Bass guitar in 1958. 1956 saw the appearance at the German trade fair "Musikmesse Frankfurt" of the distinctive Höfner 500/1 violin bass made using violin construction techniques by Walter Höfner, a second generation violin luthier. The instrument is often known as the "Beatle Bass", due to its endorsement and use by Beatles bassist Paul McCartney. In 1957 Rickenbacker introduced the model 4000 bass, the first bass to feature a neck-through-body design in which the neck is part of the body wood. The Fender and Gibson versions used bolt-on and glued-on necks. With the explosion of the popularity of rock music in the
Bass guitar ferrous metal strings within the magnetic field of the permanent magnets in magnetic pickups produce small variations in the magnetic flux threading the coils of the pickups. This in turn produces small electrical voltages in the coils. Many bass players connect the signal from the bass guitar's pickups to a bass amplifier and loudspeaker using a 1/4" patch cord. These low-level signals are then strengthened by the bass amp's preamplifier electronic circuits, and then amplified with the bass amp's power amplifier and played through one or more speaker(s) in a cabinet. Most basses have a volume potentiometer ("pot" or "knob"),