough to cover the thickness of the copper wire wound around the pole, and for screws to hold the bottom and top flatwork. From that point, the design went through different iterations as prototyping uncovered flaws or potential improvements.
The copper wire ends must be connected to regular wire, which is much more thick and resistant to manipulation. The way to ensure the connection between those two wire types is to use an eyelet as a medium. The eyelet is longer than the 2mm-thick plexiglass from which the flatwork is cut, which lead to the addition of a layer below the bottom one.
Afterwards, there was the matter of gluing the eyelet itself into the plexiglass. The setting tool usually used for the creating of real guitar pickups was to violent for the not-too flexible plexiglass, as seen in the image above on the left. When using Epoxy, the plexiglass broke because it expands as it dried. The solution was to use an acid-free water based quick dry adhesive.
As soon as the first prototype was completed—seen above—an issue became apparent: spooling copper wire around the magnetic pole piece would not work properly, as the head of the screws would be in the way of the bottom-most part of the magnet. That meant another redesign, one in which the screws that allow to attach the pickup to a body would not be in the way when spooling wire.
That's when I chose the more angled design, which felt appropriate.
At that point, spooling the coil became possible.
Using a freshly wound coil works properly, however not as an electromagnetic pickup. The air between the wire coils would allow the wire to be vibrated by sound waves. This effect is called a "microphonic pickup". In order to prevent that, and to ensure that electromagnetism is what is sensed, the air gaps between the wire coils must be filled.
The best way to do that is to dip the pickups in a mix of beeswax and paraffin. This process is called "potting the pickups".
Once all this is done, the only task remaining was to connect the coil ends with wire.
Many people provided technical assistance during the production of this prototype. I would like to thank the following people: