The bass guitar is a stringed instrument similar in appearance and construction to an electric guitar, except with a longer neck and scale length, and four to six strings or courses. The four-string bass 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. The bass guitar is a transposing instrument, as it is notated in bass clef an octave higher than it sounds. It is played primarily with the fingers or thumb, by plucking, slapping, popping, strumming, tapping, thumping, or picking with a plectrum, often known as a pick. The electric bass guitar has pickups and must be connected to an amplifier and speaker, to be loud enough to compete with other instruments.