Question: Are Tommy Karevik and Ben Gibbard both singers?

full_context: Document 1: Ben Gibbard: Benjamin Gibbard (born August 11, 1976) is an American singer, songwriter and guitarist. He is best known as the lead vocalist and guitarist of the indie rock band Death Cab for Cutie, with which he has recorded eight studio albums, and as one half of the electronica duo the Postal Service. Gibbard released his debut solo album, "Former Lives", in 2012, and a collaborative studio album, "One Fast Move or I'm Gone" (2009), with Uncle Tupelo and Son Volt's Jay Farrar.
Document 2: Ben Folds: Benjamin Scott Folds (born September 12, 1966) is an American singer-songwriter and record producer. From 1995 to 2000, Folds was the frontman and pianist of the alternative rock band Ben Folds Five. After the group temporarily disbanded, Folds performed as a solo artist and has toured all over the world. The group reunited in 2011. He has also collaborated with musicians such as William Shatner, Regina Spektor and "Weird Al" Yankovic and undertaken experimental songwriting projects with authors such as Nick Hornby and Neil Gaiman. In addition to contributing music to the soundtracks of the animated films "Over the Hedge," and "Hoodwinked!", Folds produced Amanda Palmer's first solo album and was a judge on the NBC a cappella singing contest "The Sing-Off" from 2009 to 2013.
Document 3: Roy Khan: Roy Sætre Khantatat (born March 12, 1970), is a Norwegian singer-songwriter. Commonly known as Roy Khan or simply Khan, he was the lead vocalist for the symphonic power metal band Kamelot from 1997 to his departure in 2011. He co-wrote most of Kamelot's songs with the band's guitarist and founder Thomas Youngblood during his tenure. Prior to joining Kamelot, Khan was lead singer for the Norwegian progressive metal band Conception from 1991 until 1997 when they disbanded.
Document 4: Andi Kravljaca: Andi Kravljaca is a Bosnian-born Swedish heavy metal singer. His main band is the progressive metal band Aeon Zen, although he is perhaps best known as vocalist for Swedish progressive metal band, Seventh Wonder, appearing on the band's first album, Become, in 2005. He was born in Sarajevo.
Document 5: You Can Play These Songs with Chords: You Can Play These Songs with Chords is an early demo from the rock band Death Cab for Cutie, which at the time consisted entirely of founder Ben Gibbard. This demo was originally released on cassette, and it proved so popular, Gibbard decided to recruit other members to make a full band, which would go on to record "Something About Airplanes", the band's debut studio album.
Document 6: One Fast Move or I'm Gone: One Fast Move or I'm Gone: Kerouac's Big Sur is an album by Ben Gibbard (Death Cab for Cutie) and Jay Farrar (Son Volt), released in 2009. The lyrics are based on the prose of Jack Kerouac's novel "Big Sur" (1962). "One Fast Move or I'm Gone" was a result of Gibbard's and Farrar's mutual appreciation for Kerouac's work while recording several songs for a feature-length documentary of the same name.
Document 7: Kamelot: Kamelot is an American power metal band from Tampa, Florida, formed by Thomas Youngblood and Richard Warner in 1991. The Norwegian vocalist Roy Khan joined for the album "Siége Perilous", and shared songwriting credit with Youngblood until his departure in April 2011. On June 22, 2012, Youngblood announced on their website that their new vocalist is the Swedish singer Tommy Karevik, who was first featured on Kamelot's album "Silverthorn" as main vocalist, co-songwriter and lyricist.
Document 8: Tommy Karevik: Tommy Karevik (born November 1, 1981) is a Swedish metal vocalist, best known as the singer for metal bands Seventh Wonder and Kamelot.
Document 9: Death Cab for Cutie: Death Cab for Cutie is an American alternative rock band, formed in Bellingham, Washington in 1997. The band comprises Ben Gibbard (vocals, guitar, piano), Nick Harmer (bass), Dave Depper (guitar, keyboards, vocals), Zac Rae (keyboards, guitar), and Jason McGerr (drums). In 2014, founding guitarist and producer Chris Walla announced that he would be departing from the band after recording their eighth studio album, "Kintsugi".
Document 10: Tomas Haake: Tomas Haake (born 13 July 1971) is a Swedish drummer and main songwriter of the extreme metal band Meshuggah. He is known for his polyrhythms and technical ability. In 2012, Haake was named the 5th best Modern Metal drummer by MetalSucks.net. In the July 2008 edition of "Modern Drummer" magazine, Haake was named the number one drummer in the "Metal" category, as decided upon in the magazine's Readers' Poll.
Document 11: Silverthorn (album): Silverthorn is the tenth studio album by the American power metal band Kamelot. The album was released on the Steamhammer label, a division of SPV, on October 2012 worldwide. It is the first album to feature Tommy Karevik as the lead singer and their third concept album, after "Epica" (2003) and "The Black Halo" (2005). The concept and story are original, and features a 19th-century little girl named Jolee, who dies in a tragic accident witnessed by her twin brothers. The story deals with how the girl's affluent family handles the tragic event, leading to cover-ups, secrets, and betrayal. The cover by Stefan Heilemann shows Jolee, the main character and angel of afterlife, as an adult.
Document 12: Thomas Gabriel Fischer: Thomas Gabriel Fischer (born 19 July 1963), also known by his stage names of Tom G. Warrior and Satanic Slaughter, is a Swiss metal musician. He is considered to be one of the pioneers of the death metal style of singing, which resembles guttural growling. He led the groups Hellhammer and Celtic Frost, and today is the frontman of the band Triptykon.
Document 13: Know by Heart: Know by Heart is the American Analog Set's fourth studio album. It was released on September 4, 2001, and was their first album on Tiger Style Records. The song "The Postman" contains vocals by guest Ben Gibbard of Death Cab for Cutie and the Postal Service. Gibbard later covered the song "Choir Vandals" on Home Series Vol. V, a split EP with the American Analog Set's own Andrew Kenny. "Gone to Earth" first appeared on AmAnSet's 1996 album "The Fun of Watching Fireworks". "Aaron and Maria" was included in an issue of CMJ New Music Monthly in 2002.
Document 14: The Postal Service: The Postal Service were an American indie rock band from Seattle, Washington, consisted of vocalist Ben Gibbard (of Death Cab for Cutie), producer Jimmy Tamborello (of Dntel and Headset), with Jenny Lewis (of Rilo Kiley) on background vocals.
Document 15: Timo Kotipelto: Timo Antero Kotipelto (born 15 March 1969 in Lappajärvi, Finland) is the vocalist of the Finnish power metal band Stratovarius and is the creator and vocalist of the power metal band Kotipelto. Kotipelto is currently the longest standing member of Stratovarius, after the departure of Timo Tolkki.
ground_truth: yes