The electric guitar has shaped popular music for nearly a century, with pickups playing a central role in its distinctive sound. These components transform string vibrations into electrical signals, acting as the instrument’s “heart.”
Guitarists have long known that the magnetic force from pickups affects sound quality, or timbre. However, Takuto Yudasaka, a visiting scholar at McGill University and Yamaha researcher, took things to the next level. The researcher devised a computer model that closely simulates the physics of the moment an electric guitar is strung.
“In electric guitars, the vibration of a magnetized string generates an electric current in the pickup coil,” said Yudasaka. “This current is very weak, but by winding the coil thousands of times, more signal can be detected.”
What makes a guitar pickup shine
Each pickup contains a magnet and a coil of wire. When the guitar strings, typically made of ferromagnetic material, vibrate above the magnet, they disturb its magnetic field. This disturbance induces a weak electric current in the coil of wire wrapped around the magnet. The signal generated then travels to an amplifier, which boosts it to create the rich, powerful sound associated with electric guitars.
Yudasaka confirmed previous knowledge and learned new things about the physics of pickups that could dramatically improve the guitar design process in the future. For instance, the coil winding process significantly impacts the sound. Increasing the number of windings boosts the output volume, but excessive winding can reduce clarity. Even slight adjustments in winding — down to a hundredth of a millimeter — can alter the sound discernibly to trained ears.
Several factors influence the guitar’s sound, including wire type and thickness, winding pattern, pickup shape and size, and magnet type.
Traditionally, pickup designers and engineers had mainly relied on their experience accrued over decades to balance out all these factors. What Yudasaka and his team aim is to add more science to this process and demystify the search for the perfect sound by reducing the guesswork.
“We were able to understand how the magnetic force of pickups affects the sound of electric guitars and how we can simulate it,” said Yudasaka. “This simulation has the potential to not only reduce design time but also to enable the development of electric guitars with new timbres.”
The findings were presented at the joint meeting of the Acoustical Society of America and the Canadian Acoustical Association. The conference runs from May 13-17 at the Shaw Centre in Ottawa, Ontario, Canada.
