Wikipedia (www.wikipedia.com) defines Karaoke as "(Japanese: カラオケ, from 空 kara, "empty", and オーケストラ ōkesutora, "orchestra") is a form of entertainment where recorded music accompanies an amateur singer who sings along with the accompaniment on microphone. The music is of a well-known song in which the voice of the original singer is absent or reduced in volume. Lyrics are usually also displayed, sometimes including color changes synchronized with the music, on music video to help with the sing-along.
Karaoke has been a popular form of entertainment in East Asia since at least the 1980s, and has since spread to other parts of the world. Karaoke engenders quite a bit of culture specific to its enthusiasts, and this culture, unsurprisingly, varies from country to country."
"A basic karaoke machine consists of audio input, a means of altering the pitch of the music (not the singer) and an audio output. Some low-end machines attempt to provide vocal suppression so that one can feed regular songs into the machine and suppress the voice of the original singer, however this is not very effective (see below). Most common machines are audio mixers with microphone input built-in with CD+G, Video CD, Laser Disc, or DVD players. CD+G players use a special track called subcode to encode the lyrics and pictures displayed on the screen, while the other formats natively display both audio and video. In some countries, karaoke with video lyrics display capabilities is called KTV.
Most karaoke machines have technology that electronically changes the pitch of music so that amateur singers can sing along to any music source by choosing a key that is appropriate for their vocal range, while maintaining the original tempo of the song. (There were some very old systems that used cassettes, and these changed the pitch by altering playback speed, but none are still on the market, and their commercial use is virtually nonexistent.)
A popular game using karaoke is to randomly type in a number and call up a song, which participants take a turn to try to sing as much as they can. In some machines, this game is pre-programmed and may be limited to a genre so that they cannot call up an obscure national anthem that none of them can sing. This game has come to be called "Kamikaze Karaoke" in some parts of the United States and Canada.
Many low-end entertainment systems (boom boxes etc) have a karaoke mode that attempts to remove the vocal track from general (non-karaoke) audio CDs. This is done by center removal which exploits the fact that in most music the vocals are in the center. This means that the voice, as part of the music, has equal volume on both stereo channels and no phase difference. To get the quasi-karaoke (mono) track the left channel of the original audio is subtracted from the right channel. The crudeness of that approach is reflected in the often poor performance of voice removal. Common effects are hearing the echo of the voice track (due to stereo echo being put on the vocals), and also other instruments that happen to be mixed into the center get removed (snare/bass drum, solo instruments), degrading this approach to hardly more than a gimmick in those devices."
