For many people who lack electricity knowledge, these debates seem profound. Because the electrical principle of the pickup is easy to understand, this paper focuses on the relationship between the electrical characteristics of the pickup and sound. It’s a pity to tell you that the vast majority of manufacturers make more money by walking around misleading information in their product publicity and disrupt their competitors. So some conceptual revisions are necessary.
There are two basic types of pickup, electromagnetic pickup and piezoelectric pickup. The latter can cooperate with any type of string (metal string, nylon string). The electromagnetic pickup consists of magnets and coils and can only work with metal strings. Single-coil pickups are sensitive to magnetic field changes caused by transformers and fluorescent lamps, so it is very easy to pick up humming and noise from these sources. Two coil pickups or “humbucking” pickups use two specially matched coils to reduce interference. Because these coils have opposite phases, conventional signals (such as humming, which is transmitted to two coils at the same amplitude) tend to cancel each other out.
Different types of pickup have different ways of magnet placement. Some pickups insert cylindrical or bar magnets directly into the coil, while others place magnets under the coil and install soft cores in the coil. In most cases, these cores are screw-shaped, and the output amplitude of each string can be balanced by adjusting these screws. Some pickups have metal shells to cover and protect coils, others use plastic shells that do not resist electromagnetic interference, and others use only insulating tapes to protect coils.
The magnetic force line passes through the coil and a small string. When the string is stationary, the magnetic flux through the coil is a constant. When the string is stirred, the magnetic flux changes, which causes the voltage in the coil. Vibrating strings produce alternating voltages with their frequency of vibration. The amplitude of the voltage is proportional to the speed of the strings’movement (not the amplitude of the strings’ vibration). In addition, voltage is also related to chord thickness, permeability, magnetic field, and the distance between magnetic poles and strings.