A bass player, or bassist, is a musician who plays a bass instrument such as a double bass, bass guitar, keyboard bass or a low brass instrument such as a tuba or sousaphone. Different musical genres tend to be associated with one or more of these instruments. Since the 1960s, the electric bass has been the standard bass instrument for rock and roll, jazz fusion, heavy metal, country, reggae and pop music. The double bass is the standard bass instrument for classical music, bluegrass, rockabilly, and most genres of jazz. Low brass instruments such as the tuba or sousaphone are the standard bass instrument in Dixieland and New Orleans-style jazz bands. Despite the associations of different bass instruments with certain genres, there are exceptions. Some 1990s and 2000s rock and pop bands use a double bass, such as both Andrew Jackson Jihad, Barenaked Ladies; Indie band The Decemberists; and punk rock/psychobilly groups such as The Living End, Nekromantix, The Horrorpops, and Tiger Army. Some fusion jazz groups use a lightweight, stripped-down electric upright bass rather than a double bass. Some composers of modern art music use the electric bass in a chamber music setting. Some jazz big bands use electric bass. Some fusion, R&B and house music groups use synth bass or keyboard bass rather than electric bass. Some Dixieland bands use double bass or electric bass instead of a tuba. In some jazz groups and jam bands, the basslines are played by a Hammond organ player, who uses the bass pedal keyboard or the lower manual for the low notes.