A metronome is any device that produces regular, metrical ticks (beats, clicks) — settable in beats per minute. These ticks represent a fixed, regular aural pulse; some metronomes also include synchronized visual motion (e.g. pendulum-swing). The metronome dates from the early 19th century, where it was patented by Johann Maelzel in 1815 as a tool for musicians, under the title "Instrument/Machine for the Improvement of all Musical Performance, called Metronome".

In the 20th century and especially today the metronome is generally positively regarded in Europe and Western culture. The metronome is used by some musicians for practice in maintaining a consistent tempo with steady regular beats and it can be used by composers, as an approximate way of specifying the tempo.

Yet in stark contrast with this positive view, research on the history of the metronome and its influence on performance practice reveals criticisms of metronome use, and highlights differences of "performance practice" and cultural perception/values between the current modern European/Western society (which values the metronome), and the same society during previous times (beginning of the 19th century and earlier: classical/romantic/baroque eras etc.).

György Sándor Ligeti (Hungarian: Ligeti György Sándor, [ˈliɡɛti ˈɟørɟ ˈʃaːndor]; May 28, 1923 – June 12, 2006) was a composer of contemporary classical music. Born into a Hungarian Jewish family in Transylvania, Romania, he lived in Hungary before emigrating and becoming an Austrian citizen.

Ligeti was born in Dicsőszentmárton, which was renamed Târnăveni in 1945, in Transylvania to a Hungarian Jewish family. Ligeti recalls that his first exposure to languages other than Hungarian came one day while listening to a conversation among the Romanian-speaking town police. Before that he hadn't known that other languages existed. He moved to Kolozsvár (Cluj) with his family when he was 6, and he was not to return to the town of his birth until the 1990s.

Ligeti received his initial musical training in the conservatory at Kolozsvár (Cluj), and during the summers privately with Pál Kadosa in Budapest.

In 1940, Northern Transylvania was occupied by Hungary following the Second Vienna Award. In 1944, Ligeti's education was interrupted when he was sent to a forced labor brigade by the Horthy regime. His brother, age 16, was deported to the Mauthausen concentration camp, and both of his parents were sent to Auschwitz. His mother was the only other survivor of his immediate family.

Park Jaebeom (Hangul: 박재범; Hanja: 朴載範, born April 25, 1987), also known as Jay Park, is a Korean-American recording artist, dancer, rapper, music producer, b-boy, songwriter, composer and actor. He was the former leader of the South Korean boy band 2PM, and is a member of the Seattle-based b-boy crew Art of Movement (AOM).

Born in Seattle, Washington, Park showed great interest in hip hop music and breakdancing at a young age. Park was raised in Edmonds, Washington where he attended Edmonds Woodway High School. In 2004, he auditioned in Seattle, Washington, for Korea-based JYP Entertainment (JYPE), which brought him to Korea in January 2005, to receive further training in dancing, rapping, singing, and the Korean language.

Park first appeared through Mnet's Hot Blood Men, a documentary-style reality program that showed the future members of idol groups 2AM and 2PM in training. Park, finishing with the most fan votes, was given the position of 2PM's leader. On September 4, 2008, 2PM debuted with the song "10점 만점에 10점" ("10 Points Out Of 10") on music program M! Countdown after the release of their first mini-album, Hottest Time of the Day, a few days prior.

Jeff Berlin (born January 17, 1953) is an American jazz, jazz fusion and progressive rock electric bass player.

Jeff Berlin's bass playing is somewhat similar to that of Jaco Pastorius, though Berlin plays a fretted bass and has stated his distaste for Jaco imitators.

Jeff Berlin was born to parents who were both musically inclined (his father an opera singer and his mother a pianist). As a child he was considered a prodigy on the violin, but switched to bass guitar at 14 years old. His early bass training included time at the Berklee College of Music in Boston.

Since the 1970s, Jeff Berlin's career has been primarily as a sideman to more well-known musicians, but he has also released several solo albums. He played for some years with Bill Bruford and turned down an offer to join Van Halen.

Berlin is well known as a particularly outspoken advocate of (formal) music education. He was a founding member of the Bass Institute of Technology in Los Angeles and later founded the Players School of Music in Clearwater, Florida. Among his notable pupils are bass guitarists David Hughes and Christopher Maloney. Additionally, he regularly writes articles and columns for Bass Player Magazine.