Session musicians (also known as studio musicians or backing musicians) are musicians that are hired to perform in recording sessions and/or live performances. The term sideman is also used in the case of live performances, such as accompanying a recording artist on a tour. Session musicians are usually not permanent or official members of a musical ensemble or band. They work behind the scenes and rarely achieve individual fame in their own right as soloists or bandleaders. However, top session musicians are well known within the music industry, and some have become publicly recognized, such as the Wrecking Crew, the Muscle Shoals Rhythm Section and The Funk Brothers who worked with Motown Records. Many session musicians specialize in playing common rhythm section instruments such as guitar, piano, bass, or drums. Others are specialists, and play brass, woodwinds, and strings. Many session musicians play multiple instruments, which lets them play in a wider range of musical situations, genres and styles. Examples of "doubling" include double bass and electric bass, acoustic guitar and mandolin, piano and accordion, and saxophone and other woodwind instruments. Session musicians are used when musical skills are needed on a short-term basis. Typically session musicians are used by recording studios to provide backing tracks for other musicians for recording sessions and live performances; recording music for advertising, film, television, and theatre. In the 2000s, the terms "session musician" and "studio musician" are synonymous, though in past decades, "studio musician" meant a musician associated with a single record company, recording studio or entertainment agency. Session musicians may play in a wide range of genres or specialize in a specific genre (e.g. country music or jazz). Some session musicians with a Classical music background may focus on film score recordings. Even within a specific genre specialization, there may be even more focused sub-specializations.