<sod>Most electric bass guitars use magnetic pickups. The vibrations of the instrument's ferrous metal strings within the magnetic field of the permanent magnets in magnetic [[pick up (music technology)|pickups]] produce small variations in the magnetic flux threading the coils of the pickups. This in turn produces small electrical voltages in the coils. These low-level signals are then [[Bass amplifier|amplified and played through a speaker]]. Most basses have a volume [[potentiometer]] and a tone potentiometer, which rolls off the high frequencies. Some basses may also have a pickup selector control or switch. Since the 1980s, basses are often available with battery-powered "active" electronics that boost the signal with a [[preamplifier]], provide [[equalization]] controls to boost or cut bass and treble frequencies, or both.<eod>
<sod>Most electric bass guitars use magnetic pickups. The vibrations of the instrument's ferrous metal strings within the magnetic field of the permanent magnets in magnetic [[pick up (music technology)|pickups]] produce small variations in the magnetic flux threading the coils of the pickups. This in turn produces small electrical voltages in the coils. These low-level signals are then [[Bass amplifier|amplified and played through a speaker]]. Most basses have a volume [[potentiometer]], which can be turned up or down, and a tone potentiometer, which rolls off the high frequencies when it is turned to the player's right. Some basses may also have a pickup selector control or switch. Since the 1980s, basses are often available with battery-powered "active" electronics that boost the signal with a [[preamplifier]], provide [[equalization]] controls to boost or cut bass and treble frequencies, or both.<eod>