Like the traditional electric bass and the double bass, the acoustic bass guitar commonly has four strings, which are normally tuned E-A-D-G, an octave below the lowest four strings of the 6-string
guitar. Like the electric bass guitar, models with five or more strings have been produced, although these are less common. In part, this is because the body of an acoustic bass guitar is too small to produce a
resonance of acceptable volume at lower pitches on the low "B" string. One solution uses the five string acoustic bass to add an additional high string ("E-A-D-G-C") instead of adding a low "B". Another solution is to rely on amplification to reproduce the low "B" string's notes, or by making the body a little bit larger. AB-10
acoustic-electric bass guitar There are also
semi-acoustic models, fitted with pickups, for use with an amplifier. The soundbox of these instruments is not large enough to amplify the sound. Instead, it produces a distinctive tone when amplified, similarly to semi-acoustic electric guitars. Thin-body semi-acoustic basses such as the violin-shaped
Höfner made famous by the early
Beatles and several
Fender models are not normally regarded as acoustic basses at all, but rather as hollow-bodied bass guitars. There are also semi-acoustic basses such as
Godin Guitars' "A-Series" that, once amplified, sound much closer between acoustic bass guitars and
upright basses (double bass), and have been used in professional circles to "simulate" one when it would be impractical for transportation and other reasons to use a full-sized upright bass. As with semi-acoustic electric guitars, the line between acoustic instruments fitted with pickups and electric instruments with tone-enhancing bodies is sometimes hard to draw. Some instruments can also be equipped with a variety of pickups such as
piezo pickups, the "standard" of acoustic-electric instruments as well as
synth pickups that can replay "virtual" upright bass sounds and bring a semi-acoustic bass much closer to a double bass sonically.
Saga Musical Instruments produces a four-string bass
resonator guitar under their
Regal brand name.videos
National Reso-Phonic Guitars also produce three models of resonator bass guitar. One notable player of the resonator bass guitar is
Les Claypool of
Primus, who plays Regal RD-05 resonator basses. ==Manufacturers==