An acoustic bass is an instrument that looks like a western guitar. Its body is larger, however, and the instrument has the typical fourth tuning of an electric bass or double bass. The scale length is also longer than that of the guitar, as it usually corresponds to that of an electric bass (864 mm). Most acoustic basses have four strings, but there are also five and six-string instruments with fretless or fretless fingerboards. Since acoustic basses cannot really keep up with a western guitar or percussion instruments in terms of volume, these days the instruments usually have a preamplifier on board. Apart from the acoustic sound, the player has the option of amplifying the bass electrically in order to assert himself in the band.