The guitar pickup is the medium converting vibrations of guitar strings into electrical signals. After being boosted by the amplifier, these signals are output to the speakers and become sound. If you take the pickup apart, it is a device mainly composed of magnets and metal coils and other components like housing, magnetic pole adjustment screw, etc…In this case, magnetic force and material of the magnets are the key factors that determine the tone. On the other side, the number of turns of the coil also has a great influence on the sound.
Ceramic magnets were first used in pickups. With the invention of Alnico magnets, Alnico magnets became the most popular magnets for pickups.
The family of Alnico pickups
The Alnico III：
the warm intermediate frequency and slightly prominent high frequency make it a good pickup for middle frequency.
The Alnico II:
the low frequency of Alnico II comes out compared with Alnico III. With a relatively moderate magnetism, it could be defined as a balanced pickup, but still, it is a good pickup for middle frequency.
The Alnico V:
The Alnico V is widely owned by music and guitar lovers. The high magnetism makes it very sensitive to the subtle vibrations of the strings, it shows a powerful, bright tone. The Alnico V maximizes the characteristics of the instrument itself to provide a perfect performance.
Ceramic Magnet Guitar Pickups
Ceramic pickups offer a very strong tone at high frequency. With clear, focused high and low ends, these are the preferred pickups for metal players since they provide plenty of output and punch.