An orchestra is a large instrumental ensemble that contains sections of string, brass, woodwind, and percussion instruments. The term orchestra derives from the Greek ορχήστρα, the name for the area in front of an ancient Greek stage reserved for the Greek chorus. The orchestra grew by accretion throughout the 18th and 19th centuries, but changed very little in composition during the course of the 20th century.

A smaller-sized orchestra for this time period (of about fifty players or fewer) is called a chamber orchestra. A full-size orchestra (about 100 players) may sometimes be called a "symphony orchestra" or "philharmonic orchestra"; these modifiers do not necessarily indicate any strict difference in either the instrumental constitution or role of the orchestra, but can be useful to distinguish different ensembles based in the same city (for instance, the London Symphony Orchestra and the London Philharmonic Orchestra). A symphony orchestra will usually have over eighty musicians on its roster, in some cases over a hundred, but the actual number of musicians employed in a particular performance may vary according to the work being played and the size of the venue. A leading chamber orchestra might employ as many as fifty musicians; some are much smaller than that. Orchestras can also be found in schools. The term concert orchestra may sometimes be used (e.g., BBC Concert Orchestra; RTÉ Concert Orchestra)—no distinction is made on size of orchestra by use of this term, although their use is generally distinguished as for live concert. As such they are commonly chamber orchestras.

Katheryn Elizabeth Hudson (born October 25, 1984), known by her stage name Katy Perry, is an American singer, songwriter and actress. Perry grew up with gospel music, and during her first year of high school she pursued a music career as Katy Hudson, releasing her first studio album called Katy Hudson which failed to chart. She recorded a solo album later, which was never released. After signing with Capitol Music Group in 2007, her fourth record label in seven years, she adopted the stage name Katy Perry.

She first gained recognition with the release of her first mainstream album, One of the Boys in 2008, which spawned three Billboard Hot 100 top-ten songs—"I Kissed A Girl", "Hot n Cold" and "Waking Up In Vegas". Perry supported the album with her Hello Katy Tour. In 2010, her third studio album, Teenage Dream (2010), which topped the Billboard 200 chart, and spawned five number one singles—"California Gurls", "Teenage Dream", "Firework", "E.T." and "Last Friday Night (T.G.I.F.)"—Teenage Dream was the only album (after Michael Jackson's Bad)—to do so, and the first female in history to achieve this milestone. She embarked on the California Dreams Tour, which grossed nearly $60 million worldwide. Perry re-released the album under the name of Teenage Dream: The Complete Confection on March 26, 2012, and the re-release has already spawned the number-one single "Part of Me".

Lindsey Stirling (born on September 21, 1986) is an American violinist, musician, dancer, performance artist, and composer. In 2010 she competed on the fifth season of America's Got Talent. Stirling is noted for her versatility performing music from country to hip hop.

At the age of 23 Stirling was a quarter-finalist on the fifth season of America's Got Talent where she was known as the ‘Hip Hop Violinist’. After Stirling's performance, Sharon Osbourne said, "Wow... we love you Lindsey!” and Piers Morgan called her performance "Electrifying!".

At the age of 5, after being influenced by the classic music records played by her father, Stirling requested the opportunity to learn and play the violin.

Stirling was classically trained through private lessons for 12 years. When she was 16, she joined a rock band with four friends called Stomp on Melvin. As part of her experience with Stomp on Melvin, Stirling wrote a solo violin rock song, and her performance helped her to win both the title of Arizona’s Jr. Miss in 2005 and the talent category of the National Jr. Miss Pageant. As of May 2, 2012, Stirling is 5'3" tall.

Johann Sebastian Bach (31 March [O.S. 21 March] 1685 – 28 July 1750) was a German composer, organist, harpsichordist, violist, and violinist of the Baroque Period. He enriched many established German styles through his skill in counterpoint, harmonic and motivic organisation, and the adaptation of rhythms, forms, and textures from abroad, particularly from Italy and France. Bach wrote much music, which was revered for its intellectual depth, technical command, and artistic beauty. Many of his works are still known today, such as the Brandenburg Concertos, the Mass in B minor, the Well-Tempered Clavier, and his cantatas, chorales, partitas, passions, and organ works.

Bach was born in Eisenach, Saxe-Eisenach into a very musical family; his father, Johann Ambrosius Bach was the director of the town's musicians, and all of his uncles were professional musicians. His father taught him to play violin and harpsichord, and his brother, Johann Christoph Bach taught him the clavichord, and exposed him to much contemporary music. Bach also sang, and he went to the St Michael's School in Lüneburg, because of his skill in voice. After graduating, he held several musical posts across Germany; he served as Kapellmeister (director of music) to Leopold, Prince of Anhalt-Köthen, Cantor of Thomasschule in Leipzig, and Royal Court Composer to August III. Bach's health and vision declined in 1749, and he died on 28 July 1750. Modern historians believe that his death was caused by a combination of stroke and pneumonia.

Sebastian Bach (born April 3, 1968) is a Canadian heavy metal singer who achieved mainstream success as frontman of Skid Row from 1987 to 1996. Since his departure from Skid Row, he has had many television roles, acted in Broadway plays, and led a successful solo career.

Bach was born Sebastian Philip Bierk on April 3, 1968, in Freeport, Bahamas, and raised in Peterborough, Ontario, Canada. He attended nearby Lakefield College School in the same class as Michael Kulas, of the British rock group James, a year behind Felipe, Prince of Asturias and a year ahead of the comedian/actor Will Arnett. He is of Norwegian, French Canadian, and Native American descent. Bach's father was the visual artist David Bierk. He is the brother of retired NHL goaltender Zac Bierk, model/actress Heather Dylan Bierk, and Toronto-based artists Jeff, Nick, Alex, and Charles Bierk.

Skid Row initially formed in the late eighties with lead singer Matt Fallon. They began playing at various New Jersey clubs. Fallon would soon leave the band in 1987, leaving Skid Row without a singer. Bach, who had just left his previous band Madam X, was spotted singing at rock photographer Mark Weiss's wedding and the members asked him to join. He turned them down, but changed his mind after hearing the demo tapes of "Youth Gone Wild" and "18 and Life". He sent them a demo of him singing "Saved By Love." They loved it and flew him to New Jersey where they began playing gigs. Sebastian also recorded demos with Bon Jovi & Sabo's friend Jack Ponti. (The song "She's on Top" later came out on Jack Ponti Presents Vol. 1)