Lots of custom guitars these days have custom magnetic pickups, and as a fellow guitar player, it always intrigues me how something as simple a concept as a magnetic pickup can contribute to sounds so complex and fantastic.
You’ve heard of pups numerous times, but do you know how they work?
Magnetic pickups are – as the name suggests, just a magnet with a coil wrapped around it. The coil is conductive, meaning that it allows electricity to flow through it – and we will get into how it works in a bit, but the coil is then hooked up to the knobs on the guitar body so the player can customize their sound in ways they can imagine.
There are many terminologies related to coil, magnets, and the wiring configurations, but we’ll start slow and easy. The copper wire wrapped around the magnet also contains some insulation so there won’t be any internal shorts, and the coil connects to the guitar jack. The idea is to pass a signal (generated after vibration of strings) through the guitar’s jack so it can be amplified with the help of a guitar amp.
The magnet can come in various shapes and sizes, but the most common ones today are rectangular magnets that are mounted just below the coil. When the strings vibrate, the magnetic field within the conductive coil changes – this leads to signal generation in the coil (a process called Faraday’s electromagnetic induction).
I’ll leave mathematical derivations to physicists who understand them much better than them, but the gist is – as long as there’s a good coil and a change in the magnetic field by string vibrations, current will always be produced in the coil, no matter how small. The problem is – the small current is too small to be heard if we pass it directly to the speaker, so we take that signal, chop off the highs, boost the lows, and increase the signal intensity (amplification) so it’s powerful enough to be heard through a speaker – sometimes too loud!
So, in a nutshell – the pickup is converting string vibrations (mechanical energy) to signals that ultimately drive the speaker so we can hear them loud and clear.