There have been at least 6 groups, and at least one solo artist, existing under the name 'Carmen'.
1) A unique English-American band, Carmen combined flamenco music with progressive rock. Adding to their distinctiveness was the fact that during long instrumental passages, members of the band would dance onstage, adding those sounds to the instrumental mix.
Carmen consists of:
David Allen (vocals, electric and acoustic guitars, keyboards) who wrote most of the music of Carmen
Roberto Amaral (vocals, vibes, chimes, other percussion) who also wrote several songs and danced with Angela Allen in the flamenco style.
Angela Allen (vocals, piano, mellotron, synthesizer), David Allen's sister, who performed on a special stage together with Roberto during Carmen concerts to amplify the sound of the flamenco dancing.
John Glascock (bass, vocals) joined Jethro Tull after Carmen and played with them for four years (1975-1979). he died at the age of 28.
Paul Fenton (drums)
Carmen's sound was focused on up-beat flamenco guitar with a strong rhythm section and subtle keyboards.
Records:
Fandangos in space - 1974
Dancing on a cold wind - 1975
The Gypsies - 1976
2) A melodic rock band, formed in Cheltenham, England in 2004. Their songs range in dynamic from heavy to gentle, incorporating distorted guitars, strings, synthesisers and layered vocal lines. Their debut album, 'Angels And Dust' is released 30th June 2008 on the Casket label. Official site.
3) 4 piece hardcore band from Rochester, Kent "From down south (Kent way), Carmen have been a band that never got anywhere to be honest, not for want of trying. As far as I know this is all they ever recorded, 2 tracks of noisy, chaotic, screaming fury. Sorta like Breach mixed with Deadguy, sorta. Best making up your own mind." (source http://exwhorism.blogspot.com/)
http://www.myspace.com/carmen
4) A 1980's teenage funk/soul singer.
5) A German post-punk outfit from early 80's.
6) The similarly-named Christian solo act Carman.
7) A heavy metal band from Hungary