more easily heard on early sound recordings, as the recording equipment of that time did not capture low frequencies well. For more about the slap style, see "Playing styles," below. Double bass players who have contributed to the evolution of jazz include the Swing era player Jimmy Blanton, who played with Duke Ellington, and Oscar Pettiford, who pioneered the instrument's soloistic use in Bebop. The "cool" style of jazz was influenced by players such as Scott LaFaro and Percy Heath, whose solos were very melodic. Free jazz was influenced by the composer/bassist Charles Mingus (who also contributed to hard bop) and Charlie Haden, best known for his work with Ornette Coleman. In the 1950s, some big band bandleaders began to ask their upright players to use the then-newly available Fender bass, the first widely available electric bass. In the 1970s, as jazz and rock music were blended by performers to create the "fusion" genre, players such as Jaco Pastorius began to develop a unique sound using the electric bass. Apart from jazz fusion and Latin-influenced jazz, the double bass is still widely used in jazz in the 2010s. The deep sound and woody tone of the plucked double bass is distinct from the sound of the fretted bass guitar. The bass guitar produces a different sound than the double bass, because its strings are usually stopped with the aid of metal frets. As well, bass guitars usually have a solid wood body, which means that the sound is produced by electronic amplification of the vibration of the strings. The solid body upright, also known as a "stick" bass or "EUB" variation is still widely used by bass players in salsa and timba bands, because its sound is so well suited to those styles. The EUB is smaller and lighter than a double bass, making touring and travelling easier, and its solid (or mostly solid) body enables bassists to play at a much higher volume with a bass amp without feedback. Playing techniques In jazz, since the 1950s, the double bass is usually played with amplification and it is mostly played with the fingers, pizzicato style, except during some solos, where players may use the bow. The pizzicato style varies between different players and genres. Some players perform with the sides of one, two, or three fingers, especially for walking basslines and slow tempo ballads, because this is purported to create