The bass guitar is similar in appearance and construction to an electric guitar, but with a longer neck and scale length, and four to six strings or courses. The four-string bass, by far the most common, is usually tuned the same as the double bass, which corresponds to pitches one octave lower than the four lowest pitched strings of a guitar (E, A, D, and G). The bass guitar is a transposing instrument, as it is notated in bass clef an octave higher than it sounds. The electric bass guitar has pickups and needs to be connected to an amplifier and speaker, to make a sound loud enough to compete with other instruments.
Since the 1960s, the bass guitar has largely replaced the double bass in popular music as the bass instrument in the rhythm section. While types of basslines vary widely from one style of music to another, the bassist usually plays a similar role: anchoring the harmonic framework and establishing the beat. Many styles of music include the bass guitar, including rock, heavy metal, pop, punk rock, country, reggae, gospel, blues, symphonic rock, and jazz. It is often a solo instrument in jazz, jazz fusion, Latin, funk, progressive rock and other rock and metal styles.
In the 1930s, musician and inventor Paul Tutmarc from Seattle, Washington, who was manufacturing lap steel guitars, developed the first electric string bass in its modern form, a fretted instrument designed to be played horizontally. The 1935 sales catalog for Tutmarc's electronic musical instrument company, Audiovox, featured his "Model 736 Bass Fiddle", a four-stringed, solid-bodied, fretted electric bass instrument with a 30 1⁄2-inch (775-millimetre) scale length. The adoption of a guitar's body shape made the instrument easier to hold and transport than any of the existing stringed bass instruments. The addition of frets enabled bassists to play in tune more easily than on fretless acoustic or electric upright basses. Around 100 of these instruments were made during this period.
Around 1947, Tutmarc's son, Bud, began marketing a similar bass under the Serenader brand name, prominently advertised in the nationally distributed L. D. Heater Music Company wholesale jobber catalogue of 1948. However, the Tutmarc family inventions did not achieve market success.
In the 1950s, Leo Fender, with the help of his employee George Fullerton, developed the first mass-produced electric bass guitar. Fender was the founder of Fender Electric Instrument Manufacturing Company, which made popular brands of electric guitars, basses and amplifiers. Fender's Fender Precision Bass, which began production in October 1951, became a widely copied industry standard for the instrument. The Precision Bass (or "P-bass") evolved from a simple, un-contoured "slab" body design and a single coil pickup similar to that of a Telecaster, to a contoured body design with beveled edges for comfort and a split single coil pickup.